Vertigo 8

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!

mcsetech

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.

hemachayart

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 ).

VOODOO8

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/

Mendossa

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.

drgray

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...

zoom44

what gear what speed?

zoom44

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

Mendossa

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.

93rdcurrent

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.

Rockin302

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.

RX8Maine

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?

MPG > HP

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.

Rotator

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.

axsym911

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.

sosonic

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.

93rdcurrent

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.

ken-x8

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

DrDiaboloco

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.

DrDiaboloco

Oh, come ON....

sosonic

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.

RX8PDX

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.

93rdcurrent

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.

DrDiaboloco

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.

kellybrf

iTrader: (2)

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