I just checked my MPG with my new engine and the most current flash (S?)

This was ALL city driving. No highway

6 speed MT

14.25 MPG

Pretty dang low.


:(

Rob in Vegas

I get about 180 - 200 on a full tank but with the Greddy turbo kit! I try to stay off boost, but I just can't help myself when a stang/evo/ or sti get next to me :D

Just wanted to say "hi". I'm new to this group; have a 6-spd. which I bought approx. 1 year ago. I, too, have been very disappointed with the MPG. For the first 8 months I owned it, I only drove very short distances "in city"; less than 3 miles much of the time. I got somewhere between 11.8-14 MPG. Now driving about 10 miles to work each way and consistently get 14.5-16 MPG. Only did a long trip (~500 miles each way) once - got 20-21 MPG. Took my car in today for the fuel tank recall and asked to have the car re-flashed. (Thanks for all the threads on that!) Dealer said it would MAYBE add 0.2-0.4 MPG and not to get my hopes up. I hope he's wrong!

(I'm spoiled - my Ducati gets 50+ MPG and it's quicker, too!!!)

Lily

i just put in a lil over half a tank. so lets say i had about 8 gallons. I drove the car 7 miles to school every morning in city traffic and out of school i would take the highway home. Keep in mind i redlined the car at least a dozen times and some of those redlines were thru 3rd gear :). i got a total of 150 miles on that lil over half a tank. thats about 18.75 mpg with a lot of redlining! I just recieved the updated flashes and recall work and my mpg has no doubt benifited, cus before this i was gettin about 15 mpg.

o yea, i also have 13500 miles on the car.

First MPG check done while around town. 98% city/2% HWY spirited driving, full tank.

13.399 MPG. Watching the needle sink was scary.

Now I'm going to see if I can get under 10! :D

Just took my car in for the fuel tank insulation recall. Had it reflashed while I was there ("R" flash). I didn't think it was possible, but based on only one tank, it made it WORSE! I got 178 miles on a tank! Filled up with 13.5 gals - that's 13.2 MPG. Granted, it was all city driving, but YIKES - that sucks!

Lily

OK, I stopped using my 8 to commute from work/home, since the MPG of the 8 and the gas price are terrible.
I used to have 14~15MPG before, about 10 miles from home to work and 20 traffic lights in between, stop and go....
I have almost 17MPG now, driving mostly in weekend, mixing highway and city, shifting gears at 3k~4k, driving like a grand mom.
Now, how the hack can I get to the EPA index(24/18?!) Push my car wth the engine off to get the extra mileages?! I mean, I am driving highway/city and driving like a Tercel already?! And I still can't reach 18MPG? I know, some ppl would say "Don't complain about the MPG while you are driving are sport car.....blah blah blah...".
If the EPA showed 19/14MPG before I bought the 8, and I still choose to buy this car, I have no complain. However....... I'm complaing about the misleading EPA index.

New record for me... 22.4 MPG! I have no idea why it jumped over 2.5 MPG..

I was getting 19 mpg all day and 22 highway but now after my car flooded i can't break 17 i am getting about 15.7 on mixed driving.

OK, I stopped using my 8 to commute from work/home, since the MPG of the 8 and the gas price are terrible.
I used to have 14~15MPG before, about 10 miles from home to work and 20 traffic lights in between, stop and go....
I have almost 17MPG now, driving mostly in weekend, mixing highway and city, shifting gears at 3k~4k, driving like a grand mom.
Now, how the hack can I get to the EPA index(24/18?!) Push my car wth the engine off to get the extra mileages?! I mean, I am driving highway/city and driving like a Tercel already?! And I still can't reach 18MPG? I know, some ppl would say "Don't complain about the MPG while you are driving are sport car.....blah blah blah...".
If the EPA showed 19/14MPG before I bought the 8, and I still choose to buy this car, I have no complain. However....... I'm complaing about the misleading EPA index.

Thanks for your post - it sounds like you do the same drive to work (or did) as I do; 10 miles each way with way too many lights on the way (probably about 10 or so for me). If I drive like Grandma, I get 13-15 mpg. Last tank, I just said "to heck with it" and drove like I want to. I got 12 MPG!!!!!! I agree - I wouldn't be bitching except that I was stupid enough to actually believe that 18/24 EPA rating on the new car sticker when I bought the 8. True- they're usually misleading, but not by this much, in my experience. I do like my 8, but know I won't own it long because of this. Too bad it's so wet in Seattle. I'd take my motorcycle to work everyday if it wasn't so dark, cold and wet - too DANGEROUS for this biker chick!

Lily

I was getting 19 mpg all day and 22 highway but now after my car flooded i can't break 17 i am getting about 15.7 on mixed driving.

Clearing the flood condition can fry your cat if it is done wrong. The mileage change could be due to a melted converter.

Thanks for your post - it sounds like you do the same drive to work (or did) as I do; 10 miles each way with way too many lights on the way (probably about 10 or so for me). If I drive like Grandma, I get 13-15 mpg. Last tank, I just said "to heck with it" and drove like I want to. I got 12 MPG!!!!!! I agree - I wouldn't be bitching except that I was stupid enough to actually believe that 18/24 EPA rating on the new car sticker when I bought the 8. True- they're usually misleading, but not by this much, in my experience. I do like my 8, but know I won't own it long because of this. Too bad it's so wet in Seattle. I'd take my motorcycle to work everyday if it wasn't so dark, cold and wet - too DANGEROUS for this biker chick!

Lily

my low tank is 16.5, average is 18.5, and high is 23.4. last tank had a bit more spirited driving than normal and i still managed 17.8. also just go flashed to the R revision, so i'm interested to see what effects that has, if any.

I seem to be getting worse mileage with the "R" flash. Anyone else seeing this?
I just tried a new oil additive that works wonders in piston engines, but if it's doing anything in the rotary, with mileage, it may be the problem, not a solution. I must say, the stuff does make it run like a well oiled clock, so maybe the added fun is adding to the reduced mileage. Even though I feel as if I'm driving the same, I know that speedometer is saying something different.
I almost get the feeling that the later flashes that have added to the low-end torque may be doing this by more agressive throttle application in the drive by wire system. I don't know how the system works, so this may or may not be possible with a new flash. I just know the thing really jumps out from a stop with very little driver throttle input.
I really don't know why I'm so obsessed with mileage, I can afford the gas and this thing is such a pleasure to drive.
By the way - via edit - I was averaging right at 20 mpg in mostly two lane road, semi-country (building up way too damned fast) commuting, now I have dropped to a hair under 19 mpg.

I just filled up for the first time in my new 2005 MT 8 today. I'm hoping the 13.8 MPG improves with time! I've been driving 80/20 city/highway miles and TRYING to be good about keeping the engine under 4k rpm during the break-in period. I'll try keeping it under 3750 rpm and see if that improves things.

Hi, first post here. I've got about 1000 miles on my new 2005 MT, and I'm getting over 18MPG. I started checking on the second tank, and even after a day of fun driving through the mountains, I still got a little over 18. Overall, with weekday commuting and weekend fun, I get around 22-ish. Try driving at a higher RPM... 3000 RPM is almost lugging the engine. I almost never drive under 4500 RPM... shift at 6 - 8000 RPM... :)

This is my report on my 2005 6sp.

NYC
30-40 deg.
93 oct.
Normal Driving. 3-4k Shifting
80% highway 20% local.

Milage------Gallons MPG
427---------3.9
481--------13.3------13.8
665--------12.5------13.8
858--------12.9------15.4
1067-------13.2------16.2
1223-------11.4------11.8
1425-------13--------17.7
1642-------14--------16.6
1843-------12.4------14.27
2066-------13.27-----17.98


I am going to use the tripometer and start documenting it too.

Overall, I seem to be gaining a bit. I also have a feeling that driving at higher speed saves gas? :spank: (around 70-80 mph) instead of my usual 40-60 due to traffic every day.

I don't understand your table. For example, at 427 miles you filed up the tank and it took 3.8 gals. Then 54 miles later you filled the tank with 13.3 gals. That certainly is very poor mileage :) , so I suspect you transposed some numbers. You should expect to get about 19-20 mpg with that type of driving based on what other owners have reported here on the forum.

I don't understand your table. For example, at 427 miles you filed up the tank and it took 3.8 gals. Then 54 miles later you filled the tank with 13.3 gals. That certainly is very poor mileage :) , so I suspect you transposed some numbers. You should expect to get about 19-20 mpg with that type of driving based on what other owners have reported here on the forum.

I only had few bucks in my wallet at that time. 3.8 gal gave me approximately 54 miles. Divide that by 3.8 gave me 14.2.

I hope the formula is correct.
Nedor

Ours AT 05 8 is getting better mileage as we get more miles on it. First tank we measured was 18.32 and now with a little or 2500 miles on it, we got 22.8 and that's with an extended drive up a mountain in 3rd gear mainly. I'll get off my "my mileage sucks" kick now :)

Tim

13,000 now on my 6MT. Done quite a few road trips on I-70. So I generally run at about 80mph on the highway. It's getting a consistent 21-22 on the plains (this is complete tanks of fill up, merge, and run till the next gas station.) In the mountains I can get around 24-25. As far as city, I was getting about 20-21 in mixed driving, but since the R-flash it seems to be more like 17. I need to keep an eye on that.

OK, I've had my 8 for about two months now. On the last 10 tanks of gas I am averaging 11 MPG in mixed driving. On a few tanks I drove like Grannie May taking her Sunday drive to the grocery store and still only got 11.5 MPG. And, I live in Vegas, so it has been nice weather - usually 50 or 60 degrees ambient temps.

Here are the details of my 8:

MT
22K Miles
no mods
BF Goodrich KDW Tires - 35 PSI
91 Octane Chevron

I think I have the latest flash as I have a service receipt from 10/05 that shows an ECU download was installed.

I know this is a sports car, but 11 MPG is just unreasonable. That's $100 a month extra for gas than I budgeted.

Any ideas? I love the 8, but a 36 foot motor home would get better gas mileage.

Could my cat be damaged? Problematic plugs? Extreme carbon deposits in the engine?

I would like some ideas before I go to the dealer and get snubbed... TIA.

I have a sudgestion, im very aware the the rotar is a very unique motor, but what im about to say applys to any fuel consuming applacation. weather you have a large V8that revs low or an Rx8 that revs high, not reving the motor the way it needs to be reved or likes to be reved, Can and does cause carbin build up in the fireing chamber. As i saw on page 1, you dont rev you engin, probley think your saving it, infact every so often, you need to Run it out, make it work. This may help your cace.

Well more so for cars with more miles with mileage decressing

Ok, im seeing a new topic arise. Witch is the best flash for the update?

Greetings!

This is my first post on the boards, but I have been searching/reading/lurking for a pretty long time now. I've been learning all I can about 8's because I am looking forward to replacing my 5th gen Prelude and S/C'd '01 S2000 with one car that covers 95% of what I like about both cars and none of the attributes that I don't. I'm not a complete newb to the "wankel lifestyle" ;) ... but there's always more to know.

That being said. Niether of my Hondas post particularly better mileage numbers than the 8 does, even before I modified anything. I average around 18 mpg in each in mixed use. I have never gotten better than 230 miles to a tank in the Lude and that's my commuter car! There have been plenty of times where I have managed far less than that, but had fun doing it. I guess I don't understand what some of the pump shock is all about.

The same thing goes with checking your oil while topping off your tank ever other gassing. VTEC engines love burning up oil in the higher rpm range. The lude will go through a quart every 3000 miles or so... To me alot of the "quirks" that some feel are annoying in the 8 are just...well...normal

Now to my question. I'm assuming that if I buy new that I don't have to worry about what flash I'm on...it should be M or N as I understand it...however...if I buy a used one, should I have the flash checked by the dealer before I buy it? The deals currrently for new ones are pretty good. I just want to know if it's worht the time to save a moderate amount of money.

Love the site and I can't thank you guys enough for everything I know now before I buy.
Ride on! (and sorry for the book),
Led

Great first post! I tend to agree with your comments about obsessing about the "shortcomings" of the RX-8. Mine will be 2 years old soon and I haven't experienced any of that and have averaged 20+ mpg for 10K miles, mixed driving with regular runs to the redline.

An '05 or '06 RX-8 will almost certainly will be up to date. In any case, don't worry about the ECU level since you could take the car to any dealer and have it checked/updated free of charge. The software level depends on which model and which country and/or region of the country the car is operated in. You can see what I mean by going to the Service Bulletins and reading the one concerning a No-start condition. There is a table in that SB that lists the software levels by year-model-region. As an example, for an '04 MT in the US (except for Cali) I think the level has an "R" at the end of the version number and it's, therefore, referred to as the, duh, "R" flash.

Thanks for the heads-up Go48! I haven't gotten through all the TSB reports yet, but I'm certainly trying. It's a lot easier learning about them here than when I had to go through the same deal with the S2000.... The reports for the first two model years of that car look like something a NASA computer might spit out... No joke!

Looking forward to my first brand new car!

Thanks for the heads-up Go48! I haven't gotten through all the TSB reports yet, but I'm certainly trying. It's a lot easier learning about them here than when I had to go through the same deal with the S2000.... The reports for the first two model years of that car look like something a NASA computer might spit out... No joke!

Looking forward to my first brand new car!
You're certainly welcome. And when you do get the car, you might consider joining us at the Mazda Sportscar Club of Washington (www.mscw.com or maybe it's org). It's a great club with a variety of activities ranging from autocross to scenic tours to shows.

Wow...checked out MSCW... I'll definitely join! Your next couple of meets are at Tysons....five minutes from my front door! :)

Wow...checked out MSCW... I'll definitely join! Your next couple of meets are at Tysons....five minutes from my front door! :)
Yeah, that's why I suggested that you check them out. Unfortunately, I'm nearly 2 hours away from Tysons so I don't attend the meetings.

I have a new 05 (8/05 build date) with about 400 miles on it. With 90% city driving I get about 12.5 mpg. Very poor, was expecting 15 to 17mpg. I have been doing a lot of reading and feel the most likely cause of some RX-8s that rate so poor could be as follows.

1) Thermostat: could cause trouble but I think it would be rare.
2) Catalytic converter clogged: Maybe but I would expect poor performance to go with it.
3) Engine Compression: Easy check and performance would suffer
4) Bad MAFs: This I feel holds real promise, I understand that the MAFs in the RX-8 can have a wide difference in voltage from car to car. If the air density is miss reported so would the gas delivery…true?

Has any one here with bad mpg ever switched their MAF with a RX-8 with good mileage to see the effect on both cars?

ive seen 2 bad tstats and only one bad MAF. lots of dirty MAFs tho.. the voltage difference is highly overstated and not something to even bother about. we're talking a difference of .01v between some (not many) cars(less than a oily dirty MAF) which could be a result of inaccurate rpm readings. that will not translate into a huge mpg disparity.

what will is 1 car staying in open loop while others are in closed loop. this makes the car look at a table for its AFR and will keep the AFR in the 12s or 13s instead of hunting for 14.7 like it does in closed loop.

compression dropping may not be felt at all. might show in a dyno if you dyno often. but it could cause mpg losses well before its felt in performance.

ive seen 2 bad tstats and only one bad MAF. lots of dirty MAFs tho.. the voltage difference is highly overstated and not something to even bother about. we're talking a difference of .01v between some (not many) cars(less than a oily dirty MAF) which could be a result of inaccurate rpm readings. that will not translate into a huge mpg disparity.

what will is 1 car staying in open loop while others are in closed loop. this makes the car look at a table for its AFR and will keep the AFR in the 12s or 13s instead of hunting for 14.7 like it does in closed loop.


What is the tstats?

I thought open and close loop transition was at a preset event (rmp/ throttle setting etc...) would not all cars transition the same. If not what controls the transition?

Also how dose the car determine what the accrual real time AFR is, I believe the 02 sensors tell the computer this. If this is the case could there be discrepancies between 02 sensors misreporting the AFR?

Raptor,
How much time is spent sitting at lights/traffic. To improve your milage, take a long trek by freeway or better yet, back roads. I get 17-18 mpg in the city but its not a lot of sitting in traffic. What shocked me was country road mountain driving I got over 20mpg and never let the tach fall below 4K. Idling just sucks gas on this engine.

Mike

Thermostat. when you start the engine the car stay in Open Loop until it is warmed up. It then switches to Closed Loop until the Load/RPM transition that is programmed into the PCM. If you have a bad T(hermo)stat then the PCM never goes into Closed Loop.

If there was an issue with your O2 sensor your PCM would tell you by lighting a CEL. It compares BOTH O2 sensors against other information to determine if they are working correctly.

My city driving is suburban city driving. Drive for 2 to 5 blocks sit at a light for about 7 miles to work then back home another 7 miles. Chicago weather 32 lately. I’ll be doing a long Highway drive soon.

Zoom44,
What would be signs of a stuck t-stat? My car takes about 7 minutes to warm up but the inside of the car take over 15 minutes to start getting warm air. Is this normal? My temp gauge reads a notch below half way once warmed up.

What is your gut feeling as to the large discrepancy between cars?

I have a new 05 (8/05 build date) with about 400 miles on it. With 90% city driving I get about 12.5 mpg. Very poor, was expecting 15 to 17mpg. I have been doing a lot of reading and feel the most likely cause of some RX-8s that rate so poor could be as follows.

1) Thermostat: could cause trouble but I think it would be rare.
2) Catalytic converter clogged: Maybe but I would expect poor performance to go with it.
3) Engine Compression: Easy check and performance would suffer
4) Bad MAFs: This I feel holds real promise, I understand that the MAFs in the RX-8 can have a wide difference in voltage from car to car. If the air density is miss reported so would the gas delivery…true?

Has any one here with bad mpg ever switched their MAF with a RX-8 with good mileage to see the effect on both cars?

Are you warming up the car in the mornings?

Are you warming up the car in the mornings?

This I have noticed has been killing mine lately.

I can almost watch the needle go down as I sit there and shiver.

Exactly, if it's "only" around 30 degrees F, don't bother warming up. Start it for 15 seconds and go, but go real light on the throttle until the car warms up in about 5 minutes.

Raptor, you said you were doing mostly city driving. That tells me you are doing many, many startups over a single tank (as opposed to doing one or a couple of startups for a long distance trip at least 300 miles). As I mentioned before, the more startups you do, the lower your mpg. This is a factor that no one else has really mentioned. In fact, mpg falls quickly over many startups, even if you don't warm up the car. Now imagine what it would do to someone who is warming his car during all those startups! Even 10 to 15 startups will bring you down real good. I bet you are doing at least twice as many for city driving over one tank of gas.

Are you warming up the car in the mornings?

Only about a minute then driving below 4k till warmed up. Engine warms up in about 6-7 min.

Raptor, you said you were doing mostly city driving. That tells me you are doing many, many startups over a single tank (as opposed to doing one or a couple of startups for a long distance trip at least 300 miles). As I mentioned before, the more startups you do, the lower your mpg. This is a factor that no one else has really mentioned. In fact, mpg falls quickly over many startups, even if you don't warm up the car. Now imagine what it would do to someone who is warming his car during all those startups! Even 10 to 15 startups will bring you down real good. I bet you are doing at least twice as many for city driving over one tank of gas.

I think you are right cooder but based on what I'm reading there are other who do similar driving and are getting much better mileage. I'm looking into setting up a mpg tracking web site that will go into far more detail on driving habits, temp, distances then is possible with the simple pole method here. I hope to get a clearer picture of the RX-8 gas consumption.

Zoom44,
What would be signs of a stuck t-stat?
What is your gut feeling as to the large discrepancy between cars?

ONE IS BAD GAS MILEAGE:D:

My gut feeling is the disparity is caused by 3 things-

1. amount of short trips. those trips around the block for lunch KILL mpg
2. short mileage/long time daily trips. going 7miles sounds short but if it takes 30 minuted thats alot of time not going anywhere. car gulps gas at idle
3. not shifting. people spend alot of time in 2nd and 3rd gear whenthey should be in 5th and 6th. you can be in 6th at 42mph. for fuel efficiencey you should be. thats why the shift points suggested in the owners manual are the way they are.

then there are the people who actually have a problem my gut on these is

1.bad Tstat
2.bad plugs
3. bad cat

warming and not moving for more than a minute is a waste of time and fuel

I'm looking into setting up a mpg tracking web site that will go into far more detail on driving habits, temp, distances then is possible with the simple pole method here. I hope to get a clearer picture of the RX-8 gas consumption.

data gathering http://www.rx8club.com/showthread.php?t=13280&highlight=statistical


results

http://www.rx8club.com/showthread.php?t=13404&highlight=statistical

data gathering http://www.rx8club.com/showthread.php?t=13280&highlight=statistical


results

http://www.rx8club.com/showthread.php?t=13404&highlight=statistical

This is just what I was looking for, There should be an area on this board that holds all this related info. A lot of what I was looking for I find exists but it is not always easily found on searches.

Thanks agian, you've been very helpful.

mazda techs are driving my car around right now because i complained about poor gas mileage (13mpg) to see for themselves. =/

Not sure if anything could possibly done but, I've gotten those figures with fairly conservative driving all year round. =/

I am averaging a little less than 10 mpg, I have less than 600 miles on my car and I am shifting before 3,750 rpms to try to conserve fuel. I hope the mileage gets better, I was hoping to get between 17-20 mpgs. I was getting that on my wrx that I traded in.

Yeah I hear you guys. I'm at 2300 miles, and the best I've averaged has been 14 mpg. I have driven conservatively for a couple tanks, and have gotten no more than 200 miles before the empty light. I haven't done my inaugeral oil and tranny/diff fluid change yet, so perhaps that will help a little. I dunno, I keep hoping the saying about rotarys getting better as they age is true, but right now I'm filling up every couple days. Ouch.

Is there any kind of formal complaint customers can make to Mazda for their 18/24 estimates? I've spent two entire tanks on a 400 mile trip, with cruise control on, no a/c. I would say those estimates are a tad bogus.

so my gas light came on after 200 miles of driving, I go fill it up and only managed to put in 12.8 gallons to fill it up... is the car that paranoid of the fuel tank despite having 3.1 gallons left? i should theoretically get 40-60 more miles of driving. would be nice to break 200 with all city driving without having the fear of running out of fuel so soon.

my empty light went on at 195 then I could only get 13.25 gallons in, I guess there was about 2.65 gallons left. Anyway I tried 89 octane this fillup and I am at 122.5 at my half tank line. I am usually at 100 miles with premium, plus my tailpipes are not black. I did not really notice a change in performance when I got on it.

Ok,

I just filled up my tank this morning, and I got 114.5 miles on the last tank! If this is a 14 gallon tank, then I am getting 8.1 MPG! This is the lowest that I have seen on any thread? What should I do? Also, does downshifting or "engine braking" burn gas in a rotary? I can't see what I am doing wrong. The car has 32000 on it, and they are all city miles. I drive it moderately hard, but nothing crazy?! Whats up mazda? I love the car, but my Ram 3200 gets better mileage!

It's actually a 15.9 gallon tank. So, by your math, you're only getting 7.2 mpg.

Ok,

I just filled up my tank this morning, and I got 114.5 miles on the last tank! If this is a 14 gallon tank, then I am getting 8.1 MPG! This is the lowest that I have seen on any thread? What should I do? Also, does downshifting or "engine braking" burn gas in a rotary? I can't see what I am doing wrong. The car has 32000 on it, and they are all city miles. I drive it moderately hard, but nothing crazy?! Whats up mazda? I love the car, but my Ram 3200 gets better mileage!
First of all the car does NOT have a 14 gallon tank. Read the manual. Second, to get an accurate number for miles-per-gallon (MPG), you need to divide the miles driven by the exact number of gallons you added to the tank. I doubt if you are only getting 8 MPG. So, note the mileage on your odometer next time you fill up. Drive however many miles til your low-fuel light comes on, fill up the tank and make a note of the gallons you pumped. Subtract the previous odometer reading from the current odometer reading and divide that number by the number of gallons pumped. Then let us know your MPG.

Also, to get an accurate picture of your overall average fuel mileage, you should do your calculations over several tankfuls and average the numbers. Your driving conditions will probably vary from tankful to tankful and one tankful of "bad" mileage does not mean the car gets that mileage for every tankful.

well, I only put in about 13.5 gals on a fill, so I am not really using the other two. But still, that is pretty bad!

Well after 3800 miles on my car and taking the same route to work for a while and changing it up slightly, I always run 93 octane BP in it and I am always consistent between 15.5 and 16.5 MPG. I don't take any highways, it is all urban, so to me that means all city. I sit at stop lights a lot and when I can I run it out to at least 6k, with a couple 7k-9k per tank, traffic dependent of course. I am not quite sure how it is so consistent as some weeks it seems I am stopped a lot in traffic and others hardly at all, but it always works out in the end. My WRX was down to 16-17 MPG when I traded it in, so it is not like I am taking a hit and my Wife's Tribute is usually somewhere between 18-20MPG. I have never, on any vehicle gotten what is listed on the sticker, I have always been 2-3 below on each, so maybe it is just me. But I sure enjoy the heck out of the car and at the end of the day that means more to me than how much gas goes in the tank.

Jammiman..where did you fill up at? Shell/Chevron/76 should be the only station you should use (Top Tier stuff). I have had ONE experience, where I used some other station (called Space Age), filled up, drove no more than 5 miles, and had 1/4 tank used up!!! I kid you not!!! SO, question is, did you use one of these stations? The other possibility is that when you ask for a fill up, the attendant did not fill it up properly (had a couple of instances where the pump would think it was filled up, but it wasn't - gas nozzle wasn't set properly to gauge the pressure in the tank). Anyways, hope this is the problem...

Forgot to comment..for those owners who have higher mileage on the odometer..have you tried redlining it often? I have read on the forum that as our car gets older, lots of carbon deposits, and the best way to clear that out is to ride it like you stole it!! HELL YEAH!!!

I fill up at chevron with 91 only. This is starting to bother me more and more as I read that everybody else gets 12.5 MPG at the worst. I pump my own gas, always. The only other thing that I can think of is that I do spend a lot of time in traffic. My drive to work is all highway, but so-cal highway, which is stop and go traffic. I also do make a lot of short trips. But with all that being said, I am still WAY below the average here. I bought the car about 6 weeks ago, and I love it too much to consider changing now. I should try the flash.

Oh yeah, GO48, I know how big the tank is in my car, without reading the manual.... thanks. I also know how to measure my MPG, I just thought that typing it all out was a bit pointless... thanks again. I don't mean to sound ungrateful, but you don't need to sound like the comic book store owner from the simpsons either!

Jammiman..what year is your car again? Are we talking about a new car or used one? If it is new, you should of gotten a letter from Mazda about the flash (assuming it falls in the build date). What about warm-up time, etc? I warm up initially no more than 2 min. then take off, keeping RPM below 3k until it is properly warm. All other start-up is less than a minute and I still get between 17-19 mpg with at least 4 start-ups/day (2 short-distance drives). So, to hear that you are getting that type of miles, would make me think you need to take it back to the Mazda dealer to have it looked it..swapping out plugs, etc.

Of course, the traffic for me is not nearly as bad as you are experiencing..so that could be a major factor on why you are getting such bad miles..nevertheless, I would have the dealers look at it and request they swap plugs and do a thorough inspection...hope that helps...

IC,

The car is a 2004. It is the 6 speed manual. It was purchased from the dealership, and certified. The person who had it before me (I found womans sunglasses in the holder when I test drove it) took perfect care of the car. It looks and feels brand new, so I don't think it is because of neglect. I usually warm the car for about 1 minute, it this really important with a rotary? It doesn't seem to be because it never gets cold here, so I thought 1 min was enough for the oil to get up into the engine.

I guess the only thing that I am worried about is that I may be damaging my baby in some way. I plan to bring it in this weekend because I have condensation in my drivers side tail, so I will ask about it when I get there. Thanks for the input,

Hmm..well, being an used car, although the dealer certified it, we are talking about a rotary engine..so..if the previous owner was rough on it and did not let the engine warm up properly before cranking it, that might cause the bad mileage. Another way to look at it is if the previous owner "babied" it..in which case, you will have alot of carbon buildup..and as I stated before, redlining it often will clear the carbon. Your best bet is to take it to the dealer and complain to them about the horrendous mileage. 15/16, ok..but any less would be cause for concern. Any rotary expert comment on this?

As for your condensation, that should be covered at dealer's cost. It is a known issue with the RX and I had BOTH of mine replaced because I had it. You might want to take photos of it if you can. I didn't at the time, but since Mazda dealers know about it, they did it without proof. However, by chance, it happened again before I had the appointment and I used my camera phone to take them. They didn't need it though..

As for engine warm-up..VERY important!!! Do NOT rev over 3.5k if your temp meter is not in the middle. Doing so will damage your apex seals!!! That is why to save gas, warm up a little (1-2 min.), then keep the rev low until the meter reaches the middle, then you can have your fun. I am surprised the dealer did not cover this???

Wow, thanks, the only thing the dealer mentioned is when moving the car (from one spot to another for instance) to let it run for a minute, or better yet, take it for a drive around the block, and when stopping, let it idle for 45 seconds before turning it off. He didn't mention any huge importance on warming it up. In the instruction manual

(section 5-4 point 6 "after starting the engine, let it idle for about 10 seconds"

and section 4-7 under "money saving suggestions" it says

"avoid long warm ups. Once the engine runs smoothly, begin driving"

I thought that said it all, I will keep that in mind, and ask about it this weekend. Is there anything else besides the oil check that I need to know about?
Thanks again,

You don't need to let it sit idle for 45 seconds when you get to your stopping point. When your temp meter is at the middle, you can just turn off the engine. HOWEVER, if you are moving your car for short distances, it is a good idea to take it around the block, park it, then rev up to 4k, let it idle back close to 2k then turn off engine: some people rev it up to 4k for 10 seconds, then turn off engine. This will force out any leftover fuel from the block (I believe that is what causes the engine flooding for the rotary).

Yes, you do not want long warm ups. That is what kills us rotary lovers!! Once your idle meter is roughly 1k (mine is at 1.2k after 2 min warm-up), you can go. Like I said earlier also, the first start-up should be a little longer. After that, you can just either let it warm for 10 seconds to 1 min..depending on your weather.

I check my oil every 1k. Mine usually eat between .25 and .5 quart per 1000 miles.

On the side note, do you know what type of oil your car is using? I switched over to Castrol 5w20 and got the better mileage. Before, the stupid dealers were putting in 5w30..not sure what brand of oil..but I gained 2 mpg with the lighter oil.

Only thing I can think of is to change your transmission and differential oil to synthetic. Alot of hard core owners are using either Royal Purple or Redline. I swapped my dino oil to Royal Purple and noticed shifting is alot easier and smoother. Since rotary in general generate alot of heat, synthetic oil for the transmission can take the abuse. I only had roughly 1500 miles on my car when I swapped out the oil, and man were they dark!

I have gotten a consistent 17 mpg for a 50-50 mix of local and highway driving. I had the opportunity yesterday to drive 300 miles, all highway, and got 22 mpg. My average speed was probably around 75, with windows and sunroof closed the whole time, and AC on for half of it. I use 89 octane. I have had my 8 for 15 months, and have only 8000 miles (lots of trips to the airport where it may sit for days, a short commute, long work hours, and a 4WD pickup as a winter alternate all contribute).

IC
I am using 5w20, it is warm enough here that I don't need 5w30. Thanks for the input about letting the rotor warm up, I looked into it, and you are right, it is a bigger issue than I thought. Thanks for the heads up, I'll re-post when I get back from the dealer.

Just checking in to post my lastest gas mileage figures. Every tank of gas meticulously logged since day one.

Enjoy,
Oranje

Just checking in to post my lastest gas mileage figures. Every tank of gas meticulously logged since day one.

Enjoy,
Oranje

That is incredible... thanks for sharing your meticulously documented information...

Just checking in to post my lastest gas mileage figures. Every tank of gas meticulously logged since day one.

Enjoy,
Oranje
Thanks Oranje. I have a bit over 10K miles on my '04 and my numbers are amazingly close to yours. My average for the first 7,600 miles was 20.58 mpg with a low of 17.58 and a best of 22.87.

Edit: Here's my mileage for comparison.

My numbers also are very close to those of Oranje & Go48. My average on the original motor (up through when it had to be replaced @ 58K) was 20.5. With the factory reman replacement motor the numbers are running around 19.75 post break-in. I'm also a New Englander, drive the car all year long, and have a mix of driving conditions and speeds.

On 89 octane I am getting 21.2/gal. On 91/93 octane I am getting 20.7. No complaints here. BTW it's a 2005 GT 6 spd with 19k on it and I bought it used. I let my car warm up for about a minute in the morning and I ALWAYS wind it up to 4k and turn it off. 90% of my driving is to and from work which is less than a mile from my house. I am only using mid grade gas now, I feel like the car runs better (but it could be my imagination). I don't really know what any of that means but I figured I would throw it out there.

My numbers also are very close to those of Oranje & Go48. My average on the original motor (up through when it had to be replaced @ 58K) was 20.5. With the factory reman replacement motor the numbers are running around 19.75 post break-in. I'm also a New Englander, drive the car all year long, and have a mix of driving conditions and speeds.
Wait, your motor was replaced at 58k miles? What happened? can you briefly explain what caused this motor replacement?

This is kind of odd. In city, i get crap for gas now w/ the turbo. Like, maybe 200 miles off of a tank. I was on the highway yesterday. Filled up right before the trip. I was among sum other friends w/ sti's and m3's. To put it nicely, I had several redline shifts or shifts above 6k under boost. After the night is done, and we're back in town, I look down and I have gone 203.0 miles, and still have well over a qtr tank left! That's awesome. It's like the car is saying it gets better mpg while driving in higher rpms!! Go figure.

i just got my car 2 weeks ago and mpg does suck. 13 gal and i got 190 mile or 200 max. average out to be like 14.7mpg. i do mix of hw and city. they advertise 18/24 but i havent even seen 17mpg yet. i would be happy if i even get 18mpg. how are some ppl in here getting 19 or 20mpg?

Damn, I'd kill for the mileage that Oranje, Go48, and VOODOO8 are getting.

I'm at about 13 MPG, and I drive an average mix of highway and city.

I keep the tires inflated, oil changed, car washed, Redline oil in the tranny and dif, and I occassionally rev to 9K to keep the carbon deposits to a minimum.

Nevertheless, my mileage bites. As you can see, I was for a while in the single digits, and most I've ever gotten is about 15. I gotta figure out what the deal is... I can't afford $200/month for gas.

Might check your cat - if its clogged it eats gas and power; also try different brand of gas - Mobil costs like smoke but it cleans up the system

Damn, I'd kill for the mileage that Oranje, Go48, and VOODOO8 are getting.

I'm at about 13 MPG, and I drive an average mix of highway and city.

I keep the tires inflated, oil changed, car washed, Redline oil in the tranny and dif, and I occassionally rev to 9K to keep the carbon deposits to a minimum.

Nevertheless, my mileage bites. As you can see, I was for a while in the single digits, and most I've ever gotten is about 15. I gotta figure out what the deal is... I can't afford $200/month for gas.

Try going for a Racing Beat intake. You get a little bit better milage.

If your running that rich you need more air.

My latest has been 22.5 HWY and 15.38 for spirted driving 2nd and 3rd gear.

I'm seeing the same poor gas mileage as you...13 to 17 at best. My car only has 1,500 miles on it so far. The other day I drove a full tank through on the highway and got just over 225 miles on that tank. I hope you are right about the mileage improving as the engine breaks in!

I get about 165 to 185 per tank full. My RX* has 18,000 miles on it. It has all the latest updates. Its been in the shop more times than any car I've owned in a short period of time.

I put Ester Synthetic from EthosNW $32 for two 12oz .but now they going up . If anyone find better price please post here.
I found result after I put Ethos . My MPG going up 1-2 Miles / Gallon . And still going a little bit up. So just for 1/4 cup to engine oil after oil change . It say on bottle use with 160 gallon of gas. they said put in gas tank . I think put in engine oil better . It will stay 2-3 month not for one tank . I think they want to sell more volume .My engine fill good . I used with Synthetic 5w30 or sometime 0w20 . Try it you will like it and tell some one else .
I forgot I drove 285 Miles didn't see low gas light ( almost come up I think ).

I put Ester Synthetic from EthosNW $32 for two 12oz .but now they going up . If anyone find better price please post here.
I found result after I put Ethos . My MPG going up 1-2 Miles / Gallon . And still going a little bit up. So just for 1/4 cup to engine oil after oil change . It say on bottle use with 160 gallon of gas. they said put in gas tank . I think put in engine oil better . It will stay 2-3 month not for one tank . I think they want to sell more volume .My engine fill good . I used with Synthetic 5w30 or sometime 0w20 . Try it you will like it and tell some one else .
I forgot I drove 285 Miles didn't see low gas light ( almost come up I think ).

For those interested in more information on this subject, check out the following link from Pure Energy Systems News: http://pesn.com/2005/04/12/6900080_Acetone_and_Ester/

Hi,

An update... I've been religiously monitoring my 8 fuel consumption since day 1. Of the ±3200km (2k miles) I've put on the car 80% are highway, the other 20% city driving. I do not drive especially fast, however I do like to use it like it's meant to at least once per ride, when entering an highway onramp or at a street light once the engine is warmed up... to take care of any carbon buildup :)

Here's a graph of my MPG and average MPG (progression of mpg, is it getting better or worse) to this day. I know, I have too much free time. [Long story short: best 18mpg, worst 11mpg]

I'm planning to take the car to the dealership somewhere next week to get the brake pads changed (20% wear and squealing like crazy, getting them replaced under recall if I can). I'm thinking about printing this graph and asking them to do a checkup on the car for possible reasons (O2, Cat, ECU) why my MPG is so low in comparison to what's advertised.

Do you think it is a good idea? Any of you had a similar experience that got you good results? Any reasons why I shouldn't do that? Any feedback appreciated.

I do know a sports car isn't about fuel economy but if I can get some improvement in any way... more money in my pockets.

Ok, I am getting my first car soon, and I out of all the others like this the best. But the Gas MPG obviously sucks! Because of that, and me being young and not very rich, would you all say get something else, or get this and deal with it. From what I am reading, this is very discouraging...

I'm seeing the same poor gas mileage as you...13 to 17 at best. My car only has 1,500 miles on it so far. The other day I drove a full tank through on the highway and got just over 225 miles on that tank. I hope you are right about the mileage improving as the engine breaks in!

what gear what speed?

Hi,

An update... I've been religiously monitoring my 8 fuel consumption since day 1. Of the ±3200km (2k miles) I've put on the car 80% are highway, the other 20% city driving.


describe your "80%" highway miles. be exact- what do you mean by this?

describe your "80%" highway miles. be exact- what do you mean by this?

I don't use the car daily since I go to work using the subway. My family lives 250km away (160 miles) so every now and then I spend a weekend over there, clocking 500km (320 miles) on the car each time.

So I could say that my car has spent 80% of its "miles" in 6th gear under 4k.

I normally don't use the cruise control but the usual traffic doesn't require me to change my speed much anyways. I tried twice to do the trip in 6th at ±3700rpm with the cruise control on and didn't see any MPG improvement (in fact the last ride I managed a record 18mpg and I drove in a more spirited way than usual).

The two big drops on my MPG curve happened when I spent a while without going at my family's place, therefore putting only "city miles" on the car between refueling. As you can see the MPG drops a lot, as low as 11 MPG. I can't even begin to imagine how much it would cost me to drive to work each morning in a car that drinks like a Hummer.

OK I have an update on my crappy mpg I will update this in a couple of threads since they are related to this. I had done the DIY throttle body bypass and since I was taking the car into the dealer this week I decided to put it back to stock. I didn't let the car cool down enough and sprayed coolant all over the interior of the engine compartment getting in the throttle body, the intake hose and generally just about everywhere except into the intake itself fortunately! I put everything back together after cleaning the throttle body and the intake out with carb cleaner.

The car seemed to be idling a bit high but seemed to be ok. I took it out for a test run with some redline runs and some cruise around town driving conditions to see how it was running. I get to a light and notice my car is idling at 1.5k rpms which is higher than normal after it's warmed up. It did slowly go back down to normal or 850 rpms but shot right back up and did the hunting idle thing. After a 10 min run with no change I go back home and give up for the night (at least she's running right I didn't kill anything.)

The next day I go over to Zoom44's to use his Hymee tool since a CEL was thrown and I could get the codes from him. We get number one code as MAF=low input... that tells me what I suspected which was the MAF was either dirty or damaged. We bust out the carb cleaner spray it down real good and put it back in. We clear the codes and start it up. No codes!!! Idle is perfect just like new. We drive it around and no issue. I was just about 60% in the gas tank (yes the Hymee tool tells you that too) and I had 73 miles since last fill up! Yes my mileage has been that bad. I have gone 25 miles since Monday night and I have used less than 1/8th of a tank!!!!! :wow: I didn't actually expect to see mpg (and most likely hp) gain from this.

I think mines been dirty for a long time and has been slowly getting dirtier until we come to today and the sudden change in my cars gas mileage. Maybe some of the other people having gas mileage issues could check this out since I wasn't throwing CELs before and I have taken it into the dealership for mpg issues a number of times!

I will keep everyone updated on my next fill-ups to see if this continues.

Hello, new to this forum. I own a 2005 Mazda 3 and I've seen people complain about gas mileage on the 3, specifically the 2.3L hatchback, on another mazda forum. Worst mileage was about 19 mpg and the best was about 30. I'm getting about 27 mpg with a mix of city highway 50/50 and I live in a city with tons of hills, traffic, stoplights/signs so I really can't complain to much.

I also own a 1990 mustang 5.0L V8 and I'm getting about 16-17 mpg overall with some spirited driving here and there. I just find it odd that a small rotary would use so mush gas. Don't get me wrong, I love rotary engines and I went on a few rx8 test drives and they're a blast to drive but can mazda do something about the fuel economy. If it was any better I'd probably would have bought an rx8 instead of my MZ3.

I just bought my 8 last week and the previous owner told me he had traded it in due to poor gas mileage. He claimed that he only got 15 mpg even cruising on the highway on a 250 mile trip using cruise control. I don't know what he was doing wrong.

I just went on a 530 mile road trip that included 100 miles of pure highway, roughly 250 miles of secondary roads allowing 45-55mph (5th or 6th gear) with significant slow-downs or complete stops every 15-20 miles, and the rest of the miles touring around in Acadia National Park with lots of stops, hills, mountain roads and trips into a congested town for meals, etc. For the entire trip, there were two people in car and we either had the windows open or the A/C on (probably half and half on those). I opened the throttle liberally from time to time.

I averaged 22.4MPG for the trip. Is my car blessed?

Just returned from Las Vegas to Los Angeles. Left at 3AM and arrived, 258 miles and 14.8 gallons of 91 oct later, at 6:15AM. That's 17.43mpg at an average of 79.4mph. Didn't make any stops, so don't know where the avg. mph went. (Did stop briefly after passing Ken Gushi's drift car trailer on the way back from the D1 Exhibition, but only to let him catch up, so my son could check out their rig, so maybe "adjusted" avg. = 81.9mph?.) Most of the time it seemed I was at 85-95 with fairly long stints at 100 or 80. Btw, I usually run 87 oct, but on the way there, in 116 ambient, I'd get pinging anytime above 5k, so switched to the slower burn fuel.

Over 50,000km
Best - 10.4L/100km or 22.6 mpg
Worst - 29.9L/100km or 7.9 mpg - lots of beeps
Average - dropping 3 best and 3 worst - 13.97L/100km or 16.84mpg
Winters, Summers, Hwy, City.
Doesn't really matter - only way to achieve better than 20mpg is by having the car completely warmed up, and running on the hwy with a tail wind, or drafting another car.
Fuel efficient the rotary is not.
Makes you appreciate old push rod technology that gets 25+ mpg in the C6
Looking at it percentage wise - a C6 Z06 has 505hp - over 2x the RX-8, weighs approximately the same, and gets 50% better fuel economy.

You pays to be different.
Shell, Esso, Sunoco - 91 all appear the same over many fillups.
89 is the lowest I've gone.

Just finished two round-trip highway jaunts of 260 miles each. Almost all interstate with speed averaging 78 mph. Result was 25.4 mph. Around town I get about 18. Run 93 octane all the time.

I've seen many good ideas here in terms of what people with gas mileage problems should be looking for. I think we should also focus on a long checklist of what the Mazda tech. should look at.

I kinda of have the theory that Mazda dealers will avoid replacing parts or doing any work for free, despite the warranty. If a customer says, "Hey, I get really, really suck gas mileage, so do something". I think too many Mazda dealers are like, "Yeah so. Too bad. You poor baby." etc, etc, etc... and maybe some shoulder shrugs. It appears they will just try to "wait you out". Do nothing to very little, in the hope that you get tired of complaining and go away.

I think the RX-8 owner may have to be VERY specific about the list of things that they want the Mazda dealer to check and verify are working properly.

Here are things that I've seen around here and thought of to help the RX-8 gas mileage situation for various owners:

1. Verify your calculation point. Are you running the RX-8 all the way dry or are you re-fueling when the yellow light comes on??? If you are waiting until the light comes on, than you may still have 1 gallon to 2 gallons of fuel left (so you may have used 13 or 14 gallons as oppose to 15 gallons). Don’t make the mistake of calculating that you have run the tank dry from that point when you do the math.

2. Check your oil? Changed your oil filter? Are you in a hot climate? Think about getting the fan mod? How many oil coolers do you have?

These are important, because they seem to be factors. I changed my oil filter from the oem one to a Mazdaspeed oil filter and picked up 1-2mpg. I had been checking and adding oil, but remember to change the oil filter at the designated time. Actually, you may want a high performance oil filter while you are at.

If you are in a hot climate, there appears to be issues with temperature. A 2nd oil cooler (if you have one of the ones that don’t have it), fan mod (search for Looking for a cooler running RX-8? Or go to http://www.mazsport.net).

3. What is the octane level of the gas you are buying? Who are you getting your gas from?

The RX-8 likes 91 Octane or better gas. If you put in lower octane than you are supposed to than that may be the reason why you are getting lower than expected gas mileage. If you insist on using low octane gas to save money, than consider at least adding an octane booster. I’ve used octane boosters with Xylene, with great success. Xylene also burns well, without leaving a lot of deposits, like other octane boosters.

Note/Edit- There seems to be some debate about which is the better octane level. It seems higher Octane is better for performance, but maybe not for gas mileage. Lower Octane, but high enough not cause knocking, may be better for gas mileage. I think the best bet is to stick with Mazda's Octane rating when in doubt, but experimenting with different gasoline from different vendors and with different Octane ratings may help or show something.

I’m getting better gas mileage when I fill up at certain gas stations. I’m not clearly understanding this myself, but it appears the additive package from different gasoline companies are… different. Thus the RX-8 performs better with gas from certain gas companies. I think you need to test this on your own, as oppose to me telling you who to go to and this may vary from state to state or from country to country.

4. You need to rev your RX-8 to at least 6K every day/every other day (higher for the M/T). Have you been doing this?

Some people are babying their RX-8 way too much. This can be hurting your engine, as oppose to helping it. The RX-8 rotary engine is different. Consult this forum or your user manual (just good to read anyway) for more info.

I’ve also seen some more specific advice in this forum, but I’m having trouble locating it right now, but soon as I do than I will let you know. But the above would be a big start for people having trouble with their gas mileage.

More....

5. Check your MAF ( Mass Air Flow) sensor/meter. Here is a link to a part for cost estimate and a reference.... http://www.drivewire.com/mazdaparts...wmassmeter.html

6. Check your Catalytic Converter. It appears that its possible for them to become clogged or damaged in various cases without the a CEL light going off. This can be the cause of an RX-8 eating too much gas or not accelarating "properly", so should be checked by an Mazda dealer.

7. Check your PCM (Powertrain Control Module) / ECU (Engine Control Unit) . It may need to be re-programmed/flashed. It may be injecting too much fuel when your engine is started an causing carbon build up and other issues. It appears that various RX-8 have problems with their ECU / PCM.

Note- results of having the ECU / PCM flashed appears to vary.

8. Check Air Filter or consider buying Cold Air Intake. May improve gas mileage.

9. Check O2 sensor. A defective one can cause overly rich mixture.

10. Another factor worth mentioning is customer expectations. The RX-8 is a sports car. Gas mileage in most sports cars SUCK. You should expect 17 to 24 MPG from the RX-8 and most other sports cars. I think RX-8 users complain a little more, because the price range and the “cool factor” means people buying the RX-8 might have bought an economy car, but choose the RX-8 after looking at it. These same people that are used to a 4 cylinder econo car then have a hard time understanding how to take care of a rotary engine or anything that will get less than 25 MPG. Well, the RX-8 is for FUN. If you don’t want a cool looking and fun to drive sports car, than go ahead and get an econo box and call it a day. Otherwise, I say, go over a list of thing that may be causing poor gas mileage in your particular RX-8. Also, see your Mazda dealer and make sure they check and confirm that there is nothing wrong with your car.

I think we should keep adding to the list, until we got something very comprehensive. Maybe it could resolve the gas mileage problem of a significant percentage of RX-8 owners.

Update... ??? Sorry everyone I kinda neglected the update. I did get good gas mileage for about 2 weeks. Now it seems to be going back. Maybe I should check the MAF again? Who knows, but either way I did get the latest flash and that seemed to make a little difference as well since I'm not having any more pinging or hard runs off the line.

Am I the only one getting the expected mileage? Just a bit over 3000 miles so far, getting about 17 mpg around town, 23 highway (usually a tad over). IMHO, that's right on the marks for a car rated at 18/24.

Had the recall done last week, and just refilled the tank. Driving around town, and it came out to 17.5. Pretty much the same as usual. I've got a couple of hundred mile trip coming up tonight (headed to Lincoln Speedway, Abbottstown, PA to watch the big 40 lapper) so I'll get a benchmark on highway.

06 MT, build March 06.

Ken

I've now got a LOT of highway miles on my car as a proportion of total miles(well over half the 8000-ish now on the car), and having recently done 2000mi in the space of about 48hrs (after doing over 1000mi on a trip two weeks prior), the typical tank was about 22mpg +/-1.5 with the AC on the whole time doing 72-78mph.

I was doing about 24 with minimal AC in cooler weather last spring, so it looks like the AC and high ambient temps knock off about 2mpg. "City" mileage is all over the map, from a low of 13.5 to a high of 17 on tanks that are all-local and never saw the highway.

My overall mileage at this point is 19.4.

I changed my oil filter from the oem one to a Mazdaspeed oil filter and picked up 1-2mpg.
Oh, come ON....

Oh, come ON....

I track my gas mileage and did see an improvement. I think your objection might be that you think I'm recommending a mazdaspeed oil filter. I'm NOT. I'm simply saying to replace it, if necessary, and check other things. The oil filter was changed along with an oil change.

as far as #1 goes, all you have to do is reset the trip odometer at fill up, and you can fill up whenever you feel like. Miles on trip, and gallon on pump = mpg.

I think a lot is driving style. Too easy on it....... mpg sucks. To hard on it...... mpd sucks.

I think most is the former, people its got a 9K range, 6K aint gonna hurt nothing. And its not like you have to floor it everytime, but letting the engine stretch its legs definately seems to help everything.

Don't worry I rev it 'til it beeps often enough... you can ask Zoom44 about that. I aint scared of a little red line. That said I still don't see the gas mileage some are seeing. I have even tried the grampa style every now and then... still isn't working.

I track my gas mileage and did see an improvement. I think your objection might be that you think I'm recommending a mazdaspeed oil filter. I'm NOT. I'm simply saying to replace it, if necessary, and check other things. The oil filter was changed along with an oil change.
My objection has nothing to do with your recommending a Mazdaspeed filter... It has to do with the suggestion that an oil change would improve your mileage by about the same amount as not using your air conditioner. Unless you've got molasses in your oil lines, an oil/filter change should have no noticeable difference in gas mileage.

has anyone experienced decreased mpg after the recall flash? (what letter are they on now?) ive tracked every tank since 3.04 and have gotten to the point where im usually in the 18.5-19.5 range with easy driving (keeping it under 3750rpm.) but since the flash ive dropped to around 17mpg, and ive been driving the car pretty damn easy this past month or two. i actually only had about 5mi on the tank when i went in for the flash, and immediately it went down, im about five tanks in now and its consistent. on a trip down to cincy that i ususally get 20-22mpg and got 18, and that was nearly 100% highway crusing at 70mph

YES. I went from 22 or so for freeway driving down to about 19.5 or so. I'm going to go to the dealer- the car also now stumbles. I'm wondering if there's a bad plug in there.

I have just gotten the recall flash so I updated my spreadsheet and came up with the following MPG numbers until this point:

July 2003 Port Flash - 6,567 miles 14.9 MPG

M Flash - 8,375 miles 16.4 MPG

R Flash - 6,955 miles 16.5 MPG

I do mostly in-town driving and I drive in a spirited fashion. My car is totally stock.

I think i got a defective RX8. Just bought an automatic 2 months ago and i fill the tank with exactly 15 gallons of gas but i am getting a maximum of 180-190 miles. Its unherd of. I was so pissed i took it back to the dealer ship and they just flashed it. I don't think it has made a difference and i am thinking of invoking the lemon law and asking them to replace the car and maybe try and get a manual one instead. I am not sure, i dont think they will do much to fix this car. I do like it though. I just wish it worked properly. Has anyone got any suggestions, the car has total 1800 miles on it and i got it with 800 miles on it.

Not sure if this is pure coincidence, but my mileage dropped about 1-2 after the flash (was @18-20mpg), but when I tried the brake 20 times pump reset, it appears to be back to what I was normally getting. I've been keeping tabs on the mpg for about 6 weeks now..so..am pretty confident that that might work. Basically, turn on the your car (not start it) to pre-ignition, pump the brake pedal 20 times before 10 seconds(?), you'll see your oil gauge drop, then turn your car off, then back on and ignite your car. I think this procedure reset your car's to learn mode or something..anybody with better details, please input :)

As for the auto vs. manual Nemesis..go back and tell them you want to change it to the manual..auto is not as fun as the manual..whether you can do it without paying a minor fee..

YES. I went from 22 or so for freeway driving down to about 19.5 or so. I'm going to go to the dealer- the car also now stumbles. I'm wondering if there's a bad plug in there.

For as long as I owned the car I got consistently between 19.5 - 20.5mpg. After the recall reflash it immediately went down to 17mpg. Dealer service manager didn't seem to believe me and chalked it up to cold weather. I've driven this car every winter since 2003 and never encountered this magnitude of mpg loss. This and the constant CEL have been the last straw for me. I just traded my RX8 in on an Acura TSX. Not as exciting, but I'm certain it will be waaaaay more reliable with much better mileage!

thanks icyur2. I wil try that but i will definately talk to the guy, infact give him a call right now and ask him what the deal is with this car and what he needs to do to replace it.

Finally I managed to get the gas mileage below 10l/100km.

It was 9.63L/100km (24.43MPG). 20% City/80% Highway

How to get this mileage:

Talk with a self phone while driving, then you'll barely exceed 95km/h (60MPH) and in city drive faster [minimum 65km/h (42MPH)] so you can always drive in sixth gear.

Car has 50000km (30000 miles) on it.

It was quite a pleasure to see that tripmeter shows 540km (337miles) before the yellow light came on :)

Haven't checked the mileage for a while. Drove from Indy to Chicago and back this weekend, about 450 miles round trip. Averaged about 80mph on the highway with some speeds a bit higher. Got 19.75mpg. I have 46,000 miles on the 8 now.

9.63L/100km? That's Amazing!!
I have been logging for over 60K now, and have yet to break 10L/100km.

My record is over 29L/100km - lots of beeps! I've seen posts of 33L/100km!

Best is 10.4L/100km

Average 13.96L/100km over 61,293km
16.85 mpg (US gallon)

Not going to win any green awards.

How a 3000lb car with 180hp at the wheels gets such pathetic economy must be a function of how rich the renesis really runs - pipes are carbon black after 100km.

There is no reason this car should not get 9L/100km on the hwy, and around 11L/100km mixed.

9.63L/100km? That's Amazing!!
I have been logging for over 60K now, and have yet to break 10L/100km.

My record is over 29L/100km - lots of beeps! I've seen posts of 33L/100km!

Best is 10.4L/100km

Average 13.96L/100km over 61,293km
16.85 mpg (US gallon)

Not going to win any green awards.

How a 3000lb car with 180hp at the wheels gets such pathetic economy must be a function of how rich the renesis really runs - pipes are carbon black after 100km.

There is no reason this car should not get 9L/100km on the hwy, and around 11L/100km mixed.

I believe, that it is possible to go even lower in the same conditions.

9.63 was accomplished with winter tires, and I got nearly the same mileage (10.1L/100km) with summer tires a week ago, but my average speed was 110 instead of 90.
When I had my winter tires, my mileage at the 110km/h was never below 11L/100km, it was more like 12L/100km.

hey guys i got an 04 rx-8 with about 23000km/14200miles on it.

I am getting 265km/165m on easy driving per tank
and 240km/150m on hard driving per tank

My dealer does not deal with rx-8's very often and my car is still warrantied, what should i be asking my dealer to do cause i have told them about this problem and they seem to be clueless about everything with this car.

R.J.K.

*I am not an engineer, have no technical training on automobiles whatsoever-maybe this is far fetched -just using common sense and looking at the whole big picture here.

So.................what do you all think?


Years ago, I worked for a Ford dealership and was sent to many factory trainings during the days of the earliest electronic engine controls. I don't recall what version of EEC Ford was on at the time, but our instructor was explaining a switch hidden under the dash on SVO mustangs that allowed a performance mode. I'd think this would be an excellent feature for the RX-8 save for the hidden part.

Sort of a Wild/Mild switch if you will. Daily driving would be the normal mode while the ability to enjoy the car's potential could be easily turned on. Adaptive learning by the ECU for driving habits is a joke. Especially with more than one driver that often uses the car.

As it is, our cars most likely run far richer than need be as evident by the black deposits on our exhaust tips. Perhaps this would even reduce the flooding issues.

Finally I managed to get the gas mileage below 10l/100km.

It was 9.63L/100km (24.43MPG). 20% City/80% Highway

How to get this mileage:

Talk with a self phone while driving, then you'll barely exceed 95km/h (60MPH) and in city drive faster [minimum 65km/h (42MPH)] so you can always drive in sixth gear.

Car has 50000km (30000 miles) on it.

It was quite a pleasure to see that tripmeter shows 540km (337miles) before the yellow light came on :)

Finally a new record :Eyecrazy:
630.9km & 58.16L => 9.22L/100km (25.51MPG) 10% city/90%highway
now the car has 55569km (34536miles) on it.
Also last time I had winter tires 17" rims now I had summer tires 18" rims.
Yellow light came on @550km

Beat this :)

I've seen many good ideas here in terms of what people with gas mileage problems should be looking for. I think we should also focus on a long checklist of what the Mazda tech. should look at.

I kinda of have the theory that Mazda dealers will avoid replacing parts or doing any work for free, despite the warranty. If a customer says, "Hey, I get really, really suck gas mileage, so do something". I think too many Mazda dealers are like, "Yeah so. Too bad. You poor baby." etc, etc, etc... and maybe some shoulder shrugs. It appears they will just try to "wait you out". Do nothing to very little, in the hope that you get tired of complaining and go away.

I think the RX-8 owner may have to be VERY specific about the list of things that they want the Mazda dealer to check and verify are working properly.

Here are things that I've seen around here and thought of to help the RX-8 gas mileage situation for various owners:

1. Verify your calculation point. Are you running the RX-8 all the way dry or are you re-fueling when the yellow light comes on??? If you are waiting until the light comes on, than you may still have 1 gallon to 2 gallons of fuel left (so you may have used 13 or 14 gallons as oppose to 15 gallons). Don’t make the mistake of calculating that you have run the tank dry from that point when you do the math.

2. Check your oil? Changed your oil filter? Are you in a hot climate? Think about getting the fan mod? How many oil coolers do you have?

Is your oil low???

These are important, because they seem to be factors. I changed my oil filter from the oem one to a Mazdaspeed oil filter and picked up 1-2mpg. I had been checking and adding oil, but remember to change the oil filter at the designated time. Actually, you may want a high performance oil filter while you are at.

If you are in a hot climate, there appears to be issues with temperature. A 2nd oil cooler (if you have one of the ones that don’t have it), fan mod (search for Looking for a cooler running RX-8? Or go to http://www.mazsport.net).

3. What is the octane level of the gas you are buying? Who are you getting your gas from?

The RX-8 likes 91 Octane or better gas. If you put in lower octane than you are supposed to than that may be the reason why you are getting lower than expected gas mileage. If you insist on using low octane gas to save money, than consider at least adding an octane booster. I’ve used octane boosters with Xylene, with great success. Xylene also burns well, without leaving a lot of deposits, like other octane boosters.

Note/Edit- There seems to be some debate about which is the better octane level. It seems higher Octane is better for performance, but maybe not for gas mileage. Lower Octane, but high enough not cause knocking, may be better for gas mileage. I think the best bet is to stick with Mazda's Octane rating when in doubt, but experimenting with different gasoline from different vendors and with different Octane ratings may help or show something.

I’m getting better gas mileage when I fill up at certain gas stations. I’m not clearly understanding this myself, but it appears the additive package from different gasoline companies are… different. Thus the RX-8 performs better with gas from certain gas companies. I think you need to test this on your own, as oppose to me telling you who to go to and this may vary from state to state or from country to country.

4. You need to rev your RX-8 to at least 6K every day/every other day (higher for the M/T). Have you been doing this?

Some people are babying their RX-8 way too much. This can be hurting your engine, as oppose to helping it. The RX-8 rotary engine is different. Consult this forum or your user manual (just good to read anyway) for more info.

I’ve also seen some more specific advice in this forum, but I’m having trouble locating it right now, but soon as I do than I will let you know. But the above would be a big start for people having trouble with their gas mileage.

More....

5. Check your MAF ( Mass Air Flow) sensor/meter. Here is a link to a part for cost estimate and a reference.... http://www.drivewire.com/mazdaparts...wmassmeter.html

6. Check your Catalytic Converter. It appears that its possible for them to become clogged or damaged in various cases without the a CEL light going off. This can be the cause of an RX-8 eating too much gas or not accelarating "properly", so should be checked by an Mazda dealer.

7. Check your PCM (Powertrain Control Module) / ECU (Engine Control Unit) . It may need to be re-programmed/flashed. It may be injecting too much fuel when your engine is started an causing carbon build up and other issues. It appears that various RX-8 have problems with their ECU / PCM.

Note- results of having the ECU / PCM flashed appears to vary.

8. Check Air Filter or consider buying Cold Air Intake. May improve gas mileage.

9. Check O2 sensor. A defective one can cause overly rich mixture.

10. Another factor worth mentioning is customer expectations. The RX-8 is a sports car. Gas mileage in most sports cars SUCK. You should expect 17 to 24 MPG from the RX-8 and most other sports cars. I think RX-8 users complain a little more, because the price range and the “cool factor” means people buying the RX-8 might have bought an economy car, but choose the RX-8 after looking at it. These same people that are used to a 4 cylinder econo car then have a hard time understanding how to take care of a rotary engine or anything that will get less than 25 MPG. Well, the RX-8 is for FUN. If you don’t want a cool looking and fun to drive sports car, than go ahead and get an econo box and call it a day. Otherwise, I say, go over a list of thing that may be causing poor gas mileage in your particular RX-8. Also, see your Mazda dealer and make sure they check and confirm that there is nothing wrong with your car.

I think we should keep adding to the list, until we got something very comprehensive. Maybe it could resolve the gas mileage problem of a significant percentage of RX-8 owners.

Update:

2. Consider the type of oil you are using.

5w20 vs 5w30 or heavier. The lighter oil may give improved gas mileage. If you are using 5w20 dino and not synthetic, than I would consider keeping it 5w30. 5w30 dino should shear down to become thinner and lighter over time. Synthetic would do a better job of keeping its weight over time.

8. In addition to CAI, look into Mazsport hardware mod to turn the fans on earlier and keep the engine cooler. http://www.mazsport.net/store/page9.html


11. Check your radiator coolant.

Is there rust? Does it need to be changed? What's the water to coolant ratio?

Consider using a product like Red Line Water Wetter

http://www.redlineoil.com/products_coolant.asp?subCategoryID=4


12. Consider using a fuel additive like Red Line SI-1 Complete Fuel System Cleaner to remove carbon and deposit build up. The Red Line Fuel additive is also a lubricant and anti-rust as well. It can also be used "like" pre-mix.

I believe its use improved my gas mileage.

http://www.redlineoil.com/products_fueladditives.asp?subCategoryID=11

I have subscribed to this thread as I am very interested in what other owners have to say about their gas mileage and ways they have tried to improve it. I'm amazed at how low mpg many drivers say they are getting. I live just outside the suburbs, so I have a mile or two of country road driving (at 55 mph) and then city driving with a number of traffic lights and stops at intersections. I have had my stock RX8 for 5 months now and have kept very good records. I use Shell 93 octane most of the time (same station 80%). I check my tire pressure and just completed the 15K oil change, etc. All updates have been done. I am not an aggressive driver, nor do I baby it. I'll use the gas pedal when on the ramp to enter the highway. Will zoom-zoom a bit when I have friends in the car with me (show-off).

After last fill up, got 18.36 mpg (with the driving described above). Two road trips I took with 90% highway I got 23.17 and 24.84 mpg. I am planning on a 3000+ mile road trip this summer and will keep detailed records. I'm hoping to get over 24 mpg!

Let me ask this? I've never used Red Line SI-1 Complete Fuel System Cleaner. Have others used it and with what results? Are there any concerns using this product in a rotary? I'd like to get my engine ready for the long road trip and this seems like a good idea to me. OTHER THOUGHTS?

Finally a new record :Eyecrazy:
630.9km & 58.16L => 9.22L/100km (25.51MPG) 10% city/90%highway
now the car has 55569km (34536miles) on it.
Also last time I had winter tires 17" rims now I had summer tires 18" rims.
Yellow light came on @550km

Beat this :)

Pushing your luck there!
I'm surprised you didn't run out!

That little yellow light to me means - QUICK - NEED FUEL.
The light comes on around the 50L mark.

Pick up problems at around 40L

Run out of fuel problems around 56-57.

I always fill it to the first pump click - doesn't like much more than that

9.22L/100km :bowdown:

I've finally managfed to go through a full tank of gas without revving past 4000rpm; It was torturesome to say the least. However I was quite shocked to see the results. 400km on 52 l of 94 Octane Chevron. That works out to 13 l / 100kms on city driving. SO the mazda figures are actually achieveable. I think it all has to do with how heavy your right foot is. Can't wait to see what i get for Highway consumption when I have the chance to take a long trip.

Pushing your luck there!
I'm surprised you didn't run out!

That little yellow light to me means - QUICK - NEED FUEL.
The light comes on around the 50L mark.

Pick up problems at around 40L

Run out of fuel problems around 56-57.

I always fill it to the first pump click - doesn't like much more than that

9.22L/100km :bowdown:

Tank actually holds 61 litres, so I could have gone for antother 20km, before the fuel would have run out :)

Yellow light means - QUICK - NEED FUEL only when You are doing a little race.

From another Estonian thread I read about a guy, who calculated, how much a RX-8 would consume fuel, when I needs to drive for 700m (400m full acceleration and 300m easy slowdown).
Test showed, that the 8 consumed 0.8L fuel, which makes 144L/100km or 1.63MPG :)

i have a around 30k millege 04 6 speed rx-8...i only get 180 mpg...is this not suppose to happen?

Hey All,

'04 RX-8 Stock, 50Km, here's what I got:

Driving the way it should (wind'er up in the corners, don't let old people pass you)
- 16.5L/100KM
- 14 MPG

Driving Miss Daisy
- 11.5L/100KM
- 22 MPG

Both roughly 20% city, 80% highway.

Don't think I've ever seen more than 450KM/tank, but the way I drive I avg 330KM/tank in the summer, 290/tank in the winter.

I get 19-20 mpg,average,on my 04' RX with 31K. I run Elf 5w40 and it seems to run better than 5w30,but the gas milage has remained essentially the same. The best I ever got was around 22mpg,and that tankful included a nice long run at +130 mph on rt.89 in Vermont,a couple of years back.

Holy crap where did all my posts go??

Hey everyone, been reading this forum since I got my car about a year ago. Did not feel like posting before I read enough, and before I had something new...I hope!

I was flipping through the TV channels and came across a show where they build muscle cars. This show had a segment where they test products to see if they actually work. They tested a Fitch Fuel Catalyst (in a controlled environment) and got improved gas mileage and horse power. Anyone hear of this product? Anyone have one installed?

I have an email into the company to see which product would work best with the RX8, since they don't have the car listed.

http://www.fitchfuelcatalyst.com/index.cfm

BTW, I can get 23 MPG when I drive like a grandma. I have an '07 AT with a drop in K&N filter.

I've had my '04 AT for over three years now; I've got 50K miles and I'm averaging just over 22 mpg (roughly 60% hwy, 40% city, semi-agressive driving). I change oil religiously and it's been super reliable.

You're AVERAGING 22 mpg? Wow. I've never even seen 22 mpg. Best I got was 20.5 all highway.

You're AVERAGING 22 mpg? Wow. I've never even seen 22 mpg. Best I got was 20.5 all highway.

If you shift around 2,000 rpms you can do it...that's how I got 23 mpg. Not too fun to drive but saves some gas...do it when Grandma is in the car or when you are in stop and go traffic. I tried to do that again on the next fill up but couldn't resist and ended up getting 22 MPG. And no... I don't drive like that all the time, I was trying to see the best MPG I could get outta the car since I see all these bad reviews on the car claiming 12-14 MPG.

The only thing I've done to the car is a drop in K&N. It's cheaper to get the oil changed at the dealership (believe it or not) and they put in fuel additive every 6,000 miles.

So no one has heard of the Fitch Catalyst.... I'm still waiting on them to email me back on which part I should use. I bet they will tell me to use the thing you drop in your fuel tank so I don't have to cut my fuel line and ruin my warranty. I gave the info to my buddy at the Mazda Dealership..he was going to look into it as well. I suppose if it's cheap enough I can try it. I calculated the savings of even gaining .5 mpg and it's worth it (depending on how many more miles you plan on putting on your car), but that's based on the cost of the unit you place in your fuel line ($177). I'm pretty skeptical but doing some research doesn't hurt.

I've never heard of the Fitch Catalyst. It sounds like snake oil but doing research can't hurt.

I guess I can see getting 23 if you shift that low in the range, but you're going to build-up carbon like crazy. And Kdlunge is saying he gets 22 with semi-aggressive driving on the city and highway- to me that means the needle is sweeping past 2k regularly.

Ok, got this message from Fitch. If you look at the last page of the horse power PDF it shows the savings as gallons per hour....not exactly MPG. Maybe that's their trick...I would call and double check on the part number since our car isen't listed. I'll go see my buddy at the dealership to check about warranty and about the product. I also know a guy who used to work on Nascar engines, I'll try and see him as well. The only reason why I'm looking is because of that Horsepower Show...but they might get incentives for promoting the product. It's a long shot, but a $100 long shot.

Thank you for your inquiry regarding the Fitch Permanent Fuel Treatment Device. You must have seen the Horsepower TV segment that performed a dyno evaluation of the Fitch Fuel Catalyst. Just by adding Fitch, Horsepower TV recorded improvements in horsepower, torque and fuel economy on the test engine supplied by GM (427 ci LS7).

For a limited time and only available through us, the Manufacturer, the Fitch Permanent Fuel Treatment is now available for $99.95 for all basic models with the prefix of F3, $149.95 for models with prefix F4, $169.95 for models with prefix F5 and $199.95 for models with prefix F75. The correct application for your vehicle is Fitch model F3624.

Warranted for the lifetime of your car while you own it, the Fitch easy to install “Bolt on Kit” will SAVE YOU MONEY.

You may order on line by going right to this order page for your part # F3624 http://www.fitchfuelcatalyst.com/cfm/finder.cfm?list=0,2,2289,2290,2291&drill=2292

OR you may contact our toll free number 1-888-881-2774 and a sales representative will assist you. Be sure to mention “Horsepower TV” when you call to get your Special Offer price. If you order from our website, type the words “Horsepower TV” under the section “OTHER NOTES” and this will guarantee your special price. The website will show our regular price but as long as you state the “Horsepower TV” in OTHER NOTES SECTION, our processing department will qualify you for the special offer. Hurry before this special is over and you have to pay regular price for your application - $177.45 – Don’t Miss This Offer. Spend less today and if you are not satisfied, simply return for a refund. If you have any further questions, please feel free to contact me.



· Improved Fuel Economy (1 – 2.5 mpg)
· Increased Octane or Cetane
· Improved Performance – Horsepower & Torque
· Allows vehicles requiring premium fuel to operate on at least 1 or 2 grades lower w/o sacrificing performance (saves .20 - .40 cents per gallon)
· Reduced Emissions (less oil changes per year – cleaner oil) (Can save $25.00 - $100.00 per year depending of oil change frequency)
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· 90 day money back guarantee

Do your part to save energy and reduce pollution in your community

Join The Fitch Green Team!!!

If you experience any website difficulties please call our toll free number 888-881-2774.

Take care,

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Customer service/Tech Support
Advanced Power Systems Int'l
Toll free 888-881-2774
Direct 860-496-7776
Fax 860-496-7626
www.fitchfuelcatalyst.com

I can confidentially say that I get 13mpg on average.

I consistently get about 20MPG...mostly highway/suburban driving.

Highest: 21.9MPG
Lowest: ~16MPG

I can confidentially say that I get 13mpg on average.

I do little to no highway driving. I get 16 MPG on average. Some weeks it's 15, some weeks it's 17.

16 AVG.

Once I did all highway driving on a road trip. I got 20.5. That's my record.

I don't shift at 2k though. I shift between 5-7 on average. I almost never shift below 5k unless the car isn't warm yet. I'd rather get low mpg then carbon build-up or not have fun while driving.

Sabo- This thing doesn't sound like a good idea to me. I wouldn't add something like this without experienced users weighing in on their results. Horsepower TV doesn't really count. A lot goes on behind the scenes, and their test wasn't long term. If you want to be a test subject, no one would fault you, but that's a considerable gamble.

I get 17-18 mpg around town driving (60% city/40% country driving) and 23-24 mpg on highway driving. I think I can get 24-25 mpg if I do 100% cross country highway road trip. I'm pleased -- but sure would like to get more or be able to use 87 octane without lose of performance. I'm not a granny driver, but also not super aggressive.

I'm interested in hearing more about the Fitch Fuel Performance Device. Would like to hear from those who have the technical expertise give their thoughts. I'm leary of the manufacturer making claims.

Hard cold facts attached for 2004 MT purchased 46 months ago:


Purchased 1,661 gallons of Shell 93
Average price paid: $2.52 a gallon
Total fuel cost: $4,190
Total mpg 20.4
Fuel cost per mile .124 cents


Cheers,
Oranje

hey guys just signed up tp the site i bought my rx8 used with about 50 k on it, im noticing terrible gas milage. It has standard tanks at 15.9 gal tank but i can only drive about 100 miles on the tank......seriously whats the deal??? whats wrong do i have a hole in my tank or what? Anyone knows anything the input would be great!! Thanks

Does anyone know if the newer ECU flashes are helping MPG at all?

Or the canzoomer maps, i've heard some of those can help MPG maybe not AMAZINGLY but still 2-3 mpg is significant.

hey guys just signed up tp the site i bought my rx8 used with about 50 k on it, im noticing terrible gas milage. It has standard tanks at 15.9 gal tank but i can only drive about 100 miles on the tank......seriously whats the deal??? whats wrong do i have a hole in my tank or what? Anyone knows anything the input would be great!! Thanks

LOL @ post.

I just came back from NC to FL. 2004 with 57K, premix.
Highway driving avg 90mph, 19.7MPG.
Highway driving avg 80mph, 21.7MPG
I did this going up and coming back, numbers were almost identical +/- .1MPG (80MPH through FL/GA, 90MPH through SC/NC).
Mixed 'spirited' driving I get 17~18MPG in FL.

Just my numbers,

A

The highest i ever got on a full tank was 238 before the light came on, that was when i first got the car, now ive been getting about 200 miles before the light comes on. I'm hoping that the tune up that im going to get soon will help. I just want 220 and ill be happy.

tank #1: 200 miles (70% highway, 30% city) - drove 20 miles after light came on
tank #2: 160 miles (50% highway, 50% city) - drove 15 miles after light came on

--- installed k&n air filter, royal purple 5w30 motor oil, msp16 flash ---

tank #1: 255 miles (70% highway, 30% city) - drove 20 miles after light came on
tank #2: will know at the end of the week!

so i've been hovering in the 16-17mpg area.. sucks :(

I think the six-speed automatic in my RX-8 is the reason my car gives more miles per gallon than most RX-8s - it is programmed for fuel economy over performance. I see this every day when I drive in auto mode and the tranny goes into 6th gear at less than 45 mph with a light load. At 60 mph, the revs are right at 2K which means a downshift with any push on the loud pedal, but also low rpms gives greater fuel economy while at a steady cruise speed.

My commute is 26 miles: 11 miles in the suburbs with eight stops, average, and 15 on urban highways that are usually moving bumper-to-bumper. The highway miles are usually in a lower gear, like 35 mph in third, then 40 in fourth, then back to 20 in second, then maybe back up to 45 in fifth, etc. Not really a highway cruise, more like constantly up and down through the gears while the traffic density and speeds vary. I do all this in manumatic mode, of course.

So my mpg has been averaging 24 or almost since I bought the car new last December. I run 15W-50 Mobil 1 (I like the additives) and 8 oz of MMO every 10-12 gallons. We'll see what the high summer temps bring, but so far I'm more than satisfied with my RX-8 fuel economy.

Was keeping track since I got my reman engine, but just lost interest this week heh. This is what I've gotten over 5.5 months and 6k miles; came out to 15-16mpg for 70c/30h.

When I bought my 04 manual 6 months ago I was getting avg 16 mpg and 200-240 miles per tank using premium gas at random stations . Last month I switched to exclusivly Shell premium and took my 8 across the state, I took a detour to hit a 15 mile stretch of road along a river and pushed it (really hard) the whole way. On the way home I got 21.6 mpg and well over 300 miles to the tank for the first time ever. I thought it wouldn't last and was just cause it was all highway but I have been getting 20+ mpg ever since I got back driving the same roads and style as before.

Take what you want from that story but my recommendations are Shell premium and a good stretch of hard driving once in a while.

I average 16-19 mpg in town...now I have come to find out that I get better gas mileage on the highway running 80 mph than I do going 70. At 70 mph on long trips I average 22-23 mpg, now at 80 I usually can pull out 25+ mpg. I did manage 341 miles out of one tank on my last trip to Mid-Ohio. Also, I haven't checked any AFR numbers but I think the engine leans out just enough at 80 mph to increase my mpg's.

With just over 126,000 miles my overall average is 21.1 MPG. Since changing the coils, wires and plugs, that's now grown to above 22 MPG (that consists of 18,000 miles). The only issue I have with the car is over the last 10,000 miles it is difficult to start when hot. I pulled the plugs today to examine them (replaced in Feb 08) and noticed one of the insulators was cracked. New plugs on order.

Thanksgiving day drive To/From Houston (about 280 miles from where I live) gave me 23.98 MPG.

figured that i would add my input here... I fill shell 89 or 91 only.

Mixed driving city/freeway, easy/hard and I have seen between 14.5-18 mpg. This is with a stock 06 GT. Most of my commute is freeway to and from school. I usually hit it on the onramp. I tend to average 1 mpg better with 89.

Annual update after five years for 2004 Grand Touring MT purchased 60 months ago:


Purchased 1,912 gallons of Shell 93 exclusively
Average price paid: $2.66 a gallon
Total fuel cost: $5,083
Total mpg 20.4
Fuel cost per mile 13.1 cents
488 gallons per 10,000 miles


Cheers,
Oranje

Thanks for sharing. Averaging 18 mpg now with the winter gas mix. I plan to add an exhaust next year to see if that improves any.

I got 8 miles a gallon for two or three tanks of gas. I was forced to use 92 octane BP in a very hilly area in winter. Besides that, I have averaged 14-15 mpg :(. 2004 AT with around 21,200 miles

Ethanol free fuel better for engine? Better mileage?

15.5

50-50 highway, but fast as hell and never let it drop below 3K RPM. I also engine brake, a lot. What the hell, the car is not much fun short shifting at 2K. If I wanted good gas mileage I would have bought a Miata.

15-16, Haven't seen mazda since 07 I prolly need an ecu flash. but if I don't hit 8k im not happy.

what?

what?

I don't trust the dealership anymore. They tried to convince me I needed new brake pads after 11k, I checked them they had ALOT left, enough to get me too 42k. Tried to get me to buy new tires at 11k as well, they had plenty of tread left, not even close to the bars (if I remember correctly 8/32nds when i measured). Took it to them again at 15k and I of course needed tires again, came out with the all the tires worn on the tread bars (which doesnt make sense to me, unless the swaped them) I bought the tires and havent been back since ($1200). I wouldnt have bought them if it wasn't snowing and I had to be to workin in 2 hours. This doesn't include several other sketchy things. I just do all my own stuff now... Nothing really else left for me to do.

I have a little over 37,000 miles on mine and I'm not sure what's happened in the past couple of months. It's almost like my engine had a 32,000 mile break in period.

I used to be happy if I could get 17 mpg on an all highway, no A/C trip. I just went to Kentucky and back with the A/C on ALL the time and I did just over 22 mpg! What?

Also, based on a previous post in this thread, I've been trying to shift as close to 2,000 as possible. That's helped the local mileage tremendously.

Christopher

Just ran the numbers on my mileage since I bought the car at ~50k miles. Is it just me, or is the trend compellingly linear if we ignore the large spike caused by an entire tank of out-of-the-ordinary cruise control driving @70 (usual is mostly city)? I replaced my plugs just after the first data point, seems to have had no effect.

By my calculations using a linear fit, I should hit 0 MPG on Jan. 20, 2011 :crazy:
All's good, though. If I wait another year, I'll be GENERATING a gallon of gas every 10 miles! This renny is gonna make me rich :naughty:

Seriously, though, anyone have some insight as to what may be causing this? It seems (to me) that this downward trend in MPG over time is common in at least SOME '8s. I will be installing BHR ignition around Christmas, so we may be able to see something interesting. My coils are likely the originals. Gonna pull my plugs when I install the BHR kit to see if my old coils have messed 'em up.

Progman32, your car sounds like it needs some basic TLC maintenance. Coils, plugs, and airfilter will likely return the 16 city/20 highway numbers.

hey guys, i just bought my 05' rx8 (45k Miles) about 2 months ago. I have been getting 10-12 miles per gallon average from city driving. I usually cruise anywhere between 4000-7000 rpms because, to my understanding, its better for the engine. I'm unaware about the mazda flash update or what not and i'm wondering if it costs anything or if its a free update? Will it even help that much? I'm getting my car proffessionally tuned next week after I get my exhaust and CAI installed. will that make a difference either? Thanks in advance.

I have an '04 MT with close to 80K. I get ~17MPG city. Make sure your air filter is clean, oil checked ever ~500mi. Coils (known to go bad) will cause poor gas mileage as will dirty plugs. I recommend using premix (4-8 oz. 2 stroke oil) in the gas tank every fill-up.

I have not calculated my mileage yet, but mine is pretty bad.

Just changed the plugs and coils, wires will be here this week. Oil change and new filters.

So far I have gone about 70 miles on half tank. Yay. Looks like I need to start driving my Grand Cherokee again.

I've been calculating my MPG every time I fill up since I bought my car new in 04, currently about 92K miles on it.

My overall average is 19.17. See the chart for month to month and trending data.
(The dip in December 08 is not correct.)

The biggest tip I could give is to fill up your tank consistently meaning let the light come on and fill up until the pump shuts off. Filling up the same amount, or close to it, will result in better calculations of MPG.

for some reason i got 26mpg driving up to Plano this past weekend
that was my 1st long trip in my car

city mpg is around 16mpg

My 2004 6-spd is only averaging a very consistent 13.5 mpg for city/highway driving. As you can imagine, I am not thrilled about it.

Could new spark plugs, coils and wires plus a new air filter (old one is old but not too dirty) improve these numbers?

Thanks!

My 2004 6-spd is only averaging a very consistent 13.5 mpg for city/highway driving. As you can imagine, I am not thrilled about it.

Could new spark plugs, coils and wires plus a new air filter (old one is old but not too dirty) improve these numbers?

Thanks!

How many miles are on these maintenance items? I wouldn't let any of them go more than 30,000 miles, or less depending on your driving habits and conditions.

How many miles are on these maintenance items? I wouldn't let any of them go more than 30,000 miles, or less depending on your driving habits and conditions.

I just got the car with 73k miles, and I'm not sure if or when the plugs/coils etc have ever been changed. I believe the oil was changed regularly, the car is now driven conservatively. I'm hoping the coils/plugs/wires make an improvement. Any DIY threads here with pics? I have the technical manual.

Thank you!

Hey guys! I just got an Rx-8 a couple of days ago. I considered the mpg i was gonna get by getting this car, but now im considering just riding the bus to work b/c this car is gonna leave on the street if i keep going like this. well i read about the m flash for this car. So where do i get it? how do i know if the car has it already? bc i haven't calculated my mpg yet? but it's pretty bad!!!
It's an Blue '04, Grand Touring Automatic. 50000 miles on it.

I will sincerely apreciate Your help!!!

My 2004@80K still averages about 18mpg combined city/highway. I wish it was higher but the motorcycles offset it ; )

I am getting around 15mpg (take into account that I just bought the car two weeks ago and am driving it a bit more aggressively than I will on down the road) I read something earlier about the "M flash". Is that something a mazda dealer would do for the car? Anybody recommend doing this? Thanks

Just read lions post about 2 up lol... I'm in the same boat as you dude.

I have discovered the secret to great gas mileage for our cars. No need to thank me. :ylsuper:

43k miles and getting 20mpg consistently while still getting on it at least 5 times per trip.. mostly city miles too.. weird huh?

Hey guys,

I changed the spark plugs, coils, wires and air filter. Oil has been maintained properly, the car is driven on shortish trips often up and down a mountain, and I'd say the mileage has improved from an average 12.9mpg to 13.6. Hot/cool engine cycle trip length is about 10 miles, which I know is not ideal for fuel efficiency of any car, especially that of a rotary that takes about 10 miles to get hot. The best ever mileage was done cruising in 6th over a long distance and retrieved 19mpg, but this was before the maintenance.

As you can probably tell, I'm not thrilled with an improvement of just .7mpg for my average driving needs. I've seen people mention an "ecu flash" but is that real or is it some voodoo that just echos in the forums and means nothing. If anyone has any ideas or recommendations, please, I'm all ears. Otherwise I may be selling the car.

Thanks!

Different thought. I did all the maintenance and cleanup stuff in the First $100. I also did Plugs and Coils, got me from averaging around 19 to averaging around 20. Maybe 60% Highway, 40% City, flat roads, Florida. I made one recent change, and got an instant 10% increase (holding steady after 4 tanks). I swapped the stock springs for H-Tech (about an inch in the front, maybe .25 in the back). The lower front make the car look better, and the MPG went up instantly. I did the math today, springs will pay for themselves inside a year in gas savings. I have no idea if lower springs would have done more. That is for someone else to try.

Hi my name is Cole I have a 2005 rx-8 with 60,000 miles that is only getting about 8 mpg ecu has updated flash and have no code has any one had problem like this? Please help

Cole, I would recommend changing the air filter, the coils and the plugs. The stock coils last around 60K then they start weakening. Get your cat checked, if it is clogged it will kill your mpg. The cars on average get between 15~22 mpg, some better some worse. I get around 18mpg and I drive aggressively. At least once a day you should redline the car, these motors do not like carbon buildup.

Swiftnet thank you I did take it to the dealership and they said that they checked the coilsand that they where good. They told me a tune up would be good so changed the plugs out which it grab tpms a little quicker, and installed a knn air filter which the gas mpg got worst after I put that filter in? And everyonce in awile I get a really bad rotten egg smell in side the car?

Rotten egg smell is the cat. At 60K it should not stink. My cat died at around 65K, it fell apart and sounded like rocks in my exhaust.
You gotta be careful when choosing a Mazda Tech. I tried three different Mazda dealerships for maintenance until I got really frustrated at the poor outcomes. I contacted Mazda US HQ and they recommended I take the car to Tyrone Square Mazda, which was a 90 mile drive. That is the only dealership I will let touch my RX8. All the others were clueless. Whenever I need deeper maintenance on the 8, I take a 180 mile round trip drive. To give some perspective, I have three Mazda dealerships within 50 miles (15/20/45) and they all are technically challenged when it comes to the RX8.
Was your K&N filter a drop in replacement or does it bypass the OEM airbox?

The kn&n was a drop in

The K&N will allow a little better airflow, so MPG should not drop. A clogged cat will absolutely kill mpg. I'd get the cat checked out. I highly recommend finding the Mazda service center with the best rating. Have them check your cat.

Nubbie here, Just bought an 04 and the mpg suck i was on the highway and was able to watch my gauge just slow drop i only went bout 20 miles and burnt damn near just ova a 1/4 tank

Check the threads in my sig. I would start with the first $100 stuff. If you provide data on car, miles, maintenance, stuff like that, people can help. After the $100 stuff, you can worry about other stuff.

Welcome to the club.

Rjayx-8, there's no way your 8 is running normal. Yes, they get bad gas mileage but no where near that bad. You should have your 8 looked at or try some of the tips a few of the guys like to offer.

Flash

First im going to look in to the flash, I work at a dealer as a Hyundai tech and we have a mazda dealer...imma get one of our mazda techs to check it out wit me and do the reflash first...I also have a CAI coming so that should help lean it out a bit and while im installin the intake i'll clean the MAFS.thanks I knew something ain't right wit but i'll get it fixed thanx man.

alright me and the mazda tech checked out my 8 and we found there is a intermit. misfire, so i'm just going to hit up rotaryfx and get plugs and wires from there the ignition coils are the same as factory so I get employee discount on parts and I'll just get those form work. Start with that first.

I am new to these threads so please don't shoot me for asking for help. I have owned 3 RX7 and NEVER gotten as poor MPG as I do on my 04 Rx8. I drive a mix between city and hwy and I don't hit the accelerator much, yet the best MPG I can seem to get all around is 15.6. Most of my drive to work is though the country long roads not many stops then I hit the beltway (opposite of traffic). I drive at about 65-70mph in 6th gear (speed limit is 65). I do run the motor to read line as told by other at least once a week. I also use 93 oct (only) and let my car warm up before driving.

I have recently changed my Spark plugs, Wires and Coils. I can not figure out why I am getting so poor MPG I was expecting 18-20, I only have 58,xxx miles on my car. Any help would be welcome. I have scheduled a "Stealership" appointment as I can not seem to figure out what is going on. I fill up at 11.9 gallons and I only get around 174-180 miles 14.9-15(MPG) the most I've gotten out of a tank is 220. Please help as I know this is far from normal. Someone else suggested my Cat is bad yet I don't notice any poor acceleration.

when u take it to the dealer have them check for ecu/pcm updates i work at a hyundai dealer that has a mazda side and me and one of the mazda techs went through the same steps changing the coils, wires and plugs which did help out some but there was an update that had not been done, after we did the update my mpg went up

Hi I'm going.g to delete my other thread as soon as possible but I bought an 04 rx8.. Auto. . It got terrible mpg and then engine died so I just got it back after waiting three months in the dealer ship expecting 18-20ish.. And here I'm getting 12-14 city and 14-15 highway.. And yes I'm doing my calculations correctly by filling it up then another pump or two driving till empty then calculating... Wires spark plugs and coils engine core was all replaced techs said it has n flash... And the cat is fine.. No glowing or rotten egg smell... Have tried every variance of driving style with no improvements.. I thought it maybe be fuel filter.. But they apparently have a long warranty.. Or injecters. .? Fuel injecters cleaner??? Anyway any help is greatly appreciated.. Car starts right up and runs absolutely great.. Just horrid mpg. ..

I have a question i get around 245 for 14 gallons on 93 oct its been that way since i bought the car i am assuming this is horribly low??? My question is if i take it in to mazda and it didnt have the flashes would they do them for free?

245 is pretty good if you're doing city driving. highway mileage should be much closer to 300, if not a little over.

I get 200 per tankful going to and from work 20 miles each way, primarily back roads.

If you don't already have MSP16 then your 8 has been off the radar for the past 4 years. There's been nothing new since then.

I drive back country roads which are mostly straight line i stop twice i drive 35 miles back and fourth from work so that 245 miles per tank is mostly highway miles. This past weekend i took a road trip which was 280 miles away. I had to fill up when i arrived at my destination and when I arrived home when i filled up both times it was 15.78 gallons so 17.78 pure highway driving with cruise set at 80mph

Okay I have a 05 gt 6spd, with 100,000km, and 10000km on a "new" mazda warranty replaced engine. with the new motor i have replaced/serviced the following, plugs, wires, coils, air filter, oil, coolant, transmission fluid, diff fluid, tires etc.. With this engine I have averaged 28L/100km or 8.4mpg!! The "M" flash was supposedly done when the new engine was installed. Once on a long slow highway trip I got 408km/253miles to the tank, but only once. I drive about a 50/50 split city hwy, the only mods are intake,catless midpipe, and catback. anyone have any clue why my 8 is so thirsty?

18 to 21 mpg 2006 Shinka, Ebay exhaust on country roads. City 16 to 18 mpg. I drive quite aggressively

My gas mileage actually got worse, I cant figure out what is causing it either.

Just got new engine from Mazda. Warranty had 5 days left. I get about 320 miles driving highway through tn, and 200 driving it like I stole it. Just got a blue voodoo shift knob, just one more excuse to drive it.