So I just hit the 1000 mile mark on my RX-8. It's a 2004. I'm thinking it might have the J flash, since it has a sticker under the hood that says "Port Campaign" and has a date in February of 2004. No letters before the "Port Campaign" however.

The last 2 tanks, I got 13.872 MPG, and then 14.256. I'm not easy on the throttle, but I'm not hard all the time. I would expect something closer to 18 MPG...

Can anyone tell me if the "Port Campaign" thing mentioned in the Flash thread is supposed to have the letters in front of it?

I'll go down to the dealer when then open again after christmas and find out what flash I have - In the mean time, it's just speculation.

Do some reading and searching on this forum.

You're going to need more info on the Port Campaign. It should have a rework number. Do a search on that number.

Some owners complain of low mpg (mostly those with early build dates). Mine has build date of 6/03 and I get the advertised 18mpg.

Also what kind of driving do you do? City/Highway, etc? I've went to 50/50 driving to 90 city driving from 18mpg down to 16mpg.

I suspect it's probably not the updated M flash that solves mpg and also flooding issues.

Mine had the M flash (Authorized Modification: MSP04) before I picked it up. I think all the flashes use the same mod#, it's the date that tells the flash level. My 18mpg is mostly city and 22mpg mostly highway.

Here is a pic of the Port Campaign sticker (it's the Rework# that's important).

http://www.rx8club.com/attachment.php?attachmentid=3041

Is this rework number on all cars? Where would I find this on my car?

When you fill up your tank are you putting in about 13.5 gallons? And are you getting around 220mi per tank? You're getting around 16+mi/gal.

My 8 has almost the identical build date as yours (June 04). Most of my driving is highway with a little city thrown in. I average about 22 mpg and get 24 on long highway drives. The best has been 25.4 on a tank driving about 65 mph. The worst was 19 when my two sons drove it around Detroit. Cold weather drops it to about 20. By the way, I have kept track of every gallon of gas that I have bought and calculate the mileage on each tank. From what I have read, I feel fortunate to do as well.

I have thread for improving mileage in the gulf coast thread, these are my impressions for down here in Houston but they may help you. Mine has gotten better with time now that I've got about 7,200 miles.

Is this rework number on all cars? Where would I find this on my car?

Should be on the under-side of the hood near the latch.

with m flash i still get 15 mpg, not complaining I do mostly stop light to stop light driving, and shifting above 4k rpms.

well to answer your question. it seems that is about what people are getting more or less. so is it normal? well it is consistant with other people. is it good? not really. I am getting lo 20s pretty regulary city and freeway driving, not sure why, but I only check eery other month or so, I dont check it regulary or really care too. either way I have to buy gas, and if my other choise is driving a different car, then I will just drive the RX8 and enjoy the driving and not worry about the mpg! jmo.

Please lets not make this another "I'm getting bad gas milage too" type of thread. I'm just started this thread to let everyone know that I am taking my car to the dealer tomorrow to look at possible reasons why I'm getting 10mpg or less on my fuel economy. Yes I'm at the latest flash. Yes I do drive a bit hard, but I still typically shift at 6k or so.

I do have my mileage log ready to show the service people at Mazda. I also searched and found a few things that could have caused this problem. Some of them include the thermostat being stuck open. And also the vehicle possibly being flooded before I took delivery possibly causing the catalyst to break up if fuel got in there. I took delivery of the car with the K flash and 36 miles on it, so that's a possibility.

Is there anything else that I could possibly bring up to the dealer? Any input you guys/gals have would be extremely helpful. I bought the RX-8 knowing I'd get poor MPG, but 10mpg is a headache ;) Thanks in advance everyone.

I sorry to say it may take a few miles being driven to prove your point..

Are you prepared to give the dealership permission to take the car on an extended drive?

Most likely the thermostat would flag a CEL. IE P0128 (04's only)

If I were the service guy I would stick someone in the car and send them down the interstate for at least a 90-100 mile round trip to give them some real numbers to call the tech line with.

Let us know how it goes.

Just something to think about...they "may" try to blame some of your problem on "wider tires". The increased rolling resistance will not get you down to 10 mpg. Just food for thought. BTW, I got 18mpg out of the last tank with mostly city driving. Just thought I would put in my .02 as a defense posture.
BTW they are mounting the new tires as a write this.
Good luck..from another Ti.
Paul

Do some reading and searching on this forum.

You're going to need more info on the Port Campaign. It should have a rework number. Do a search on that number.
I did a search for my rework Number. No matches. The rework # is: 04B01
Port Code: 49159
Date: 2/12/04

Thanks,

Terry

I sorry to say it may take a few miles being driven to prove your point..

Are you prepared to give the dealership permission to take the car on an extended drive?

Most likely the thermostat would flag a CEL. IE P0128 (04's only)

If I were the service guy I would stick someone in the car and send them down the interstate for at least a 90-100 mile round trip to give them some real numbers to call the tech line with.

Let us know how it goes.

Yeah, I figured that much. I don't mind them taking it for a drive. Though driving on the interstate is not a very accurate test. I live in NJ and you'll do 75% city driving out here.

I fogot to mention that during the first 5-10 minutes of driving I can smell fuel when I start off from a dead stop. So I think the car is running SUPER RICh. Who knows, maybe they will change out the MAF sensor and wiring. I've heard there is a large degree of seperation between everyone's MAF voltage which is mainly due to poor wires.

In my opinion, you are approaching this issue correctly. With your log, which I assume contains mileage, gallons of gas, and so on, is definitely the best you can do to show them that there is a problem. The first thing ya gotta do is convince them that you actually have a problem and your log should do just that. They're not going to be motivated to help if they don't believe you.

I think the mistake that some with this problem make is to not provide some sort of documentation to back up their claim. Sure, as far as the service person knows, it's only some numbers that you wrote down in your log. BUT, that attitude doesn't really matter because if this problem eventually rises to a legal confrontation, you will be in the drivers seat :) with the documentation and the service guy should realize that.

I would take the original log in with you and also make a copy of it for them to attach to the work order. Good luck and let us know what happens.

In my opinion, you are approaching this issue correctly. With your log, which I assume contains mileage, gallons of gas, and so on, is definitely the best you can do to show them that there is a problem. The first thing ya gotta do is convince them that you actually have a problem and your log should do just that. They're not going to be motivated to help if they don't believe you.

I think the mistake that some with this problem make is to not provide some sort of documentation to back up their claim. Sure, as far as the service person knows, it's only some numbers that you wrote down in your log. BUT, that attitude doesn't really matter because if this problem eventually rises to a legal confrontation, you will be in the drivers seat :) with the documentation and the service guy should realize that.

I would take the original log in with you and also make a copy of it for them to attach to the work order. Good luck and let us know what happens.


Thanks a lot for the comments. I started my log the minute I drove off the dealers lot ;) So I am hoping that it carries some sort of weight.

You claim you drive it hard. Of course, that's difficult to quantify. As a point of reference, I would suggest making a "mileage run" with an attempt to optimize. I'd do a freeway drive at a steady 65mph, and run through at least 1/2 tank of gas, preferably closer to a full tank, and see what kind of mileage you get.

Of course, you may have a problem that affects city driving and doesn't show up during highway cruise, but I think the test is worth it. If you get bad mileage with this test, then you've eliminated "driving style" from even being an issue.

I did a search for my rework Number. No matches. The rework # is: 04B01
Port Code: 49159
Date: 2/12/04

Thanks,

Terry

Mine has that port campaign sticker. I'm pretty sure it was for the airbag wiring harness recall.

EDIT: yeah, that's it. This was a recall from Feb2004. Cars in port or arriving at port during that time had the repair done at the port. Mine was done on 2/20/04, work # 04b01, port code 49159.

http://www.finishlineperformance.com/rx8/docs/airbag_recall.htm

The L and M flashes didn't come out until after I'd taken delivery. I finally got the M flash in June.

You claim you drive it hard. Of course, that's difficult to quantify. As a point of reference, I would suggest making a "mileage run" with an attempt to optimize. I'd do a freeway drive at a steady 65mph, and run through at least 1/2 tank of gas, preferably closer to a full tank, and see what kind of mileage you get.

Of course, you may have a problem that affects city driving and doesn't show up during highway cruise, but I think the test is worth it. If you get bad mileage with this test, then you've eliminated "driving style" from even being an issue.


The last road trip I made was 180 miles round trip. I averaged 15.1 mpg for that trip. My average speed was 70mph in 6th gear.

The first road trip I made was 225 miles round trip. I averaged 18.9mpg. My average speed was 85mph in 6th gear

I went in for a CEL and poor mileage (now down to 9-10 and getting worse) and mentioned in passing that I heard a squeal from the brakes the other day and when I got my car back, they had changed the gas cap for the CEL and replaced the front pads, with just me mentioning it in passing.

Of course they were still having problems with the WDS and the new flash not downloading to any cars and thus did not even attempt to address my mileage concerns stating that I would have to bring it back in when they could get the flash to download to a car. The guy even said that my mileage was probably normal.

So I still get about 120 miles to a tank of gas no matter how I drive.......................

but my breaks don't squeal. Nope they don't squeal at all. It's a wonder I heard them squeal that one time with all the yelling and screaming I do after filling up.:(

The guy that said that milage was normal was full of crap (unless you drive it 10/10s all the time). Normal, for a normal driver, should be 18+ MPG really. 260+ miles to a tankfull.

If they can't get that milage up there closer to those numbers then you need to talk to Mazda USA and mention the word 'lemon' during the conversation.

The guy that said that milage was normal was full of crap (unless you drive it 10/10s all the time). Normal, for a normal driver, should be 18+ MPG really. 260+ miles to a tankfull.

If they can't get that milage up there closer to those numbers then you need to talk to Mazda USA and mention the word 'lemon' during the conversation. Yeah I know, but they have been very carefull to not put the actual words "poor mileage" on any tickets that get sent to Mazda NA. Instead they say "poor performance" or "flooding" or completely leave it off and just say that it is normal.

The actual performance has picked up just a bit since they changed the gas cap, but the mileage is no different. Of course the tires aren't as sticky in this cold weather either.

As I mentioned in my now infamous "spoke to a mazda engineer" post, I followed the recommendation of using a certain type of gas. He recommended using any gas that uses less than 10% or no ethanol or any of the "nols". Specifically, Sunoco Ultra 94. However, as many of you know, or have read that most gas in the MW and NE is 10% ethanol throughout the winter months, and it may be that way all over....I dont know.

Typically premium gas is 92 in Michigan, Sunoco was the only station to offer 94, unless it racing fuel....So that is what I have been running on since. I am on my 2nd tank and I have noticed a marked improvement.

With the 1st tank, I drove 120 miles of mixed driving, however, curious whether or not the extra octane would yield more power, I beat on it pretty hard.... I filled up again at the same gas station as my guage was reading 3 ticks below 1/2 a tank. When I filled up, it only too 8 gallons. The guage as we all know was way off. I know that this is only 15mpg, but I was very hard on the car. Typically if I was driving this hard, I would expect 10mpg. Now since this did not really offer me any base for comparison, after I filled up...I vowed not to drive the car so hard. In mixed driving, I have currently 155 miles on my trip meter and the "always accurate" guage is at 1/2. Let's just say the guage is right.....I am on track for getting 280 miles out of this tank.....which is huge considering that I have never gotten more than 220 at the onset of the fuel light. I plan on buying gas again today to confirm the mileage and will post again.

Sorry for the long post.....Happy New Year.

The only port campaign I know about was the original PCM reflash to meet EPA2 standards.

All 8's at port were stopped for this reason. So any that were sitting at the port without this flash should have this port campaign sticker. Any cars shipped after that would have been reflashed at the factory.

As I mentioned in my now infamous "spoke to a mazda engineer" post, I followed the recommendation of using a certain type of gas. He recommended using any gas that uses less than 10% or no ethanol or any of the "nols". Specifically, Sunoco Ultra 94. However, as many of you know, or have read that most gas in the MW and NE is 10% ethanol throughout the winter months, and it may be that way all over....I dont know.

Thanks for the comments, though I don't suspect that it's the type of gas I'm using since I go to Sunoco for gas too ;)

On another note, I dropped it off this morning to the dealer. They were rather surprised I had a mileage log and knew what I was talking about. I let them know to check the thermostat and catalyst to see if those are the culprits. They said they have to call Mazda North America and talk to their engineers to troubleshoot the problem. They also said they may have to do a MPG test. Hope they don't destroy my 8 in the process :eek:


I also let them know that I smell unspent fuel during the first 5-10 minutes of driving when I'm in 1st and 2nd gear. This is intermittant and only happens at WOT. I think something is making the car run very very rich. But we'll see what happens.

In the mean time, the dealer gave me a loaner car, a Mazda 6 with a V6 engine in it. Not too shabby. This car only has 75 miles on it ;) Time to beat the hell out of it. Should be fun in the snow :)

I'll keep everyone interested up to date on the latest and greatest that I find about this issue. Thanks to everyone for the comments!

I sorry to say it may take a few miles being driven to prove your point..

Are you prepared to give the dealership permission to take the car on an extended drive?

Most likely the thermostat would flag a CEL. IE P0128 (04's only)

If I were the service guy I would stick someone in the car and send them down the interstate for at least a 90-100 mile round trip to give them some real numbers to call the tech line with.

Let us know how it goes.

Mine was stuck open but no CEL

OH HOWARD GOT TO IT FIRST:) it can be stuck without a cel just like a cat can be partially clogged and not throw a cel. philodox it seems you are going about things the right way. make sure you report back what they find. thanks and i hope they find a resolution:)

on a side note- my mpg has recently fallen from its normal 16 around town to about 14. ive been on it a little more recently so that could be it. ill keep an eye on it.

there was also the port campaign to change some dipsticks. plus one for each recall to fix the cars in port. plus one to change something in the manual etc. anytime a flash or recall or very important tsb there is a port campaign to fix those cars.

I went to the dealer back about 6 months ago complaining of poor MPG. They took my car on a trip to Sacramento and back on CC at 70mph and averaged 22mpg. The best MPG I have gotten so far was 21, but I wasn't on CC.

Well, Just picked my car up from the dealer. They talked to Mazda USA tech service on the phone. They have no clue what may be causing it. Mazda USA has no way to check MPG without driving the car. Apparently most vehicles can check MPG through the CAN bus by measuring fuel spent vs. RPM/Gear or something like that. Apparently the RX-8 isn't capable of this test.

I had the dealer check for fuel leaks and they found none. They swear to me upon the bible that my Borla Cat-Back exhaust is the culprit and that if I put the stock exhaust back on that I'll get an extra 8mpg. What bullshit. I'm calling Mazda USA to complain to them first hand.

Will keep everyone posted on how things go.

you should have left it with them to test the mpg. but of course you would want a loaner and they would say no loaner because we think its your exhaust yadd yadda...

do you have any receipts showing when you got the borla. can you ompare the date with your mpg log to see if there was a change BB(before borla) to AB ?

I went to the dealer back about 6 months ago complaining of poor MPG. They took my car on a trip to Sacramento and back on CC at 70mph and averaged 22mpg. The best MPG I have gotten so far was 21, but I wasn't on CC.

Excuse me for not being familiar with CA. How far is Sacramento from CC? They just took it for a road trip to check gas mileage?

you should have left it with them to test the mpg. but of course you would want a loaner and they would say no loaner because we think its your exhaust yadd yadda...

do you have any receipts showing when you got the borla. can you ompare the date with your mpg log to see if there was a change BB(before borla) to AB ?

Oh yeah, I put the Borla on with 200 miles on the car. I was still getting 15mpg or so until about 2 months ago when the MPG has steadily gone through the toilet.

cc=cruise control and yes in order for the techs to do something about your complaint they have to verify the problem exists i.e. drive the car.

OH HOWARD GOT TO IT FIRST:) it can be stuck without a cel just like a cat can be partially clogged and not throw a cel. philodox it seems you are going about things the right way. make sure you report back what they find. thanks and i hope they find a resolution:)

on a side note- my mpg has recently fallen from its normal 16 around town to about 14. ive been on it a little more recently so that could be it. ill keep an eye on it.

Is Howards car an 04? As some of you remember we saw many thermostats replaced last winter for a P0128 code..

Any one with access to the codes may notice the 128 has been dropped for the 05's

my mileage in city has dropped from 14 to 11-12 since it got very cold all im doing differently is letting it warrm up for 3-5 minutes before i go, is it possible that im losing the mileage in warmup??? coz this is unacceptably low.

my mileage in city has dropped from 14 to 11-12 since it got very cold all im doing differently is letting it warrm up for 3-5 minutes before i go, is it possible that im losing the mileage in warmup??? coz this is unacceptably low.

Thanks for the comments, but lets not get off topic here ;) But yeah, may be the cold.. or something else.. once I find out what's going on with mine, I'll let everyone know.

Excuse me for not being familiar with CA. How far is Sacramento from CC? They just took it for a road trip to check gas mileage?

sorry, they drove up to Sacramento from their shop in Burlingame on Cruise Control (CC). Yes, they did indeed take it for a 1 day roadtrip and checked the mileage.

Is Howards car an 04? As some of you remember we saw many thermostats replaced last winter for a P0128 code..

Any one with access to the codes may notice the 128 has been dropped for the 05's
August 03

The tires that came with the car are downright dangerous in cold, slick weather. Many threads and posts on this one. The biggest problem is getting the better tires as they are still in short supply because they are they same size as those used on the 350Z thus are in high demand.

The mileage is BS...and they know it. You need to press that one with Mazda USA directly.

Mazda doesn't set the MPG. The EPA does. Mazda cannot modify the sticker.

If you keep the RPMs low you will get EPA numbers. Of coarse your car will feel like it has 100 HP, but that is how the EPA drives.

Problem is most 100HP cars still have much better MPG than the RX-8 even if you keep its RPMs low. Now, take the RPMs up on the RX-8 and you have a 200+ HP car that gets millage more like a 300+ HP car.

Mazda is the beneficiary of the deception (i.e. a price sticker that says "239 HP" motor with decent EPA numbers), but they aren't the cause of it.

-Mr. Wigggles

Mazda doesn't set the MPG. The EPA does. Mazda cannot modify the sticker.

If you keep the RPMs low you will get EPA numbers. Of coarse your car will feel like it has 100 HP, but that is how the EPA drives.

Problem is most 100HP cars still have much better MPG than the RX-8 even if you keep its RPMs low. Now, take the RPMs up on the RX-8 and you have a 200+ HP car that gets millage more like a 300+ HP car.

Mazda is the beneficiary of the deception (i.e. a price sticker that says "239 HP" motor with decent EPA numbers), but they aren't the cause of it.

-Mr. Wigggles
What you are saying may be true for your car, the way my car should be and most others, but it does not apply to the way mine is. I have tried keeping the rpms below 3500 (worst mileage of all at 8.7), below 4500(9.7mpg), between 3000 and 6000(9.5) and WOT to redline in every gear(10.1mpg) and it doesn't differ. I have let friends drive it and they get the same results so it is not me.

I don't give a crap what the sticker says, I know people with Vipers and Ford GTs(500+ HP cars) that get better mileage. I get 19.8 in town in my F150 Supercrew PU. My RX4 got over 20mpg and I was young and drove it hard all the time.

Nothing you said has anything to do with the problem my RX8 has with it's gas consumption.

What you are saying may be true for your car, the way my car should be and most others, but it does not apply to the way mine is. I have tried keeping the rpms below 3500 (worst mileage of all at 8.7), below 4500(9.7mpg), between 3000 and 6000(9.5) and WOT to redline in every gear(10.1mpg) and it doesn't differ. I have let friends drive it and they get the same results so it is not me.

I don't give a crap what the sticker says, I know people with Vipers and Ford GTs(500+ HP cars) that get better mileage. I get 19.8 in town in my F150 Supercrew PU. My RX4 got over 20mpg and I was young and drove it hard all the time.

Nothing you said has anything to do with the problem my RX8 has with it's gas consumption.

So the best you are getting is 10.1 mpg? There is something wrong with your car. Get on the phone with MNA asap, and so not take no for an answer!

btw, I am getting about 18 mpg, sometimes a litttle less, sometimes a little more, driving fairly normal.

What you are saying may be true for your car, the way my car should be and most others, but it does not apply to the way mine is. I have tried keeping the rpms below 3500 (worst mileage of all at 8.7), below 4500(9.7mpg), between 3000 and 6000(9.5) and WOT to redline in every gear(10.1mpg) and it doesn't differ. I have let friends drive it and they get the same results so it is not me.

I don't give a crap what the sticker says, I know people with Vipers and Ford GTs(500+ HP cars) that get better mileage. I get 19.8 in town in my F150 Supercrew PU. My RX4 got over 20mpg and I was young and drove it hard all the time.

Nothing you said has anything to do with the problem my RX8 has with it's gas consumption.

Forgive me if I missed this somewhere in prior posts, but how many miles do you have on your 8?

So the best you are getting is 10.1 mpg? There is something wrong with your car. Get on the phone with MNA asap, and so not take no for an answer!

btw, I am getting about 18 mpg, sometimes a litttle less, sometimes a little more, driving fairly normal.
I have emailed them with the specifics.

Forgive me if I missed this somewhere in prior posts, but how many miles do you have on your 8?
Last time I looked it was about 9600 miles. It had 7500 on it back in May when this mess started happening.

I have emailed them with the specifics.I got a response telling me to have the service manager make an appointment with the District Customer Support Manager (DCSM) the next time he visits the dealership (4-6 weeks).

If anyone has a direct line for this let me know.

Last time I looked it was about 9600 miles. It had 7500 on it back in May when this mess started happening.

Who typically does the service on your 8? Please don't say Joe Meyers.

Who typically does the services on your 8? Please don't say Joe Meyers.Nope, Joe Myers.

Nope, Joe Myers.

Didn't I ask you not to say those two words. Heh. I had alot of issues with that dealership back when I had my 2nd gen rx-7. For some reason they had a terrible time diagnosing problems and finding solutions. Have you tried another dealership?

Didn't I ask you not to say those two words. Heh. I had alot of issues with that dealership back when I had my 2nd gen rx-7. For some reason they had a terrible time diagnosing problems and finding solutions. Have you tried another dealership?
All things being equal and all dealerships being responsible to Mazda, there should be no reason for me to have to drive even farther and waste even more gas to take it to another dealership. That is the dealership where I purchased the car and while I have no specific loyality to that one dealership I do not feel it is my responsibility to take the car elsewhere when Mazda has certified them as being prepared and able to make warranty fixes. If that is not the case, then Mazda needs to know so they can take whatever action is necessary to pull the franchise agreement.

All things being equal and all dealerships being responsible to Mazda, there should be no reason for me to have to drive even farther and waste even more gas to take it to another dealership. That is the dealership where I purchased the car and while I have no specific loyality to that one dealership I do not feel it is my responsibility to take the car elsewhere when Mazda has certified them as being prepared and able to make warranty fixes. If that is not the case, then Mazda needs to know so they can take whatever action is necessary to pull the franchise agreement.

I completely agree. As sad as it is it just seems that all dealerships are not equal when it comes to service. I am just familiar with Joe Myers since my parents live in Tomball and that dealership always serviced my rx-7. I never did seem to have very good luck with them. I live in Austin now, but purchased my latest rx-8 from Munday Mazda. No clue as to how their service department rates, sales experience was good though. :) Sorry to hear that you have had problems with your rx-8. I just hit the 600 miles mark on my 2005 today so we will see how things go on this end.

split this conversation out from the other thread. carry on:)

Holy sheep shit. I did a master reset of the ECU. Not the 20 brake stomp one, but holding the trip meter button down while turning the ignition to the on position. I did that three times. Now for the amazing part. My last tank of gas was 22mpg. How the hell do I go from 10mpg to 22mpg? Could my ECU have been that confused that it was running "warm up" rich all the time? Very Very strange.......

Holy sheep shit. I did a master reset of the ECU. Not the 20 brake stomp one, but holding the trip meter button down while turning the ignition to the on position. I did that three times. Now for the amazing part. My last tank of gas was 22mpg. How the hell do I go from 10mpg to 22mpg? Could my ECU have been that confused that it was running "warm up" rich all the time? Very Very strange.......

WOW! That IS amazing. Is it possible that you may have hit on a "fix" for the low mileage problem? If I had the problem, I would immediately zero-out the PCM. Nothing to lose and everything to gain I would think.

Keep us up-to-date on your mileage in the next couple of months.

Holy sheep shit. I did a master reset of the ECU. Not the 20 brake stomp one, but holding the trip meter button down while turning the ignition to the on position. I did that three times. Now for the amazing part. My last tank of gas was 22mpg. How the hell do I go from 10mpg to 22mpg? Could my ECU have been that confused that it was running "warm up" rich all the time? Very Very strange.......

Philodox,

FWIW I had the battery out of my car while installing a ground wire set ( I know, don't start the flames, it may not help but it shouldn't hurt). I autox'ed the next day and only had about 6 gallons of gas in the car. Filled up after the autox and the next tank mpg dropped to 13 from my normal 17+ city 20+ highway. I was about to get worried and I noticed it "gradually" crept back up. I guess it was about 3-4 tanks full before it was back to "normal". Filled up yesterday, mpg was 18 in town.

With your experience I wonder if the ECU "hiccuped" and hung in the rich mode causing the poor mpg. My experience was it took about 750-1k miles to reset itself. Could the KAM have anything to do with this?

om-nc

WOW! That IS amazing. Is it possible that you may have hit on a "fix" for the low mileage problem? If I had the problem, I would immediately zero-out the PCM. Nothing to lose and everything to gain I would think.

Keep us up-to-date on your mileage in the next couple of months.


When they reflashed mine does that reset it? I assume it does. That didn't change my mileage.

Could the KAM have anything to do with this? om-nc

It certainly would be nice to know a bit more about the KAM. In fact, I think I will start a new thread on this topic.

It certainly would be nice to know a bit more about the KAM. In fact, I think I will start a new thread on this topic.

I had to search for it, so here it is: http://www.rx8club.com/showthread.php?t=48768

1st Tank 18.33 mpg, cruze control set the entire way @ 85mph.
2nd Tank 20.90 mpg, cruze control set @ 85mph
3rd Tank 17.33 mpg, cruze control set @ 102mph, and upwards of 120mph at various points. (Lousiana to Texas "bridge", everyone was doing 100+)
4th Tank ??? don't know yet.

I think I missed a tank full in there...

Anyway, basically, for my RX-8, on the Highway I get ~18.5-19mpg doing around 80ish... City I'm getting 15.5ish.

Still not very impressive, and no, I'm not going to go 55mph... Speed limits here are 70mph, do 80-85mph is "common".

I still don't see how people are getting 24+ mpg.

I really think they need to change the epa mpg rating to 14/19 for this car.

you have a problem. i can routinely get 23+ mpg on long highway stretches with cruise set 80-85. are you sure you were in 6th? the only time on the highway i got less then 22ish was when i was 95-100+ for a long ways.

Mine gets 21-23 mpg at varying speeds from 70-95 mph on the highway (no congestion).
About 13-14 mpg in the "round town" driving I usually do (many trips to the beep).

see my post in the gulf regional section about ways to improve your gas mileage

How long is a 'long stretch'?

And geesh...you fockers SPEED a LOT! :)

:D

Becareful on that I10 bridge 'Atchafalaya' causeway--they use aerial enforcement sometimes. A friend of mine got popped on it. With my Cobra radar, which isn't the best, I speed all the way down I10 EXCEPT for on those stretches of causeway.

i mean all highway tanks. fill up get back on the highway and then get back off for another fill up. from portland to irvine california i never got below 23 mpg until the one stretch in cali when a whole bunch of 8s and 7s were together doing over 90 and at times as high as 120. that tank i got 19-20 mpg( there might have been one tank that was like 18.8 or something in there). same with the return trip. earlier last year when i went from portland to wenatchee WA i got 22-24.x on every all higway tank and that was with cc set at 80. before that was a trip down to monterey and back and even coming back up the winding parts of hwy 1 i still got 20 or better. i cant think of any all highway tank i got less than 19mpg.

The highest I have ever seen was when my wife drove for a tank of gas on our cruise to Santa Cruz last year. She was doing 65-70 mph with cruise control on and averaged about 22.5 mpg. I usually don't get better than 19 mpg on the freeway. In the city I'm about 15.5-16.5 mpg. I haven't ever been able to get above that and I do use 6th gear as often as I can when I'm on the freeway.

Ok, I am a very happy newish 8 owner. Got 700 miles. I seen 15 to 20 mpg in various driving situations.

The 8, as we know, has an engine that requires more RPMs that piston engines to get its power/torque. People used to gas engines, see an engine at 2, 3 or 4k RPM and assume it has power and just press the pedal. If the 8 is in top gear (that would be 6th), and you press the gas pedal way down, lots of gas is released but little acceleration occurs (well actually, I think very nice acceleration but not as much as in other RPM ranges and in other gears). Thus the effectiveness of gas consumption to acceleration is low. You might press the pedal half the amount and get 80% of the same acceleration. This general phenomenon makes people press the gas pedal more as opposed to shifting gear, putting the engine in a better gas/performance ratio and accelerating. Similarly, you could press the gas pedal less, get about the same acceleration but consume less gas. If you are used to a rotary engine, this would be more natural to you.

The above is based on the assumption that pressing the gas pedal does, in some way, correspond to more fuel being thrown into the rotary chambers without a computer somewhere in the middle serious tampering with the effect of pressing the gas pedal.

What do you guys think?

*ahem*

There's been tons of theories about this. I have a thread that was called 3250 - 3750 rpm is the key.

All I can say to your theory is... hmmmm...

uh.....i dunno. Back in the stone age when strange lumps of metal with hundreds of little holes in them called "carburators" roamed the earth and metered fuel I would have bought the theory 100%. Especially with an accelerator pump that gushed fuel into a motor when the throttle was depressed quickly. In this age of computer aided wizardry however, the pedal is often disconnected entirely from the engine. Now, a pedal is depressed to a certain degree which is assigned a corresponding value inside a tiny little black box. The magical engineering gremlins translate this number as a scale amount of desired torque. These same gremlins then converse with predetermined flow charts and graphs that ultimately decide that the best course of action is simply to pour gasoline into your spinny combustion chamber until enough exhaust is produced to turn your shiny chrome tips black; the ideal amount for power at any given RPM! I burned $12 of premium fuel in the course of 1 1/2 hours and about 18 miles last saturday on a trip through my favorite twisties. All I know is this, those engineering gremlins have managed to develope a correlation between fuel spent, and the size of my smile. I'm grinning ear to ear.

uh.....i dunno. Back in the stone age when strange lumps of metal with hundreds of little holes in them called "carburators" roamed the earth and metered fuel I would have bought the theory 100%. Especially with an accelerator pump that gushed fuel into a motor when the throttle was depressed quickly. In this age of computer aided wizardry however, the pedal is often disconnected entirely from the engine. Now, a pedal is depressed to a certain degree which is assigned a corresponding value inside a tiny little black box. The magical engineering gremlins translate this number as a scale amount of desired torque. These same gremlins then converse with predetermined flow charts and graphs that ultimately decide that the best course of action is simply to pour gasoline into your spinny combustion chamber until enough exhaust is produced to turn your shiny chrome tips black; the ideal amount for power at any given RPM! Close.

I call BS on the original 'theory'.

The accelerator pedal 'requests' more air to be allowed into the engine, by opening the throttle plate. More air cannot enter than leaves the engine (an internal combustion engine is basically a pump). At a given RPM (4000 for an example) there is a lower-than-ambient pressure in the intake manifold as the engine is 'hungry' for more air than your current throttle plate position will allow in. Opening the throttle plate lets in more air to 'satisfy' this hunger, and thereby raises the manifold pressure. As this increased volume of air flows towards the combustion chamber(s), the MAF (mass airflow) sensor determines that for X amount of air, Y amount of fuel is needed. This is the 'fuel mapping' that the engine computer does. You would think that it would be stoichiometric across the board (14.7:1 ratio), but in fact it may be slightly richer or leaner at different points. This is what the engine computer software (e.g. the ECU 'flash') does, in part. This increased volume of fuel & air causes the engine to accelerate above our example 4000 RPM to the point where said amount of fuel/air yields enough energy to spin the engine at a new speed (5000 RPM for an example) and no more. The fuel/air ratio stays roughly the same, controlled by the MAF/computer.

Since an engine is basically a pump, at a given RPM it can cycle only so much air in/out.

Therefore, when going up a hill and you floor it instead of downshifting, you're increasing the manifold pressure, sure. BUT, and this is key, if the RPM stays steady then the engine is only passing so much air through it. The amout of air limits the amount of fuel (due to the computer-controlled mapping ratio). Where it gets less straightforward is in the temperature differential of the air in/air out. There's all sorts of thermodynamics involved with the heating/expansion of combustion. However, the point is that there is not a lot of liquid gas gurgling unburned through your engine just because you depress the pedal without downshifting.

Edit: This also applies to the idea of reving to 3000rpm and switching off the ignition. As soon as the switch is off, no more fuel is being pumped into the engine. Any air that passes through the engine as it 'winds down' will evaporate any unburned fuel, thereby reducing (maybe eliminating) the possibility of a flood condition on restart.

oh c'mon man, that was much less funny....

uh.....i dunno. Back in the stone age when strange lumps of metal with hundreds of little holes in them called "carburators" roamed the earth and metered fuel I would have bought the theory 100%. Especially with an accelerator pump that gushed fuel into a motor when the throttle was depressed quickly. In this age of computer aided wizardry however, the pedal is often disconnected entirely from the engine. Now, a pedal is depressed to a certain degree which is assigned a corresponding value inside a tiny little black box. The magical engineering gremlins translate this number as a scale amount of desired torque. These same gremlins then converse with predetermined flow charts and graphs that ultimately decide that the best course of action is simply to pour gasoline into your spinny combustion chamber until enough exhaust is produced to turn your shiny chrome tips black; the ideal amount for power at any given RPM! I burned $12 of premium fuel in the course of 1 1/2 hours and about 18 miles last saturday on a trip through my favorite twisties. All I know is this, those engineering gremlins have managed to develope a correlation between fuel spent, and the size of my smile. I'm grinning ear to ear.

Okay I thought this was funny.

Ok, I understand that the air intake regulates throttle, vacuum and eventually gas consumption. But there has to be something that goes the change of RPM. If you simply create more vacuum the engine will stall because of lack of fuel (it takes some time for the more fuel to arrive). Essentially, this introduces what used to be called advanced timing in those antique carburator cars. Correct?

I can reword this to: does forcing the engine at low RPMs to produce more power result in a less efficient gas to power ratio? I understand the HP curve is about linear but is the gas consumption as well? There is probably a sweet spot (or range) per gear...?

???

Which brings us right back to "3250 - 3750 rpm" - search for that post and you will see the light, Grasshopper.

I agree with Batmobile - there is a direct coorelation between the amount of fuel burned and the broadness of the silly gring pasted on my face when driving the -8.

Stew

The above is based on the assumption that pressing the gas pedal does, in some way, correspond to more fuel being thrown into the rotary chambers without a computer somewhere in the middle serious tampering with the effect of pressing the gas pedal.
There's the problem - that assumption is completely wrong. In the olden carburetor days, the gas pedal was connected to the throttle - a blade in the airflow of the intake. You decreased vacuum, the engine sucked more fuel (aside from the accelerator pump giving an extra squirt when the throttle was moved). Air/fuel ratios were determined by the jets that controlled the amount of fuel that got sucked in to the engine in relation to the amount of air flowing by. The throttle controlled the AIR entering the engine, NOT the fuel. The fuel was determined by the carburetor jets in response to the air.

On a modern fuel-injected engine like the RX-8, the gas pedal is NOT connected in any way, shape, or form to the throttle. The gas pedal is connected to, and only to, the computer. Of course the computer is "tampering" - it's got 100% control! Even then - the computer controls the throttle, and fuel is injected in proportion to the air entering the engine. ALWAYS in proportion. There are feedback loops to keep the air/fuel ratios precisely controlled - there is absolutely no way that extra fuel is being dumped into the engine just because RPMs are low, it can't happen.

If you simply create more vacuum the engine will stall because of lack of fuel (it takes some time for the more fuel to arrive). Essentially, this introduces what used to be called advanced timing in those antique carburator cars. Correct?
No and No. The lag for fuel to arrive in response to air is measured in milliseconds. Timing refers to the ignition system firing the spark plugs in relation to the position of the piston or rotor - has absolutely nothing to do with fuel control.

I can reword this to: does forcing the engine at low RPMs to produce more power result in a less efficient gas to power ratio?
No. There will be differences in efficiencies at different rpms, but not for the reasons you've listed. Those differences will come down to tuning (intake/exhaust system optimizations) and mechanical (friction vs. rpm), and will make only a few % difference in the overall mechanical efficiencies. Give it up - your theory is falsely grounded, it's wrong! Sorry.

Regards,
Gordon

Gord (or anybody else) answer me this... I'm going n mph in my 8 in 4th gear. I shift into 5th and maintain the same speed. Which (if either) of those is more efficient in terms of mpg?

I'll talk more about it later but with my FIRST tank of gas I got 19.73mpg (city driving) or 252.5 miles in the city on 12.80 gallons of fuel.

I took a trip over the holidays , on the way back mainly highway and one tank of gas I used about 1/3rd of a tank intown I got 21 mpg ...I cruized anywhere from 75-85 mph . The wierd thing is , I filled up last Monday night , I usually get right at 200 mpg , I have 210 on this tank and have just under 1/4 of a tank left ...must be that oil change I made last Sunday !

Lower RPM, same speed = better fuel mileage,(less air flow+ fuel flow)

Danno, i dont think thats always the situation. something about the fuel mileage being a bell curve comes into play, i couldve sworn RG got into this once...

we need a lesson here about the difference between "open loop" and "closed loop" a/f mapping. luckily there is an excellent thread about this by Hymee here (http://www.rx8club.com/showthread.php?t=18833). go read that and then come back here with questions. basically here is the way i understand it.

below a certain trottle position and/or rpm (i have to re-read the thread myself to be certain) the pcm operates in closed loop which means it is always hunting for 14.7 to 1 a/f ratio. so if at a higher rpm you will be sucking more air so the pcm will add fuel to stay at 14.7. higher rpm = less mpg. in open loop it is entirely left to the maps in the pcm to determine a/f ratio. most of those maps are not looking for 14.7. those ratios can be tuned with a piggy back to what ever you want but leaning it out from our stock maps generally will increase power and mpg from what they were stock. so staying in closed loop at a constant speed and as low rpm as you can results in the best mpg. go into open loop and you will have a/f's that were best described by Paul Yaw as "PIG RICH" and your mpg will suffer as a result.

I guess I was being a bit simple.......:D

We could go into all kind of difficult discussions about the open/closed loop, target A/F ratios at different load, throttle positions, MAF Flow etc....and as a generality I would still say the same thing

All things being equal... my simplistic reply should suffice.....except for this tidbit i noticed on the weekend that my CZ was running in open loop above 77MPH because it thinks the TP is zero when cruize is on ?????

dannobre you were of course right i just wanted to point out to some otehr poster that there was much more to it than they were thinking.

except for this tidbit i noticed on the weekend that my CZ was running in open loop above 77MPH because it thinks the TP is zero when cruize is on ?????
because it is measuring throttle positon at the pedal and not at the throttle body? the pedal is linked to a potentiometer like device right? so anytime it in cruise it thinks trottle position is 0? but you are saying above 77mph. are you saying that below that it reads a throttle position?

No...It's still 0...but it's in closed loop below 77. It was running an A/F of about 14.0:1...in open loop at that RPM, same load.....14.6ish in closed loop 2MPH lower,. Why......... I guess that it was reading a different part of the table that didn't like something...so it went to open loop??

sometimes I wish it was as simple as the PCM in my MX-6

Lower RPM, same speed = better fuel mileage,(less air flow+ fuel flow)
Not quite - a gallon of gas contains a certain amount of energy, and a certain fraction of that energy makes it to the wheels to move a car down the road. Generally, gasoline engines and vehicle drivetrains are roughly 40% efficient in turning fuel energy into rear wheel power (Diesel engines are ~45% efficient, which is the simple reason why diesel cars get better gas mileage). To move a vehicle at a constant speed takes a constant amount of energy.

say you're driving a steady 60 mph. As a guess, it takes 25 rear wheel hp to keep an RX-8 at a steady 60 mph on level ground. It doesn't matter what gear you're in, 60 mph needs 25 rwhp. 2nd gear at 8700 rpm, you need enough throttle to generate 25 rwhp (would be a relatively small throttle opening). 3rd gear at 6000 rpm, you need enough throttle to generate 25 rwhp (a bit greater throttle opening). 4th gear at 4800 rpm, 25 rwhp, and a yet larger throttle opening. etc, etc.

As a gross generality, it takes a specific fuel consumption rate and associated air flow rate to generate 25 rwhp - again, that's regardless of what gear you're in to generate it! At high rpm in a low gear, you'll have a small throttle opening to only produce 25 rwhp, but at low rpm in a high gear, you'll have a larger throttle opening to allow the same amount of air to pass to produce that same 25 rwhp.

Say it takes 2 gallons per hour to generate 25 rwhp in general (which would be ~30 mpg for our example). Now to remove the generalities, if you factor in specifics like varying friction loads in the engine at different rpm, varying gearbox mechanical efficiencies in different gears, varying efficiencies in the intake and exhaust systems at different rpms, and varying fuel/air ratios at different rpms, and throttling losses, then you could see how it's likely that an engine will be slightly more efficient at lower rpm and higher throttle opening than at a higher rpm and smaller throttle opening to generate the same amount of power.

Testing generally shows this to be true - so from a fuel economy perspective, you're almost always better off to use the highest gear and lowest rpm to maintain your speed. The only time this wouldn't apply is if you need more than ~80% throttle opening, when engines typically richen the A/F ratio to avoid detonation (so fuel consumption will be relatively higher at full throttle at a lower rpm than part throttle at higher rpm to produce that same power demand).

Regards,
Gordon

Okay I thought this was funny.

what a guy

with Shell Vpower i get 24-26 at 80(long trips), with anything else I get 20-22. about 16-18 around town no matter what gas I use. 'L' flashed AT.

I always feel like I'm hurting the engine crusing at 90+ mph since it's over 5,000rpm. I know that it's not really bad for it, but it just feels strange crusing w/ the rpms that high. My last car was a 3rd gen rx-7 which at 90 mph was only doing around 3500rpm. Guess it will take me a while to get used to crusing at such high rpms.

..... My last car was a 3rd gen rx-7 which at 90 mph was only doing around 3500rpm. .....

Stock transmission/gearing ?

I always feel like I'm hurting the engine crusing at 90+ mph since it's over 5,000rpm. I know that it's not really bad for it, but it just feels strange crusing w/ the rpms that high. My last car was a 3rd gen rx-7 which at 90 mph was only doing around 3500rpm. Guess it will take me a while to get used to crusing at such high rpms.
Remember, that's the output shaft speed. The rotors are only doing 1/3 of that.

http://auto.howstuffworks.com/rotary-engine7.htm

I always feel like I'm hurting the engine crusing at 90+ mph since it's over 5,000rpm. I know that it's not really bad for it, but it just feels strange crusing w/ the rpms that high. My last car was a 3rd gen rx-7 which at 90 mph was only doing around 3500rpm. Guess it will take me a while to get used to crusing at such high rpms.

I'm still breaking in my 8 so I have not pushed her, but I agree...I tend to be a little scared considering 7K RPM was the most in my other cars. It will take a bit to get use to the 9.1K shift point...I'll learn fast I bet.

The best part about driving this car is running around town doing 6000 rpms !

The best part about driving this car is running around town doing 6000 rpms !even better part is letting off the gas and hearing the "turbine" engine spin down.

I pretty much do mostly city driving. So I thought I'd share some mileage numbers with you and see if anyone else has the same numbers.

After filling up with a full tank of gas, and doing city driving I got 88.7 miles before the gas needle reached the half-way point.

Would anyone like to comment.

Thank You.

Sounds like you got about 11 miles a gallon. Do you do a lot of real short trips?

Fill it back up tommorow and do the arithmatic, then let us know what it really is ok?

19.4 mpg since I've had the car. This also includes a track day which gave me 7.2 mpg :) Hell of a weekend at Road Atlanta. Max was 23.7 mpg. You can't really tell anything from "half a tank." Consistency is several tanks.

My standard deviation is 2.7 mpg, so I'm pretty much in control. Only out of control was one high (long road trip which was the high) and a track day which was the low. I'm relatively consistent around 19 - 20.

Posted by DavisRx8 in November and is right on what my car does (~16mpg)
Mixed Driving (50% hwy / 50% city)

By 1/4 Mark = 50 miles
By 1/2 Mark = 120 miles
By 3/4 Mark = 180 miles
Low Gas Light = 220 miles
Fill Up at = 240 miles

When I fill up at around 240 miles, my 8 takes between 13.5 - 14 gallons. Essentially, no matter how I drive, I will always get between 220 - 240 miles per tank before I fill up; unless I do all hwy driving, in which case I get between 260 - 275.

You can't measure MPG by using the fuel dial since it might not be linear. The only way to measure is by filling up, drive, measure miles and divide into the the gallons needed to refill. I get 15mpg.

Im at a half tank right now and i have 56 miles.. how shitty that? my last tank was 11.7 miles to the gallon..this car will not be around much longer.
robert

19.4 mpg since I've had the car. This also includes a track day which gave me 7.2 mpg :) Hell of a weekend at Road Atlanta. Max was 23.7 mpg. You can't really tell anything from "half a tank." Consistency is several tanks.

My standard deviation is 2.7 mpg, so I'm pretty much in control. Only out of control was one high (long road trip which was the high) and a track day which was the low. I'm relatively consistent around 19 - 20.

Now that's REAL data Lego. I track my mileage closely also, and although I only have 2,500 miles on the car, the average is just under 20 MPG. I classify myself as the average RX-8 driver. That is, run the revs up to near red line a few times on every drive, and on some sporty drives in the twistys, run it up there frequently. :)

Your track-day data point clearly shows the significant negative effect of hard driving styles on fuel mileage in the RX-8. This is the first time I've seen such hard data that demonstrates that so effectively. Thanks for sharing.

I pretty much do mostly city driving. So I thought I'd share some mileage numbers with you and see if anyone else has the same numbers.

After filling up with a full tank of gas, and doing city driving I got 88.7 miles before the gas needle reached the half-way point.

Would anyone like to comment.

Thank You.

Like some have already mentioned, the fuel gauge moves a lot quicker over the first half of your tank. You definitely have to measure over the course of an entire tank to get a realistic number, and calculate based on the number of gallons you fill with.

But I guess they don't let you drive much when you are in jail??? :p

19.4 mpg since I've had the car. This also includes a track day which gave me 7.2 mpg :) Hell of a weekend at Road Atlanta. Max was 23.7 mpg. You can't really tell anything from "half a tank." Consistency is several tanks.

My standard deviation is 2.7 mpg, so I'm pretty much in control. Only out of control was one high (long road trip which was the high) and a track day which was the low. I'm relatively consistent around 19 - 20.

7.2mpg at a track day??? Ouch...

I've been getting about 18mpg avg. on my 8 so far, so you are doing a little bit better than me. I have tracked mpg for every tank I've had on my car so far, but I haven't gone as far as putting the data on a pretty graph... yet. ;)

7.2mpg at a track day??? Ouch...




It was a Panoz event at Road Atlanta. 3rd and 4th gear all day. Seldom under 5K on the tach. Redline every time I went from 3rd for 4th. Hell of a day. Worth every $ spent on gas. :)

19.4 mpg since I've had the car. This also includes a track day which gave me 7.2 mpg :) Hell of a weekend at Road Atlanta. Max was 23.7 mpg. You can't really tell anything from "half a tank." Consistency is several tanks.

My standard deviation is 2.7 mpg, so I'm pretty much in control. Only out of control was one high (long road trip which was the high) and a track day which was the low. I'm relatively consistent around 19 - 20.
Ha! And I thought -I- was the only one obsessed enough to make a graphic of my mileage! :D

Let us know when you have some fillup-to-fillup figures, and how many gals you fueled up with. Then we'll have some numbers we can work with.

Typically I put in 13.7gal at a fillup and get around 240mi. That comes to about 17.5mi/gal.

Ha! And I thought -I- was the only one obsessed enough to make a graphic of my mileage! :D

That looks pretty near identical to what I've got... probably an average of 18.0-18.5, with lows near or just past 16.0 (at the end of the tank). I've experience what everyone else has experience with the half-way point. I noticed also that the 3/4 and 1/4 marks aren't even really 3/4 and 1/4 on the dial.. more like 13/16 and 3/16 (there is a wider space between full and "3/4" than between "3/4" and "half" - quotes used because I think we all realize by now they mean nothing :))

Edit: Your numbers are actually a little lower than what I've got... I don't think I've ever had in the 14s... I always fill up around 13.5 gallons and am almost always over about 205 when the light comes on.

Ha ha ha! I'm glad I'm not the only nut that logs every tank on a spreadsheet! I haven't graphed mine yet, but I would say it looks much like lego's graph but shifted down about 2 mpg and toss out the high mileage mark. I've got almost 14,000 miles logged to date, but I missed a couple of tanks at about 9000 miles.

It was a Panoz event at Road Atlanta. 3rd and 4th gear all day. Seldom under 5K on the tach. Redline every time I went from 3rd for 4th. Hell of a day. Worth every $ spent on gas. :)

I bet. I believe I've seen the video posted on another thread. Looked like a ton of fun. Hope your car is holding up ok. Never been on track with mine, but I dream about it rather frequently... ;)

@ my halfway i get about.... 90 miles with about 40% highway driving

I get about 21 mpg using 93 octane fuel. This is mainly hwy miles though. Around town I average 18mpg. Most I have got is 300 miles to a tank. I hear so many people say they get very low MPG. not sure why so low. When I drive hard I still get 200mile + from a tank

Ah, why not? Here's mine. The tall blip close to the start was from a 1500 mile trip. The rest is local driving, nothing over 50 mile one-way, nothing really heavily stop'n'go either though. 18.4 overall avg.

LOL, I just got my 8 but I already have my first fill up logged and I'll have a graph ready soon enough...LOL

Remember, I"m still breaking in my car and I shift between 3.25-4K and keep it under 5K, again...because I'm breaking it in.

With Citgo 93 (I got 252.5 in city driving @ 12.78 gallons = 19.75mpg) I was SO happy with my first tank, but I'm keeping it in perspective. I know once it's broken in I'll push her to 9K probably once or twice per tank, more if possible. What will that do to my numbers...I don't know, but I hope I got a good RX8 and I'm an efficient driver (YUCK, that just sounds wrong) so I'll be able to get 18mpg out of my 8.

Currently my needle is about 1/4 of an inch above half and I have 106.6 miles on my trip. Considering MOST people say they got better mileage with miles on the car, I think things are looking good right now. I can't stress "right now" too much here...

We will see...

PS. At least I can now say (some people here told me I probably would not get the EPA numbers) that for one tank...I GOT IT!!!

Ha ha ha! I'm glad I'm not the only nut that logs every tank on a spreadsheet!The attached should make you feel less nutty.

Enjoy,
Oranje

Oranje...nice numbers!

How would you say you drive your 8...conservatively, agressive, or something in the middle?

The attached should make you feel less nutty.

Enjoy,
Oranje

Oranje,

I think your numbers confirm somethign I have noticed.
The 8 gets worse gas mileage in cold weather.

I have found that to be the case and may have found a way to fix it.
My car flooded for the very first time during a cold spell here in AL.
Right before the episode, it was getting really rotten mileage.
Of course it took quite a bit of coaxing to get it started again...so to avoid a possible repeat, I started revving the engine to 3k RPM before turning engine off every time.

Since then, I have seen my mileage go up very significantly.
I still continue to take this step before stopping the engine and I am getting consistent 20 mpg or better.
Since the car richens the gas mixture when running rough, and it runs somewhat rough when rich or flooded, I think the ECU is getting into a sticky condition which it is not programmed to get out of.

Any thoughts folks?

Most of the miles are commuter ... about 70 miles RT on the days I take the eight out (only fair weather days) ... approx 65% of which are highway. The eight has been slumbering in the garage since just before Christmas.

I'd say I'm a mildly conservative driver.

Yeah I noticed the cold weather effect on the mileage, and chalked it up to Shell using a different cold weather blend.

[knock on wood] I've never experienced any hardstarts or a flooding experience, although I'm completely paranoid about it, even after a year, and never come close to shuting it off without it begin toasty warm.

Oranje

Hey, that sounds like my daily commute RT milelage, which is about 75/25 Highway/Local mix mode. I'm getting about 19-22 MPG since the M flash. I think that's not too shabby, but definitely not the best it can do.

Just a FYI, did you guys know that some of the G35 Coupe owners get about the same, it not worse mileage that some of us.

my mileage hasn't been a good one, i drive all city and average about 13-14 miles per gallon. my last tank was 174 miles till my light turned on, which showed to be 13.4 mpg. i live up a hill but i doubt that would kill my mileage this bad.

There is a PCM recalibration flash that you can request for free at a dealership (at least on a 2004 model). This flash supposedly makes flooding less likely and / or easier to overcome, and also supposedly slightly raises your MPG. I just got the flash, so I'm keeping track of how things are going. Previously, my MPG average was 18.8, and my average so far since the flash is 19.2, so it appears to have helped slightly.

I drive about 50/50 highway / city.

Just thought I'd share. I won't post my whole spreadsheet. :)

yeah....ok...I don't do math nor am I capable of understanding spreadsheet software. But I know this...the last good driving day of recent history, I started the day with the needle on empty...outta gas...I cruised up to the pumps, fished in the old bottomless wallet and reclaimed $12. Our piss gas was going for $2.16-gal. I drove out my favorite set of twisties and straightaways, hit a personal high top speed for this car and came home. Round trip....36 miles. Gas is empty. It doesnt take a graph or spreadsheet to know that sux. Ah well....worth it.

I'm just glad gas prices went down here in cali
I get about 15 mpg

I hope the first two months of owning my RX-8 are not a precursor of what's to come. The first problem was a cel that was apparently due to a engine coolant temp. sensor...easy fix, no big deal. Next was a dying battery. On cold mornings it would crank very very slow. You would think the dealership would have replaced it knowing it had been sitting on the lot for over a year.
Now it is my radio. I got in yesterday morning to go visit family and the speakers started making a sharp crackling noise. The stereo will come on but no music, no cd...nothing.

I know I will get flamed for this b/c it is a sports car and I am getting better mileage than a lot of people on here but the gas mileage sucks. I burned a half of a tank entirely on the interstate and got 18 mpg. The sticker says 24 on the highway. That is a 17% discrepency on a car that is brand new with less than 3,000 miles on it.

I got better gas mileage and had more power in my TII.....sorry for the rant but I think Mazda needs to keep a closer eye on quality control and put a little more into R&D. They have a great engine to work with but they are setting themselves up by pushing a car into the market before it is ready.

Again, sorry for the rant. I am sure I will be better tomorrow when it is fixed. :mad:

One thing is for sure, there are some 8's with horrid fuel economy, or bad/abusive drivers. Don't get me wrong...I think it's a little bit of both, but I hope one day you guys/gals with bad fuel economy get a fix.

Right now I'm very happy with my fuel economy, but who knows if that will last. Time will tell...

yeah....ok...I don't do math nor am I capable of understanding spreadsheet software. But I know this...the last good driving day of recent history, I started the day with the needle on empty...outta gas...I cruised up to the pumps, fished in the old bottomless wallet and reclaimed $12. Our piss gas was going for $2.16-gal. I drove out my favorite set of twisties and straightaways, hit a personal high top speed for this car and came home. Round trip....36 miles. Gas is empty. It doesnt take a graph or spreadsheet to know that sux. Ah well....worth it.


No way! Your saying that you went from full to empty driving 36 miles. Did it take 10 hours stuck in a traffic jam. I raise the bs flag. Damn I need to steel it for posts like this.

nononono...not full to empty (damn man, does $12 full up your tank?) according to my handy calculator here about 5.55 gallons at 2.16 a gallon. And there were no traffic jams...lots of passing in the twisties and constantly on the gas.....

I'm at 3,500 miles and have never even achieved ONCE the EPA city MPG of 18 MPG. My best tank ever was 17.3 and my worse was 15.3. I usually see a little over 16.

Okay, now for the "driving habits" question. Yes, I drive my 8 hard just like a stolen car. Every trip I make, it gets floored more times than I can count once it has warmed up.

Okay, now for the "driving habits" question. Yes, I drive my 8 hard just like a stolen car. Every trip I make, it gets floored more times than I can count once it has warmed up.

Rotormotion, don't get me wrong...drive as you wish but don't you want your 8 to last more than 45,000 miles? I'm new to the rotary engine and I think it is durable but raceing an engine "all" the time is not a good thing to do. Again, mabye it's just me...but that just sounds very harsh for the engine.

Again, don't get me wrong once mine is broken in I'll push her when I want...but every drive, daily...I just don't see myself doing that for the sake of the engine and fuel economy...

One thing to keep in mind if you want to know what your car will do per gallon under 'best' circumstances is that the motor has six jets, three per rotor. Under about 3750 revs only one jet per rotor is operating. Over about 3750 revs all six jets are pouring in fuel.

The more you drive 'like you stole it' the more gas you're pouring down a deep black hole. Don't blame the car. You want to see what the car can do, run a controlled test keeping the tacho below 3750 as much as possible. You might be surprised.

nononono...not full to empty (damn man, does $12 full up your tank?) according to my handy calculator here about 5.55 gallons at 2.16 a gallon. And there were no traffic jams...lots of passing in the twisties and constantly on the gas.....

From your other post that's 6.48 mpg. I still think that is obnoxiously low. Actually, quite amazing. :)

Rotormotion, don't get me wrong...drive as you wish but don't you want your 8 to last more than 45,000 miles? I'm new to the rotary engine and I think it is durable but raceing an engine "all" the time is not a good thing to do. Again, mabye it's just me...but that just sounds very harsh for the engine. Again, don't get me wrong once mine is broken in I'll push her when I want...but every drive, daily...I just don't see myself doing that for the sake of the engine and fuel economy...I hear what you are saying, and this is definitely not the first time I've heard this concern :) I sincerely appreciate your concern. All I can say is that I love cars and I love performance. Yes, I drive them hard, but I do follow a few rules. On a cold start I always wait 30 seconds--with my foot off the clutch--before I putting the car in gear. Just to make sure the oil pressure is up and circulating before I put a load on the engine or transmission. I never floor the car or go into the upper 50% of the tach until it is warmed up. I never bounce off the rev limiter. I don't do crazy downshifts. I always buy top quality parts and over maintain my car-->3,000 mile oil changes, coolant system flush every 2 years, routine gear oil changes, flush the power steering and brake system, buy top quality brake pads and tires, replace shocks at the first signs of decreased dampening (it’s amazing how many people never replace their shocks), etc.

Following the above prescription, I have 180K on my 92 Nissan Sentra SE-R. It was driven hard, but I followed the above rules. It didn't even start burning oil until 150K. Even now, I don't have to put in oil between oil changes and it still burns less than my 8. I've never had a mechanical problem outside of routine maintenance, normal wear parts, water pump at 140K, and front rotors at 170K. Oh, and a defective 5th gear repaired under warranty. I run the A/C once a week all year long and have never had to charge the system—during the summer it’s over 100 where I work, so if it were weak I would deal with it. I keep the engine clean. I even got 9 years off of my first battery. The first clutch and front brakes lasted 90K. The crappy factory tires made it 50K, but I was doing a lot of freeway driving back then. Many people tell me the car still looks new in some ways. And, I’ve annoyed past girlfriends by always parking the car in a ding-free spot across the parking lot. On an interesting note, a few years ago there was a lively discussion on the SE-R forum regarding whether the 92 had a rev limiter. So, I put the needle into the red for the first time to find out and a couple hundred in it pulled the power. So, actually, I’ve hit the rev limiter once, but never by accident due to driving style.

So, maybe I’ve got to redefine the stolen car thing. Yes, I’m the guy that always floors his car off the stoplight, and pretty much everywhere else, but I don’t break hard going into a red light. I don’t speed in parking lots or around town. But, if I’ve got an open left lane on the freeway, look out. I’ve made it from LA to the San Francisco Bay area—about 360 miles in 4 hours 30 minutes. That’s with one food stop and two gas stops—I discovered the SE-R gets 22 MPG driving near 100 MPH for prolonged periods. Normally it does about 28 on the Freeway. However, if there is an idiot in the left lane, I don’t tailgate or cut him off. I wait for a safe passing opportunity and then it’s C-Ya.

There’s a lot of discussion regarding the longevity of the Renesis. I don’t know how long it will last, but I’m going to treat it the same as my piston engines and we’ll see what happens…

With a full tank I can go about 250 miles. So I can get about 16 miles to the gallon HIGHWAY! So city I say 13-14 being generous. This sucks.

After six visits to the dealorship, who were actually great, this is where I stand.
I am still getting ten miles to a gallon. They replaced a thermostat to no avail. Sent the computer back to Japan and put it back in, no change. They now tell me they no longer have a Mazda rep. I called the Mazda hot line but they only refer me back to the dealer. I am out of options unless I find the right person to write to at Mazda or send a letter to. I can't afford to hire a attorney.

My MPG is getting better over time.
I have an 05 with 7600 miles.
I just filled up today and got 19 MPG.
That was 100% highway driving though.
I did not 'kill' the car on this tank, but I was aggressive.
My previous best was 17.3 which was the previous tank but wasn't 100% highway.

I spend $65/week in gas or more.
I would love to get better mpg, but I have to enjoy the car even if it costs me more in gas. My choice.

Howard: 10 mpg is unacceptable and insulting. I would call Mazda every single day until they had a game plan for me... and I do mean every day.
Good luck. Keep us updated.

-B

Just got a new 2005 RX-8. First 2 tanks my gas mileage has been around 12 mpg. I was thinking I was driving it too hard, but having owned a 1991, 1983, and 1984 RX-7 I have never seen this type of problems. I have been very conservative in the break in period, nothing above 6000 RPMs. What is the M-Flash and how do I get this done? :cool:

You are probably up to date on flashes if you just bought the car. I have recieved no benifit gas mileage wise from flashes and I have the latest and still get 10-11 in town. The sevice department has given up and I have been unable to get a response from Mazda. Good luck but you may be stuck.

Having been a private pilot for a number of years I can comment on a rich mixture. A rich mixture greatly reduces the Exhaust Gas Temperature (EGT). Exhaust gas can be as high as 1700 F. In other words it keeps the exhaust port section of the engine cooler - the extra fuel conducts heat out of the exhaust. This helps in expansion and contraction of the small rotary housing. Long term I could see how this would help the longevity of the engine. Rotary's have the problem of the the casing warping and apex seal failures. Looks like Mazda figured this out and did not want to apply a lot of stress on the engine in it's early life. However once the break-in period is over it should not be problem. I think the problem is that the software is broken, and not leaning out over time.

You are probably up to date on flashes if you just bought the car. I have recieved no benifit gas mileage wise from flashes and I have the latest and still get 10-11 in town. The sevice department has given up and I have been unable to get a response from Mazda. Good luck but you may be stuck.


My car has 7000 miles and I am also getting around 11 in town driving, using shell premium gas. I used to get 16 and I was pissed but now this is the last straw. I will be discussing options with my lawyer. This is unacceptable.

My car has 7000 miles and I am also getting around 11 in town driving, using shell premium gas. I used to get 16 and I was pissed but now this is the last straw. I will be discussing options with my lawyer. This is unacceptable.


Please let me know what he says. I am in this situation but have not contacted an attorney yet.

After researching the Internet it appears that the Lemon Law is not likely to be won for gas mileage. Mazda refuses to consider the 10-25% of those who are getting horendous mileage. My dealorship admits there is a problem but after five visits is out of ideas. I have actually been unable to talk to a representative from Mazda or contact one. I continue to get 10-11 mpg at 3500 miles in town. I am out of options but if I were someone buying a RX8 I would definetely try to find a way to drive it long enough to test mileage. I love the car but currently I am on a fixed income and I can't afford to drive it so it stays parked.

With the "L" flash I was getting 23-24 mpg but the car only ran okay in the midrange rpm's. It didnt't really wake up until 6K. However, with the "M" flash it now gets 19-20 mpg but will easily tear the rear tires up if I am not careful. Of course, I have other mods but I think the new flash will benefit most everyone. I measured a 20 hp increase at the wheels with the M.

Charles
I would appreciate more information on the M and L flash cards. I gather that the seem to adjust the idle from medium to low ( or lear fuel mixutures) can I just go by the dealer and request this changeover. My car is now in the garage getting a new main seal replaced and I wonder if I should have this done before picking it up. Would appreciate any input that I may get....thanks nico

hello everyone this my crapy story...i got my car about 4 weeks ago i filled up about 3 times now....first tank gave me 135..(T.T)***didnt mind due to the fact that i was reving and shifting at 5krpm just seeing how car was lol silly me****2nd tank gave me 165 shifting around 3k rpm...getting worried now....3rd tank 154 getting pissed now... total miles 454..i'm get about 9.8-11 mpg....and i have a 05 ....getting stats when i get flashed...***why meeeeee(>.<)***

Just a little over 10k miles with my auto. I've averaged 14 mpg. :mad:

If I would have known the mileage was going to be THIS far from "estimated" I never would have bought the car; even as much as I like the looks and handling of the 8, the MPG I'm getting is a joke.

As soon as my warranty coverage is over, I'm getting rid of this gas guzzler. Shit, I should have bought a used Viper, my mileage would be the same...

Filled up yesterday, got 21.56 MPG. Lovin' it!!!!

05 with 8600 miles.
My MPG is directly related to how I drive.
I have a long ride to work so I carefully tested my highway MPG on the last 3 tanks.
Same gas station. Pumped my own. Same pump. Same procedures.. etc..
I averaged around 19.5 (19.3-19.7 was the range)
During local driving if I rev the motor a lot, I can almost see the gauge moving.. haha no kidding.
I do not have local numbers to post. I would only be guessing... but it is much much worse.
(12-14 maybe)
-B

WOW, i suppose you are shifting out of first gear right? =D

Maybe your PCM, or your MAF is defective. There's probably not much you can do without going to the dealer. Unless someone is stealing your gas!

I know there are many threads on here about bad gas mileage -- I promise this isn't one of them.

Just traded my 04 sports MT for an 04 GT MT. got it MON night.

Driving to work TUES (16 miles) had a 1/4 tank.
Got in it to leave TUES afternoon and light came on (all gone!)

filled up and set trip.
have 30 miles on full tank and Im already down almost to 3/4.

what could be wrong? Just some suggestions before I carry it in to dealer to let them check.

do you have a leak?

Isn't the fuel system highly pressurized? if there was a leak, wouldn't it be REALLY obvious? (dunno, just asking)

I know there are many threads on here about bad gas mileage -- I promise this isn't one of them.

Just traded my 04 sports MT for an 04 GT MT. got it MON night.

Driving to work TUES (16 miles) had a 1/4 tank.
Got in it to leave TUES afternoon and light came on (all gone!)

filled up and set trip.
have 30 miles on full tank and Im already down almost to 3/4.

what could be wrong? Just some suggestions before I carry it in to dealer to let them check.
First, you need to determine the gas mileage you are getting by calculating your actual mileage. Gas gauges are notoriously inaccurate and that's what the dealer will tell you if you use the gauge to justify a gas mileage complaint. If your calculations show gas mileage of around 18-20mpg mostly highway travel, that's probably the best you can expect to get and Mazda will not do anything about it.

So, before you take it in to the dealer and complain about the gas mileage, you better run through a half dozen tankfulls at least and document the mileage. You know, miles traveled divided by gallons added to tank? Keep receipts and present all this to the dealer with the calculations or your complaint will not be considered credible.

Fuel gauges are not THAT innaccurate....30 miles on 1/4 tank? I've never seen a gauge that far off. 50 miles for the 1st 1/4 tank, 60 miles for the 2nd 1/4 tank, 70 miles on the 3rd 1/4 then about 50 miles until the low - fuel light illuminates; that's the standard way my car's fuel gauge reads. 92 Octane - with 89, add about 20 to the first 1/4, 15 to the 2nd..

I'll add my current fuel economy stats:

I have about 1,700 miles on my baby and I've gotten 19.8, 19.4, 18.9, 18.9, 19.2, & 18.7 mpg. Most of my driving is in the city 75% with about 15% highway miles and 10% fun driving. The last tank that came in at 18.7 the fun percentage was more like 35%.

So, considering that I hear these 10-13mpg RX8 owners out there...I'm VERY HAPPY with my fuel economy. Heck...If I drive her easy I can get 19+ without a problem. With some fun I'm still hitting over 18.5.

I hope it lasts...but I really worry that some RX8's have some MAJOR fuel consumption issues or their drivers are beating the heck out of them.

Everyone hitting numbers under 15 should get together and document the problem. Have other people test their cars, take video, etc....prove your story to Mazda or the dealership so they wont say it's YOU that is causeing it.

I was very worried about the stuff I would here on this website about fuel economy but so far after 6 fill ups....those complaints dont' apply. THANK GOD!!!

Good luck to all of you that are going through this!

I have 4500 miles on my 8 and I routinely get over 20mpg and I take it to 7k RPM's at least twice a day. I actually am very proud of the gas mileage, I don't even worry about it anymore because it's proven to be a very good vehicle for a narrow focused sports car.

I have 4500 miles on my 8 and I routinely get over 20mpg and I take it to 7k RPM's at least twice a day. I actually am very proud of the gas mileage, I don't even worry about it anymore because it's proven to be a very good vehicle for a narrow focused sports car.

I found myself saying the same thing. Then one day, I stopped to think about it, how it is totally insane to convince oneself to be happy to average 20 to 21 MPG hwy. It is somewhat analogous to an illegal organization, such as the Japanese yakuza, rationalizing an honor system for behaving honorably while conducting criminal behavior.

I agree...getting 18-19+mpg in a sports car is just fine in my book....I just wish we could use 87 instead of 93 (we don't have 91 in my area).

OH...and I mean in the city, not highway. I actually can't wait to take a trip in my 8 to see what it can do in the highway.

18-19+ is great for a sports car in the city....but highway should be well over 20mpg or else that would be a big disapointment.

Sounds like you got a good one. I think I got a good one too. But, see again, I can't believe I'm saying that.

Here's an interesting write-up on the topic courtesy of MSNBC.COM. Puts our mileage figures in perspective.

By George Lewis
Correspondent
NBC News
Updated: 7:41 p.m. ET March 8, 2005


We've all seen them — those estimated gas mileage numbers posted on new cars. Numbers that turn out to be phony, according to the American Automobile Association (AAA), which has released its own set of numbers for consumers.

"We give them our estimate, our real world estimate, because our auto reviewers aren't very confident in that EPA number," says AAA spokesperson Mantill Williams.

Neither are many motorists.

"It's not accurate on the highway speeds," says one.

"I'm sure they take it downhill with the wind behind you to make it sound good," says another.

There are some huge differences between the EPA mileage estimates and the AAA numbers. For instance, a BMW Z4, rated at 21 miles per gallon city and 29 highway by the EPA gets only 14.5 miles per gallon in the AAA tests.


The popular Chrysler PT Cruiser, also rated at 21 city and 29 highway by the EPA, got a AAA average of 17.5 miles per gallon.

And the GMC Sierra, with an EPA rating of 16 city and 21 highway, got an auto club number of 15.3 miles per gallon.

The problem, says AAA, is that the federal government does not test cars in real world situations and doesn't factor in things like running the air conditioner or driving in stop-and-go traffic. Most tests are conducted in labs with the engines already warmed up, the speed kept below 60 miles an hour.

Now, two members of Congress have introduced legislation to change EPA testing methods.

"They have a statement that says, 'your actual mileage may vary,'" says the bill's co-author Rep. Rush Holt, D-N.J. "They should say, 'your actual mileage bears no relationship to these numbers in the window.'"

The EPA released a printed statement saying it's re-evaluating its fuel economy calculation to provide consumers with more realistic information. The idea: To eliminate that other kind of sticker shock, when you find your new car doesn't measure up to the government's mileage figures.

© 2005 MSNBC Interactive
URL: http://www.msnbc.msn.com/id/7128017/

You beat me to it! :D

Sounds like you got a good one. I think I got a good one too. But, see again, I can't believe I'm saying that.

Yeah, I'm very greatful because I think I got a good one too. Keep in mind I have the base 6spd which is lighter (so I'm told) so maybe that is helping out a bit. But...I understand what you are saying...by this day and age we should be getting low 20's in sports cars as the avg.

Go48...Amen to that, thanks for posting! On my sticker window the EPA stated 18/24 for my car but also had a disclaimer that said they observed anything from 15/28 so if 8 drivers are in that range...they really can't complain too much.

I know there are many threads on here about bad gas mileage ...
You're probably having too much fun! My '8 is coming up on 50,000 miles and mpg averages 19.7 with low 14.3 and high 21.1. I've recorded every tankful and almost always drain the tank down to 14.3 to 14.5 gallons. Best mileage is when it's sub 60f ambient, clear traffic, cruise control at 80-85MPH, and NEVER, shift above 2,700, which is way hard to do in this car. Give that a try for a couple tanks and let us know. (Don't think this will work for you, unless you do > 95% freeway driving with trying to stay in 6th when coming up on gridlocks. If you're street'n this car, don't expect too much in the MPG column.)

This is my 4th RX- and I was really looking forward to the Renesis technology delivering more MPG than I had before, which averaged 21-22. Thinking that a mild street port after the warrantee runs out will get me back to what I was getting, before, plus an extra 20-30 hp :D . I still think this car is a great hybrid candidate (yeah, blasphemy, I know). I'd more than exchange an extra 400 lbs for 100 more hp and 100 lb/ft of torque from 0mph all the way up the rev range!

Owned two weeks and this is what I get. The mileage sucks. :mad:

Mazda RX8
Date Start End Dist Gallons MPG
4-Mar-05 100 238 138 12.33 11.19
10-Mar-05 238 377 139 12.9 10.78

It had better get better. There's not enough power to justify this mpg.
I'm 39, and I drive normally. My 2002 VW GTI got 20 to 25 mpg.

Owned two weeks and this is what I get. The mileage sucks. :mad:

Mazda RX8
Date Start End Dist Gallons MPG
4-Mar-05 100 238 138 12.33 11.19
10-Mar-05 238 377 139 12.9 10.78

It had better get better. There's not enough power to justify this mpg.
I'm 39, and I drive normally. My 2002 VW GTI got 20 to 25 mpg.
Take it to a dealer and show the service people these numbers. It probably isn't going to get much better with time. Driving style can have an impact on fuel mileage, but not to this extent IMO.

The car is new to me. Build date 06/03.
the dealer told me that ALL updates, flashes etc had been done.
I expected 15mpg city, 20+ highway.
I just drive normally - breaking the car in right now, so no "racing" is going on.
I'm going to keep documenting it, but I'm afraid I might have purchased a problem child. :(
This HAS to get better.

Just as a note. It was 70 degrees and sunny yesterday and my daughter and I went for a drive in the S2000 - top down of course. Nothing but winding, twisty back roads for close to 200 miles. Driven pretty hard with lots of VTEC action, but not qute as hard as I had been driving by myself. MPG for the day: 26.0 on the nose. Commuting to work and back with lots of stop and go, I get between 21 and 23mpg. Not bad for a 240hp sports car - but it does need premium.

My daily driver right now drinks premium too and only gets 14-15mpg. I was thinking of getting an 8 for the daily grind. These poor numbers everyone posts has me re-thinking that :(

Dennis

Well, folks, I just have to report my personal best for mileage. Just got back from a trip from San Antonio to New Orleans. 10 hours driving, with me (6'4"), my wife (5'7") in the passenger side, and my son (6'1") behind her. No one complained too much. And, for the first time EVER in any automobile I have driven that distance, my back and neck feel great. Used to get very uncomfortable in the RX-7, Nissan Pathfinder, and Isuzu Trooper. Now, to the mileage.

I desperately wanted to exceed my personal best on miles driven on a tank. but unfortunately in both instances where the mileage was great, I was heading into the bayous, where gas is nowhere to be found. I had to fill up with a quarter tank remaining. But holy sh*t, 280 miles and still a quarter tank left? Can't be possible! Anyway, here are the best numbers (worst on the trip was 20mpg).

Miles gallons MPG
280 11.49 24.36
307 13.01 23.57

This was primarily cruising at between 70 and 80MPH on an incredibly boring straight, flat section of highway (I-10). I did use the cruise control more on the first trip than on the way back. Anyway, 24.36 is my best mileage recorded on over 20 years of rotary engine ownership. That being said, I occassionally got 23 in my 2nd gen RX-7 on long road trips, so the 30% improvement the Renesis was supposed to achieve is a bunch of BS. Anyway, I was happy to get what I did, and thought I'd report it.

BTW, I used 89 octane, as I almost always do.

My Gas Mileage seems to have gotten much better after I had my car worked on. I had Mazdaspeed lightweight flywheel installed at the dealer and they gave me the new "N" Flash. I don't suppose a lightweight flywheel would help much with MPG so I attribute this increase to MPG to the Flash:



Miles Gallons MPG Date Notes

258-- 13.161-- 19.60-- 06/04/04
199.1-- 12.751-- 15.61-- 09/05/04
204.8-- 13.00-- 15.75-- 09/14/04
190-- 13.00-- 14.61-- 12/08/04
194.6-- 13.312-- 14.61-- 12/18/04
187.6-- 11.622-- 16.141-- 01/06/05
213.7-- 13.294-- 16.07-- 01/13/05
206.8-- 12.919-- 16.00-- 01/17/05
176.6-- 11.761-- 15.015-- 03/05/05

After LightweightFlywheel/body kit/suspension/ "N" Flash

227.8-- 13.114-- 17.37-- 03/10/05 ECU might still be in learning mode
265.3-- 13.276-- 19.98-- 03/19/05


On my last tank you see here it was kinda weird. I only got about 105 miles at the halfway mark on the gas tank, this was with alot of city driving. At the half way point I went cruising on the weekend, I hit about 210 miles at 1/4 tank left to my amazment, but then the last 1/4 tank to empty light I only got about 55 miles out of it. Not sure that our gas meter is all that accurate.

Well, folks, I just have to report my personal best for mileage. Just got back from a trip from San Antonio to New Orleans. 10 hours driving, with me (6'4"), my wife (5'7") in the passenger side, and my son (6'1") behind her. No one complained too much. And, for the first time EVER in any automobile I have driven that distance, my back and neck feel great. Used to get very uncomfortable in the RX-7, Nissan Pathfinder, and Isuzu Trooper. Now, to the mileage.

I desperately wanted to exceed my personal best on miles driven on a tank. but unfortunately in both instances where the mileage was great, I was heading into the bayous, where gas is nowhere to be found. I had to fill up with a quarter tank remaining. But holy sh*t, 280 miles and still a quarter tank left? Can't be possible! Anyway, here are the best numbers (worst on the trip was 20mpg).

Miles gallons MPG
280 11.49 24.36
307 13.01 23.57

This was primarily cruising at between 70 and 80MPH on an incredibly boring straight, flat section of highway (I-10). I did use the cruise control more on the first trip than on the way back. Anyway, 24.36 is my best mileage recorded on over 20 years of rotary engine ownership. That being said, I occassionally got 23 in my 2nd gen RX-7 on long road trips, so the 30% improvement the Renesis was supposed to achieve is a bunch of BS. Anyway, I was happy to get what I did, and thought I'd report it.

BTW, I used 89 octane, as I almost always do.


Interesting... wondering if you had any Overheating issues w/ long distance driving. I read from other sites how long trips ended up w/ some coolants evaporating.
Wondering if you had any experiences like this, esp. driving in warm/hot weather, or Not. If anyone else has input too, would be great. Thanx.

Interesting... wondering if you had any Overheating issues w/ long distance driving. I read from other sites how long trips ended up w/ some coolants evaporating.
Wondering if you had any experiences like this, esp. driving in warm/hot weather, or Not. If anyone else has input too, would be great. Thanx.

I drove 1177 miles from Washington State to Irvine for Sevenstock7 and had no overheating problems. It was over two days, but we ran at classified speeds part of the time in Cali :rolleyes: I remember hitting some MPG's in the low 20's also. My highest was 23+ something that trip.

I drove 1177 miles from Washington State to Irvine for Sevenstock7 and had no overheating problems. It was over two days, but we ran at classified speeds part of the time in Cali :rolleyes: I remember hitting some MPG's in the low 20's also. My highest was 23+ something that trip.


Cool... I plan on taking a 3 day 2,000 mile road trip from the Midwest to Cali in May, when it'll be rather warm.
Anyone else w/ a similar or longer road trip on their Rotary??

Just took my first real extended drive. With cruise set at 70 in the flats and no traffic, got 23 mpg. The second tank included 2 trips over "the grapevine" (mountains N. of LA) at (ahem) higher speeds, and also being stuck for a couple of hours in LA traffic. Mileage? 23 mpg. LMAO. This last tank promises to be even better; I've got close to 300 miles and still not quite to the gas light. Might have been some tailwind.

At least it finally lived up to its 24 epa highway rating for me. Around town I usually get 15 or 16.

So you guys are getting about 220-230 Miles to a 16 Gallon tank?


Andrew

I wonder. Obviously there are physical reasons why the rotary engine gets relatively poor gas mileage when compared to a piston engine (don't ask me to go into detail about this...just know what I've read here and there), but there is a WIDE discrepancy between mpg between different '8 owners.

Some reasons have already been discussed and are still being debated. For instance, I'm not so sure about the "always keep it under 2700 rpm" theory by the guy who is getting 21 mpg max. I tried shifting around 3500-3800 and got a little over 23 mpg on nearly all highway driving on a roadtrip, which INCLUDED 135 out of 230 miles of stop & go highway traffic. Man, that sucked huge.

I wonder how much the following possibly overlooked factors have to do with it? Your thoughts?

* Tires? Are those who are getting 12 mpg using winter tires, and those getting 24mpg using stock (or vice versa, whatever).
* Altitude? Does the '8 perform better in low/high altitudes
* Terrain? Are those of you who are getting great mileage living in the flatlands? (I am)
* Rider weight? How much difference would it make over the course of a tank for the '8 to be pulling a 130lb driver vs. a 230 lb. driver?

I think those point are contributors but I cant imagine that they are the reason for the large discrepancy between results. Someone over hear has found that if the throttle is moved more than 20% then the ECU moves into Open loop. If you spend most of your time in open loop then you are going to get bad mileage. So its still possible to rev reasonably high so long as you dont dump the throttle.

Andrew

PS are my calculations correct in my previous post?

PS are my calculations correct in my previous post?

("So you guys are getting about 220-230 Miles to a 16 Gallon tank?")
Not sure where you got those numbers, but most are reporting considerably better mileage than that. My average mileage for the first 3,100 miles is just under 20mpg. So that would equate to 320 miles per tank. Mostly open road driving with maybe 10% what might be considered city driving.

Are you really asking how many miles before the warning light comes on? If that's the question, I typically get 250-270 miles before the light comes on, which equates to about 13.5 gals if you fill up immediately.

I had the latest flash done on my 04. Before I was averaging around 19.5 mpg and post flash I'm getting 21.5 mpg in mixed driving. Car has 5200 miles on it, driven somewhat aggresivly and usually use premium, sometimes midgrade. Also, I don't think we have ethanol mixed fuel around here. I wonder if that could possibly affect the numbers?

I've got an 04 6MT with 2,000 miles on it. It has the 'N' flash.

So far, I'm getting 200 miles per tank (fill up takes 14.5 gallons).

If it doesn't improve dramatically, I'm going to have a severe case of buyer's remorse!

Lack of ethanol is supposed to help I've heard... I was reflashed to N a couple of weeks ago, and initially pulled about 17.3mpg....an improvement of almost 2 mpg for me. This second week, no go....182 to the fuel light. Oh well.

I was originally getting about 13 miles to the gallon and I usually drive about 60% city/ 40% hwy. I started keeping the rpms at 3,000 or under and that number jumped up to about 15.9 miles per gallon. After getting the improved spark plugs installed and the N flash, my car seemed to run much smoother and was more responsive. Right now, I am at about 223 miles with about 2 clicks left on the last 1/4 of the tank. I can probably squeeze another 20 miles out of it, which would put me close to 250 miles. Plus, I just hit 3,000 miles and I have heard some speculation that this might be the end of the break in period (engine runs rich during the break in), even though my service advisor says that officially, Mazda says there is no such break in period. At this point, if I could get 18-20 mpg, I would be ecstatic.

My 2004 Mazda RX8, Build date 6/03. 6 Speed

This really sucks. The old Lamborghini Countach got 11mpg.
The rx8 is nice, but it's no lambo... :mad:

Just filled up today, and I'm back to my normal driving routine. But this time I got 22.4 MPG, which is about 3MPG better than my usual. I'm thinking that it has to do with the fact that I'm now leaving for work at 5:45 instead of 7PM, and I'm missing all of the stop-and-go traffic.

Oh, yeah, and Mr. Stupid here ran out of gas over Easter weekend. 5 miles from home (3 from the gas station). I'm a little perplexed, because the needle was in the same spot where it has been lots of time before. Fortunately a helpful guy pulled over and gave me a ride to my house to get a gas can.

Can running out of gas cause your car to subsequently sip fuel a little more conservatively? :)

I drove 1177 miles from Washington State to Irvine for Sevenstock7 and had no overheating problems. It was over two days, but we ran at classified speeds part of the time in Cali :rolleyes: I remember hitting some MPG's in the low 20's also. My highest was 23+ something that trip.

claassified is right!!;) nbut your highes was 24.1 or something is what i remember. on one of the tanks where i got 23.99 i remember yours being over 24:D and you didnt believe me setting out:D

What's going on here? Why am I getting 12 mpg WHY WHY WHY?
I KNOW I did not buy an economy car, but this pisses me off.

I bought an 04 for the rebates and the great deal, but I think I got suckered. I was worried about an early build - 6/03. i was probably right.

And when I ask any Mazda "official" about it, they say,
"It depends on how you're driving it".

You know, mr MAZDA MAN, you're right, maybe I should stop driving at 9000 rpm on my daily commute through Brooklyn. Maybe I should stop racing around Ocean Parkway at 125mph. Maybe I should stop towing a trailer with the air conditioner on. Maybe you should look at me- I am a 39 year old man who simply DRIVES the car NORMALLY, and gets gas milage worthy of a HUMMER towing a battleship.

MAYBE YOU ALL SHOULD ADMIT THAT THE ROTARY IS A FLAWED CONCEPT AND THAT THIS CAR SHOULD HAVE A 4 CYLINDER TURBO WITH LOTS OF POWER AND A REAL 22MPG. MY VW GTI HAD THAT. It also handled like a wet noodle, but that's another topic.

you appear to have issues. take your car in and demand that they do an mpg drive test. they will have to keep the car a day or 2. my car is an early build-earlier than yours - and i get 17-18 around town. your bolded statement above is incorrect.

you appear to have issues. take your car in and demand that they do an mpg drive test. they will have to keep the car a day or 2. my car is an early build-earlier than yours - and i get 17-18 around town. your bolded statement above is incorrect.

I have gotten ten mpg since I got my car. They have tested the mileage and got 11mpg, but they could not do anything and MAzda has no interest in resollving the problem.

hi howard long time no see. did you try to lemon your car?

howard

do you know anyone with a canscan device? Can you log your a/f ratio? that would be a good start in knowing where your issue might be.

see my thread in the gulf forum about improving mileage, see if that helps

zoom44, That's the first real yelling I've done about the car. I do like it, just frustrated.

I will take it in to service, but I am so angered by the "It must be the way you drive" comments from anyone at Mazda that I have asked.

I made a point to find company people at the Mazda booth at the NY auto show, and they were wagging thier finger at me, telling me to drive more slowly, don't let it rev so high.....

hi howard long time no see. did you try to lemon your car?

No. I don't think it would be easy or even possible from what I have read on the Internet to Lemon a car for fuel Issues.
What really needs to happen is a class action suit by the small percentage who have the extremely low mileage. It would never go to court and Mazda would settle but everyone would probably get only a small amount of what they loose in milage over the life of the car. In any case that is way over my head.

howard

do you know anyone with a canscan device? Can you log your a/f ratio? that would be a good start in knowing where your issue might be.

see my thread in the gulf forum about improving mileage, see if that helps

No I don't really know anyone who messes with cars anymore. I used to years ago.
I'll take a look at your info. Thanks

has any of you who are getting crappy mileage checked your plugs to make sure one of them hasn't fouled?

No. I don't think it would be easy or even possible from what I have read on the Internet to Lemon a car for fuel Issues.
What really needs to happen is a class action suit by the small percentage who have the extremely low mileage. It would never go to court and Mazda would settle but everyone would probably get only a small amount of what they loose in milage over the life of the car. In any case that is way over my head.

manufacturers aren't allowed to make claims on mileage that's why the epa does it. you'd have to sue the epa and there's not a chnace in hell of getting them to change their flawed estimating procedures, they don't even drive the cars, the run them and measue the exhaust and then extrapolate figures from the readings.

what it'll take is another nader, someone who will stand up and fight back and amke them change the whole thing.

manufacturers aren't allowed to make claims on mileage that's why the epa does it. you'd have to sue the epa and there's not a chnace in hell of getting them to change their flawed estimating procedures, they don't even drive the cars, the run them and measue the exhaust and then extrapolate figures from the readings.

what it'll take is another nader, someone who will stand up and fight back and amke them change the whole thing.

The EPA establishes the test prodedure and the conversion factor (in the test they cars get much better mileage than the window sticker shows). The testing routine is published and the automakers do their own tests. The tests are usually done on a pre-production car.

The EPA can (and does) spot check to make sure the automakers are doing it properly - but I am sure they have too small a budget and there are way too many cars for them to re-test them all.

There a tons of problems with the tests - mostly it is outdated. You can contact the EPA to "object" to the gross error in the RX-8 mileage you get VS sticker and see if they plan on testing it themselves or not. Maybe if enough people do, they will.

It also could be the Mazda did the test fair - and the 8 just happens to do well on this test. Hybrids, for example do REALLY well on the test - a lot more so than they do in real life.

Interesting to note: A manufacturer can't give out a mileage estimate other than EPA - by law. So Toyota (and Honda) know their hyrbids will dissapoint most consumers but they can't tell them. So even if Mazda knows the stickers not correct, by law that is what they put on the windows.

The testing produceedure itself is really old and flawed. The BlueWater Network (a bunch of tree hugging hippies :D) has petitioned the EPA to fix its testing and labelling proceedures. In this case, they are right.

http://www.bluewaternetwork.org/

Here is how they test a car:


The gas mileage estimates are based on results of tests required on new motor vehicles (cars and light trucks). Designated pre-production prototypes of new models are driven by a trained driver on a dynamometer, an instrument similar to a treadmill. The same tests are performed on each vehicle tested, following approved procedures, as described in the Federal codes or regulations. These procedures ensure that each vehicle is tested under identical conditions, therefore, the results can be used with confidence to compare similar cars. Two different tests and gas mileage estimates are done for each vehicle tested; a city estimate, designed to represent typical everyday driving in a city, and a highway estimate, to represent driving in a rural setting. The tests measure the waste
substances emitted from consuming the fuel, not the actual fuel consumed. From the measurement of emissions, EPA can estimate the miles per gallon achieved by the vehicle on average.

The test used to determine the city estimate simulates a 7.5 mile, stop-and-go trip with an average speed of 20 mph. The trip takes 23 minutes and has 18 stops. About 18 percent of the time is spent idling, as in waiting at traffic lights or in rush hour traffic.

The test to determine the highway estimate represents a mixture of 'non-city' driving. Segments corresponding to different kinds of rural roads and interstate highways are included. The test simulates a 10 mile trip and averages 48 mph. Me test is rue when the engine is warmed up and with very little idling time and no stops until the end of the test.

To make the numbers on the labels more useful for consumers, EPA adjusts the laboratory test results to account for the difference between the controlled laboratory conditions and actual driving on the road. The city estimate is lowered by 10% and the highway estimate by 22% from the laboratory test results. Experience has proven that these adjustments make the nfflcage estimates on the labels correspond more closely to the actual gas mileage gotten by an average driver.

Note the speeds. I would hardly call a 48mph average speed with no stops "highway" driving. Of course there is no wind resistance, etc. They also don't test with the A/C on, lights on, etc. So the load is at the minimum on the engine. The control the temp at 75 degrees, so your cold mileage will almost always be worse.

So be mad at the EPA for having a bogus proceedure, with out of date speeds and trips. The manufacturers have to follow it, even if it is wrong. Now of course, they could fudge the number to make a car look better than it is - but I think it is mosly that (like the hybrids) the 8 may just do a lot better on these exact tests than they do on real roads - so the larger than normal difference in real-world VS EPA numbers.

Keep in mind the manufacturer's play games too. The rules say if the test car has a shift light or ecomony indicator the "driver" has to do his/her best to follow it. So they will put shift lights (like the Corvette's 1 to 4 shift light) in the car to boost the mileage numbers. Since all hybrids have economy indicators, they try to keep them in the "green" and still do the test. Most folks would never drive like this. Really slow starts and acelleration and slow, coasting stops. Not even close to real-world.

Dennis

What upsets me most of all is the VARIATION in MPG figures.
Many are claiming 20mpg.
I am getting 11mpg.

has any of you who are getting crappy mileage checked your plugs to make sure one of them hasn't fouled?

I believe if it were fouled you would get a CEL or very poor pickup. I get neither but I get 10mpg in town. Now I have had a recent discovery. I went out of town on a trip this last weekend. Something I seldom do. Most of my driving is in town. I set my cruise at 78 for 150 miles. I got 20 mpg. I was chocked. I drove the next 150 without cruise and I got 15mpg. I believe that the problem lies in the way I accelerate or else in something mechanically related to that. I never expected to get 20mpg on the highway and I am absolutely thrilled. I wonder if all the drivers getting 10-12 in town drive almost exclusively and the others with better mileage have either mixed or highway driving. Also the cruise control obviously makes a huge differrence, although I did accelerate as normal getting to 78.

Don't get me wrong I love my 8 but the gas goes real quick if I get ten mpg I would be surprised.But i bought a sports car so I deal with it. I drive it like it was designed to red at 9,000 so as I go from 1st to 2nd just cruising I naturally shift about 4,500 to 5500 rpm and thats just riding along any kind of fun driving is much higher revs, but my 69 z-28 got under 6 mpg and my near stock 71 vette with a 454 got 8 so I don't think its out of line.
today I filled it dead empty and spent 35 bucks made me blink but if i wanted gas mileage I would drive my wifes malibu...............................
Oh and to avert any questions my car has been in the dealer 17 times in less than 12,000 miles and I am person non Grata after they left the bolts out holding the under engine cover panel after changing a fog light that went bad. it came off and flew into a million shreds on the interstate 5 miles away from the dealers I was super pissed at them it could have killed someone behind me.I now go to a different dealer for service(recalls)

all these threads with mileage and i never even probably calculated mine to test lol i think i usually get about 240 when the low fuel light comes on don't know how much that translates too i usually end up putting back in at least 12 - 13 gallons.

...Now I have had a recent discovery. I went out of town on a trip this last weekend. Something I seldom do. Most of my driving is in town. I set my cruise at 78 for 150 miles. I got 20 mpg. I was chocked. I drove the next 150 without cruise and I got 15mpg. I believe that the problem lies in the way I accelerate or else in something mechanically related to that.....
Howard, good to see that you have finally managed to get a different mpg number. Your mpg issues have been pretty well documented on this board. I suggest some more "testing".

A good excuse to go on another Road Trip... ;)

all these threads with mileage and i never even probably calculated mine to test lol i think i usually get about 240 when the low fuel light comes on don't know how much that translates too i usually end up putting back in at least 12 - 13 gallons.
Well 240 miles divided by 12 gallons would be 20mpg. Pretty darn good. 240 miles divided by 13 gallons is still 18.5 mpg (rounding). Still pretty darn good. I've never been over 18.5 or so, but I've also never been worse than 16. I'm pretty content with that.

I used to get crappy mpg when I first got my car (new-9500 miles). By crappy I mean 13-15 mpg or so. Since I've hit about 11000 miles or so, I've seen it go from 18 to 19 to 20 mpg and the last 2 tanks have had 21 mpg. This was mostly done on 89 octane gas and using 4k as a shift point with some high revs to pass people. I normally shift 1-3-4-6 and put into 6th at around 50 mph. When I have open road I drive anywhere from 75-85 mph but mostly 75-80 mph with some stop and go traffic. Not fun driving but it does help on gas. I also let the car warm up while sitting until the rpm's drop to 1250 or until 3 minute has passed. I also have a longish private drive (.6 of a mile) and drive in first gear down this road with no gas added. I also keep it under 3 rpm on the road until full operating temp. has been reached.

As a side comment my car dislikes 89 octane gas above 5k. Therefore I don't take it above that to minimize the chance of pinging or possible engine damge. When I want to have fun I put 93 octane in the tank (like right now).

I hope someone will benefit from my info and that's the reason I went into detail.

p.s. if my scanner will ever work ill post my gas sheet

But if you are going to drive around like that, then you might as well sell the 8 and get a Geo Metro or something. Sounds economical, but also sounds like 0 fun :(

Dennis

does a geo metro come with leather seats? ;) . I could redline my car like some but i need this thing to last for a while so i dont drive scary fast very much at all. As for 0 fun, like I said when I feel the need to drive it hard, I throw the 93 octane in and have fun like the last couple nights. In all honestly if i wanted a car that i drove hard constantly i probably wouldnt of chosen the 8, even though i love my car more than all but about 15 people on the earth.

Ok....my 'first' tank in my new '8' yielded 19.7 MPG!!!! But......I'm driving it pretty easy. At any rate, it looks/sounds like my MPG will be better than most?!

Forgot to add, I have a MT.

19.092 average mpg with 23,xxx miles on the car. Highest is 23.712 during a road trip and lowest is 7.200 at a track day at Road Atlanta. The car is a 6 spd Touring Package.

Standard Deviation is 2.36 mpg so I'm pretty much in control except during a track day or extended autocross. 245/40's on the car.

hahaha thats pretty funny i use 87 most of the time since the gas is really high around here but i redline the car a lot i now read people say their car is pinging or doing other crazy things with lower octane i'm a idiot someone describe what they mean.

I bought my new 6 speed a couple days ago. I travel 86 miles a day, round trip to work all freeway.

Are there any good tips out there for getting the best fuel mileage?

I read in one of the other threads that there are secondary fuel injectors that kick in at around 3700 rpm. Is that true?

I bought my new 6 speed a couple days ago. I travel 86 miles a day, round trip to work all freeway.

Are there any good tips out there for getting the best fuel mileage?

I read in one of the other threads that there are secondary fuel injectors that kick in at around 3700 rpm. Is that true?
Yeah, I think it's actually 3,750 rpm. But with your planned driving scenario, don't get too hung up on that. I'm getting just under 20 mpg with mixed driving, and I just did a 560-mile Interstate run at 75-80 mph and averaged 22 mpg. If you can keep it under 75 mph in 6th gear, you might gain a couple of mpg at best. Why not experiment with a couple of tankfuls, one with sustained speed over 75 mph and one at just under 75 mph to see if maintaining the revs below 3,750 rpm really makes a significant difference. My guess is that the gain is not worth worrying about keeping the revs below a certain point. We'd be interested in the results if you do such an experiment.

I just did a 225 mile highway trip running around 74mph the whole time and got 23mpg. This car isn't bad on a trip when you just let it cruise, you just get bad mileage around town because you have the opportunity to open it up some at stop lights.

just tried 93 again and i got 215 and i filled up 12.5 my car has had its fair share of problems too.

Well, im sure this has been assessed in a previous thread to which i briefly searched for and didnt find, but i have the 6 Speed MT and im getting about 20MPG average in town. What is everyone else pulling in and out of town? and state your transmission type. Just curious to see if my driving sucks or what. I usually shift at 3.5K to 4k RPMs. Thanks fellas/ladies. :D

Since a search of “gas mileage” returns 13 pages I can see why a new member would bypass all that info. Gas mileage has been discussed & discuss and discuss some more on this board. Bottom line is fuel economy sucks on this car, nothing you can do about it. 20 MPG is actually above normal and most members would love to get that. I too have a 6-speed and can get 20 if I shift like you. Problem is the 9,000-RPM redline entices you to drive hard and use more fuel. Count yourself lucky.

Yup, mileage has been discussed here many (ad infinitum) times before. they pop up in their own threads (like this), or can randomly breakout in any give thread.

but if you are getting 20mpg in town, you are definately getting more than most. it seems the board average is around 15-16mpg city, and i get in the 17s for city.

there's lots of things that can affect fuel economy...amount of weight in the car (driver, passenger, anything else), altitude, weather conditions, tire pressure, terrain, gas blends, traffic, etc...so its actually rather difficult to quantify.

I'm sure if i lived in florida, i'd get better mileage just because its flat, but i live in georgia, and its rather hilly here, the traffic is bad, and the lights aren't timed.

mechanically, the 2nd set of intake port opens at 3750rpm and the 3rd set opens at 6250 rpm, so the easiest way to keep mileage up is to keep it below 3750.

welcome to the board, and remember:
* don't rev over 3k until the engine is warmed up
* your gas mileage is going to suck
* shutting the engine off when its cold increases chances of flooding
* periodically get the revs above 8000 to clear out carbon build up
* the engine is designed to burn oil as it runs, so check your oil level regularly
* most importantly, have fun.

don't sweat the mileage too much (it is going to suck) because if you do, you won't be enjoying the car.

oh yeah, 6MT for me.

If you're getting 20mpg in town...then yeah, your driving sucks. ;) That's not how you drive a car w/a rotary engine!

But from an economical/fuel efficient stand point, you're the man. I get 17 - 18 mpg using that method.

I'm curious... what RPM are you usually going into second at from first while you're driving your RX-8 like an old lady and shifting that soon?

If you're getting 20mpg in town...then yeah, your driving sucks. ;) That's not how you drive a car w/a rotary engine!

But from an economical/fuel efficient stand point, you're the man. I get 17 - 18 mpg using that method.

I'm curious... what RPM are you usually going into second at from first while you're driving your RX-8 like an old lady and shifting that soon?


Well true, going from 1st to 2nd is definately no less than 4k. It would be way too soon.

Yup, mileage has been discussed here many (ad infinitum) times before. they pop up in their own threads (like this), or can randomly breakout in any give thread.

but if you are getting 20mpg in town, you are definately getting more than most. it seems the board average is around 15-16mpg city, and i get in the 17s for city.

there's lots of things that can affect fuel economy...amount of weight in the car (driver, passenger, anything else), altitude, weather conditions, tire pressure, terrain, gas blends, traffic, etc...so its actually rather difficult to quantify.

I'm sure if i lived in florida, i'd get better mileage just because its flat, but i live in georgia, and its rather hilly here, the traffic is bad, and the lights aren't timed.

mechanically, the 2nd set of intake port opens at 3750rpm and the 3rd set opens at 6250 rpm, so the easiest way to keep mileage up is to keep it below 3750.

welcome to the board, and remember:
* don't rev over 3k until the engine is warmed up
* your gas mileage is going to suck
* shutting the engine off when its cold increases chances of flooding
* periodically get the revs above 8000 to clear out carbon build up
* the engine is designed to burn oil as it runs, so check your oil level regularly
* most importantly, have fun.

don't sweat the mileage too much (it is going to suck) because if you do, you won't be enjoying the car.

oh yeah, 6MT for me.

Woohoo i have an excuse to ride it over 8000. And i didnt know that about the 2nd and 3rd intake ports. Thanks. And yea i figured it being a sports car would mean to not expect great gas mileage for sure, so i had an idea of what i was getting into.

Since a search of “gas mileage” returns 13 pages I can see why a new member would bypass all that info. Gas mileage has been discussed & discuss and discuss some more on this board. Bottom line is fuel economy sucks on this car, nothing you can do about it. 20 MPG is actually above normal and most members would love to get that. I too have a 6-speed and can get 20 if I shift like you. Problem is the 9,000-RPM redline entices you to drive hard and use more fuel. Count yourself lucky.

Yea my bad, i didnt see the search because i am frantically trying to hide this window at work so the boss doesnt see HA. I just searched the first two pages of this particular section. Wont happen again :D Speaking of 9000, my 8 tends to get real shakey around 9k, yours?

Speaking of 9000, my 8 tends to get real shakey around 9k, yours?
I only hit 9,000 on the track and mine is fine. No real need to go that far over 8,500 power wise.

welcome and congrats
do a search please

What I haven't been able to find is an easily understood explanation of why the mileage sucks.

Please understand, I know it does. I'm not saying anything about that. I'm just curious as to what the technical reason is. With about 90% fewer moving parts, you'd think the thing would be better.

Is is simply down to the fact that the apex seals are not able to keep as tight a seal as a piston ring? Is that where the efficiency losses are?

Thanks

Hunter

I hate you guys...I stopped tracking my MPG but I was never even close to 20 in the city. I think I got 18 once on the highway.

the efficiency losses in the old 13b was partially due to valve timing and partially due to the long combustion chamber.

on the old 13b, the intake and exhaust ports were on the rotor housing, and by having them there the apex seal was the divider that kept intake and exhaust seperate...but it wasn't 100% effective (but what is?) and some unburned fuel would slip out through the exhaust.

this was addressed on the renesis by moving the ports to the side housing. by doing this the intake/exhaust "divider" became the side seal, which is better able to keep the two seperated and reduce, if not elimite unburned fuel slipping through.

next is the shape of the combustion chamber. it is fairly long, and at high rpms it become difficult for the fuel to have enough time to burn before getting exhausted.

i think that's a pretty good layman's explaination *nods to self*
but someone like rotarygod could explain in more detail (and possibly some areas that i missed).

What I haven't been able to find is an easily understood explanation of why the mileage sucks.

Please understand, I know it does. I'm not saying anything about that. I'm just curious as to what the technical reason is. With about 90% fewer moving parts, you'd think the thing would be better.

Is is simply down to the fact that the apex seals are not able to keep as tight a seal as a piston ring? Is that where the efficiency losses are?

Thanks

Hunter

As I understand it, it's not the sealing ability of the apex seals, it's the lousy thermal efficiency of the wankel design (and there's no way around it that anyone's found yet.)

It's lousy because of the large area the comustion charge has to do work over. All that wasted energy gets put out as heat, into the metal, into the water, into the oil..

If you think 16mpg is craptacular from a 1.3 liter 200-ish HP na wankel, what would you had thought of a 16mpg 1.3 liter 140 hp na wankel?

That was the NA 13B.. and 16 mpg was avg in the city for that motor..

Or how 'bout the 12A? 100-ish hp, and yup... same dismal gas mileage.

IIRC, the single-rotor, 80hp (I think?) NSU Ro-80 also got about the same..

All considered, I think 16 from the current 200+ motor is quite remarkable.

By the by, isn't 16~20 about right for most any 200+ horse motor? ;) (variable displacement tricks like those in the modern hemi need not apply.)

The wankels are a *little* worse than a piston motor on gas, but face it.. if you're gonna make 200 hp, you're gonna move enough air, and have enough fuel, to supply that demand.. and that means, Power Costs.. How Much Do You Want?

All considered, I'll forsake the mileage, and enjoy the smmmmmooooth, progressive, controllable power of a rotary over most pistons.

The *only* thing that compares to these rotaries, imo, is a v-12... and that I can't afford, not anytime soon.. :D

i shall sum up all my thoughts about this right now....read his post ^^ :D

I hate you guys...I stopped tracking my MPG but I was never even close to 20 in the city. I think I got 18 once on the highway.


i stoped trackgin it long ago as well......when i started to average like 14-15 in the city ..adn 17 on highway....lol ohwell what can i say my baby likes to rev :D

Okay, thanks
the large combustion area helps explain things to me

Hunter

Whe does everyone get so upset when someone post a topic that has already been talked about. I believe that all there is to discuss about the car has most likely been brought up before so then why continue with the forum. The point I am trying to make is that there are always new members and people with new information and opinions. I still find it interesting to read about topics already discussed because there is usually fresh ideas and opinions.

It's amazing how the same people say "This has been commented on a thousand times" still find the need to comment. ...boggle... Oh wait, I just did the same thing...lol!

All my RX-7s averaged 20 MPG and my 8 is averaging between 19-20 MPG with mostly city driving. Haven't had a highway trip to check mileage yet. Pretty happy with those numbers.

I'm going to add some information that I didn't find in this gigantic thread.

If you are driving...

16 mph or less in 1st gear...
27 mph or less in 2nd gear...
37 mph or less in 3rd gear...
52 mph or less in 4th gear...
62 mph or less in 5th gear...
73 mph or less in 6th gear...

...then you're getting optimal mileage in that gear. If you go 1 mph higher than the numbers I listed, you'll be at exactly 3750 RPM, meaning the port will open, and your car will be using more fuel.

So if you shift at or before those speeds in those gears, you'll get the best mileage possible in your particular RX-8. I'm still figuring out the ranges in mph of the dead zones (power wise) for each gear...because unfortunately they DO exist in the manual as well just like they existed in my old automatic.

I guess I now understand why I thought it was (is this phrase right?) "coming on the cam?"

Yes, I know there's no cam shaft in this thing. But, it seemed as the revs went up there was more power. I must have been feeling the second (and eventually) the third injector coming on line.

Is that about right?

Hunter

no you were feeling the secondary and tertiary intake ports opening

oh
sorry :o
you're right

ports, not injectors

I'm going to add some information that I didn't find in this gigantic thread.

If you are driving...

16 mph or less in 1st gear...
27 mph or less in 2nd gear...
37 mph or less in 3rd gear...
52 mph or less in 4th gear...
62 mph or less in 5th gear...
73 mph or less in 6th gear...

...then you're getting optimal mileage in that gear. If you go 1 mph higher than the numbers I listed, you'll be at exactly 3750 RPM, meaning the port will open, and your car will be using more fuel.

So if you shift at or before those speeds in those gears, you'll get the best mileage possible in your particular RX-8. I'm still figuring out the ranges in mph of the dead zones (power wise) for each gear...because unfortunately they DO exist in the manual as well just like they existed in my old automatic.

I dont think 16 MPH = 3750, ill check later. But yea i have been driving in this manner since day 1. and im getting 20 MPG average.

Ok 16 MPH is 3750, sorry to doubt you. Well i went to the grand canyon this weekend with the 8. Which was roughly 350 miles there and 350 back. I averaged 25 MPG. So shifting at 3.5K RPM in town gets me 20 MPG, and keeping the RPMs below 3750 in 6th gear got me 25 highway.


Pic of me and my girl at the Grand Canyon :D

http://www.tightashell.com/users/TheTightest/6e80.jpg

^^good work on the girl :)

Better yet, get a drafting buddy! I drafted my wife's car(Pontiac GP) at 66mph from Virginia to Flordia and averaged 27mpg per tank! Best I've ever seen, with 16k on the odometer and a Rx8store exhaust. My previous best was 26mpg from Michigan to VA. Sure I got passed by everything, but with 400lbs of all my possesions in the trunk and backseats, I think I fared pretty well.
d

I've had my high power 8 for a fortnight and am getting just under 19mpg after 600 miles 50:50 urban/inter-urban, which at over $7 per gallon and rising is a big ouch. I think the UK car is supposed to return better mileage than the US one but not much evidence of this. Its testament to how good this car is that its selling so well in a country with insanely high fuel prices. Most drivers here are reporting 21-23mpg over the long term. Incidentally we only get the choice of 2 manual versions in UK one with 187hp and a 5 speed box and one with 228 hp and a 6 speed box plus more standard kit. The lower powered one has a bit more torque but only revs to 7,500 - seems to defeat the object of a rotary engine. That engine seems to return the advertised 26 mpg.

With my "M-Flash" I averaged 150 miles per tank....
I had the "P-Flash" upgrade (I use this term loosely...) two weeks ago.
My last three tankfuls gave me 120 (+/- 5) miles each...

Did I read somewhere that part of the "P-Flash" update was to include exchanging my current plugs with hotter or colder plugs?

I have an appointment this week for a "Re-Flash" or perhaps they'll give me the latest and greatest "R-Flash".

I like this car, I just wish it didn't suck so much fuel.
Heck! My 67 Vette with a 327 got better MPG then my 8!
Figure that one out!

i went to san diego last week on a full tank and i got 275 miles there on a round trip... averange speed was 75mph to 95mph i notice on the high way you get good gas mileage for the 8. and on the streets you will get about 222miles on a full tank. i drive a manual 12 1/2 gallon tank cant complain gas is high so put 91 octane gas and oil in you car for good results..

I'd love to see someone try and keep their speed down to 55~65 MPH on a highway trip. Bet we'd get fantastic mileage.

I did a R/T Albuquerque-Phoenix last weekend and averaged just over 20 mpg. I had maybe 200 + extra pounds in the trunk and pretty much lead-footed thru the mountains..which is soooooo enjoyable with this car. Coming down the Mogollon Rim, Show-Low to Peyson, I encountered alot of traffic which significantly lowered my normal speed, but GREATLY increased my mileage to what I could only estimate to be nearly 30 mpg. So, yes, the 8 is quite capable of getting very decent mileage at "normal" speeds; but I don't think "nomal" describes most of us!

Best - 21.68 MPG = 10.85 L/100 KM - Range 258KM in 28L
Worst - 7.88 MPG = 29.86 L/100 KM - Range 177KM in 52.91L - DAMN BEEPS! :D
Average 16.33 MPG = 14.40 L/100 KM - over 28,289 KM
"N" flash
All taken with actual distance, and actual volume.
Not this 1/2 tank, 1/4 tank stuff.
The 8 is easy to fill up within I'd say 1L every time so error will be around 2% max.
Rule - Best mileage is when the car is in the shop and you can't drive it.

I'd say keep below 3750 in 6th on the HWY and draft as much as possible behind as big a truck as possible. Sure you will get stone chips - but think of the couple dollars you will be saving.

Want fuel economy? Get a TDI.

I also have a 91 AWD talon that when on full boost > 300 HP. Off boost it is most likely under 130 HP. This thing gets around 11.2L/100km average. Even with the added drag of the AWD - and about 100lbs heavier.

Rotaries ain't efficient. Put a 4-banger in the 8 - say from an S2000 with similar HP ratings and see what it'll get.

Support the WAR.. Buy more friggin GAS!

Major losses in a car - drivetrain losses, accelerating upto speed, and wind drag.
It is possible that the 170HP at the wheels we are measuring when crank is supposed to be 238HP has something to do with huge drivetrain losses and hence - poor economy. Merely speculation.

I just wish I didn't have to waste so much time at the pumps! :p

Hmm I was one of those first buyers at VIN 1211 and watched my mileage like a hawk for the first 3 months and have kept fill-up records since July 2003. My RX8 in town driving 30-50 mph start and stop driving would get 18mpg with no AC and shifting below 3700 rpm. I then drove normally with AC and without AC and got a 16mpg average on the same driving conditions. My car is a daily driver BTW. Now, recently my figures are showing that I am getting 14 MPG on the same run driving normally. The end of May the dealer replaced 4 spark plugs and checked everything over per se. I am not sure what to think.

According to the UK owners club trials you can get 55mpg at a constant 30mph in 6th and about 37mpg at 50 mph in 3rd or 4th. Aternatively if you do 80 in 3rd you will get 14 mpg. Source 'The spin' Vol 2. I suspect however that monitoring your mileage is not a route to true happiness as an RX8 owner.

Just got back from a 1276 mile road trip.

Consistently filled up at 1/8th of a tank left and was getting between 282 & 287 miles.

Actual mileage was between 21.5 and 22.11 for all the tanks, except the last one where the needle was on E and I went 327.7 miles. That last tank I got 25.20 mpg where I drafted behind a semi most of the way.

The whole trip was with AC on Recirc, and about 70% cruise control at 72mph. For portions of Tenn where the speed limit is 70mph, I still got 22mpg cruising at 85 with the rest of the traffic.

Based on this:

16 mph or less in 1st gear...
27 mph or less in 2nd gear...
37 mph or less in 3rd gear...
52 mph or less in 4th gear...
62 mph or less in 5th gear...
73 mph or less in 6th gear...

Would driving on 6th gear in the city save more gas, since the RPM will be lower than if you were on 4th and cruising at 35-40 mph? Just curious...

I'm still "breaking-in" my car, but am getting 20 mph, shifting @3500-3750 RPM. Using Shell 91 Octane. Plan on using 87 to see if I get better/worse miles. So far, am happy with this.

OH! My car will be in the group 2 recall. What flash does that involve, and..do I need it? I hate for them to flash my car when I'm getting excellent mileage! Can I refuse the flash? Anybody know?

depends on the terrain. if the city is flat, and you need just enough power to maintain your speed, 6th gear should increase your gas mileage, but if there are hills, and you'd have to floor it to get up the hill and stay in 6th, you're better off dropping to a lower gear and be higher in the rpm band, but using less throttle.

and for group 2, i believe that would make your car a 2005, right? so you'd be getting the E flash for 6mt. from what i know of it, its basically the same as the R flash for the 04 6mt.

it changes the way the ecu behaves in certain circumstances, in efforts to keep the exhaust temperature down while the car is not moving, to keep the heat from damaging undercarriage parts. it also incorporates all the previous updates, such as a/c cutoff rpm, etc.

and since its a recall, i don't know if you can refuse it or not.

::edit:: depending on your state, you might might not be allowed to get an emission test done and you could also possibly exclude yourself from further recalls.

Don't know if anyone mentioned this link yet:

http://www.fueleconomy.gov/mpg/MPG.do

Maybe we all should participate in this research, input the MPG of our car......

New RX-8 owner here (2004 6-speed). Through my first 4-5 tanks with the car...currently at 29,500 miles...I've been averaging 21mpg. After all the horror stories I had heard, I'd prepared for much worse...so I'm more than happy with that.

I havent been calculating my MPG, but I do look at how much miles I get before fill.

I usually get about 200 miles before the light comes on, and I go to about 220 before I fill.

I dont know how this compares to MPG? So how is everyone doing with miles per tank?