Hello I have had my RX8 for under a month and I've been getting around 200miles for a full tank of premium gas. That's only 16mpg!!!!! I barely drive it hard, try to keep it under 3000rpm and never to exceed 4000rpm. I hear the manual guys getting around 18-20mpg. Arn't we suppose to be getting more mpg than the MT guys? :dunno:

:wink2: A well driven MT will always have a better gas mileage as an MT!
You have slip in the transmission and the transmission is harder to move and cost power and therefore gasoline! That’s the reason why AT cars are also not as fast as an MT. In the RX8 is also another problem present. It has only 4 gears! A bit more torque cannot fix the problem.

Hmm you have a good point but on the specs sheet, it says AT has a higher gas milage. I'm just wondering what other AT drivers are getting and what I should be getting.

Another thing is.. Most cars fall in the EPA range of mpg. However, I am no where near 18-25mpg.

:wink2: A well driven MT will always have a better gas mileage as an MT!
You have slip in the transmission and the transmission is harder to move and cost power and therefore gasoline! That’s the reason why AT cars are also not as fast as an MT. In the RX8 is also another problem present. It has only 4 gears! A bit more torque cannot fix the problem.

Not true in this case. (And for some cars the ATs are just as fast as the MTs, mostly high torque V8s)

The 8's AT is geared much higher than the MT. Cruising at 80mph in the 6spd puts you at almost 4000rpm, while the 4AT puts you at 3300rpm. I get 18-20mpg city, 23-27 highway depending on speed.

Your gas mileage depends heavily on cruising rpm. Transient rpm means little, as you only rev high on acceleration. Slip only occurs on acceleration. The transmission goes into lockup at cruise, meaning it's directly coupled to the engine. Keep an eye on your cruising rpm and gear. I'm willing to bet your using 2nd and 3rd gears alot more than you have to. 95% of your driving will be done at cruising speed.

And rev that engine. You need a redline every now and then to keep carbon from building up. Carbon buildup will be detrimental to power and mileage. I redline multiple times a day, but in traffic I get to 4th gear as soon as possible. Try reseting your ecu (there's a thread in the tech forum), and changing your driving habits to using one gear higher than you usually do for certain situations. I'd put money on better mileage.

Lots of idling and short trips when the engine is cold will cause lower mileage as well. The car burns alot of fuel when cold.

My car is only at around 600miles so I dont think I would need to clear the carbon. And no I drop to 4th gear at around 40 mph, my car pretty much skips 2nd gear. I'll change gas and see what happens. I will switch from premium costco gas to maybe 89 shell gas.

I'm getting around 13.8 mpg driving in city traffic w/AC on... I got stuck in mad traffic one day for about 2hrs... got 10.2 mpg on that tank, so your doing better than me...

14.9 MPG give or take, 90% city driving, I pretty much have never gone over 15 since getting the car a year ago. I drive 100% in the manual shift mode, rarely ever use 4th gear because anything below 50MPH and the car starts bucking like a bronco (likewise with 3rd, anything below 35 and the car feels like it's going to die a horrible death). But ever since hearing about the carbon build up problem, I have been doing a lot more 5k RPM runs in 1st and 2nd whenever I can, which probably ain't helping the MPG. But whatever, I wasn't expecting great MPG when I bought the car, as long as I don't drop below 13, I'm happy.

I drive 100% in the manual shift mode, rarely ever use 4th gear because anything below 50MPH and the car starts bucking like a bronco (likewise with 3rd, anything below 35 and the car feels like it's going to die a horrible death).


That just sounds ridiculous. I use 4th down to 21mph with no problems. Sure you can't accelerate much, but that's what the shifter is for. But hey it's your mpg. Use 4th to cruise and not to accelerate. Though mine accelerates just fine in 4th at 50mph in traffic. Either you're exagerating or there's issues with your car.

My car is only at around 600miles so I dont think I would need to clear the carbon. And no I drop to 4th gear at around 40 mph, my car pretty much skips 2nd gear. I'll change gas and see what happens. I will switch from premium costco gas to maybe 89 shell gas.


Let's say you're driving 30mph for some reason, what gear are you using? I use 4th.

I am getting 21-22 mpg with my A/T

I have an MT and get 21-23 MPG, Country road driving. I never run UNDER 3,000 rpm's, shift around 5,000 -6,000 rpm's in lower gears and while cruising in higher gears I downshift to stay above 3,000 rpm's. Going up the mountaian I cross I keep it around 4,000-4500 rpm's. The Rotary is bogged down under 3,000 rpm's the only time running at that low of rpm is practical is while going downhill. The best gas mielage is obtained when we are using the gear that will maintain the desired speed with the gas pedal depressed the least. I use 87 Octane Shell.

That just sounds ridiculous. I use 4th down to 21mph with no problems. Sure you can't accelerate much, but that's what the shifter is for. But hey it's your mpg. Use 4th to cruise and not to accelerate. Though mine accelerates just fine in 4th at 50mph in traffic. Either you're exagerating or there's issues with your car.


Nope, not exaggerating at all. The car lugs horribly at those speed/rpm combos I mentioned. I'm not the only one with this problem either. I've asked about it in the past and some have attributed it to the rotary's lack of low end torque, but nobody ever gave me a solid, definite reason as to why I might be getting such lugging in an automatic. Last time I mentioned it to the dealer all they told me was "oh it's probably in too high of a gear".

That shouldn't be happening. Mine cruises fine in 4th down to about 25 MPH. Like therm8, if I need to accelerate from low speed, I'll downshift (I typically drive in Manual Mode). But I've NEVER felt the engine lugging like an MT car in too high a gear.

I get an average of 260 miles per tank.

I am getting 21-22 mpg with my A/T

Hmm.. when did you buy your 8 and what was the production date? (Same question goes to all AT drivers who have around 20mpg)

And yes normally if cruising at 30mph I'm at 4th.

I read in the owner's manual that you're only supposed to use 87 octane...is that true? Or does premium gas give it a little more oomph? It says that maximum performance comes from regular, but that just doesn't make much sense to me...anyone have any insight into this? :wtf:

um you should read that page a little closer=) because mine says 91 octane is best for it. performance wise.

Hmm.. when did you buy your 8 and what was the production date? (Same question goes to all AT drivers who have around 20mpg)

And yes normally if cruising at 30mph I'm at 4th.


built Jun '03 purchase Nov '03, currently 48000 miles. still on L flash. Perhaps your just getting break-in mileage, though I've always had relatively good economy. Do you do alot of idling at stoplights? Short trips?

My bad, you are absolutely right, 91 octane is the recommended fuel...haha I'm stupid, I thought I read "regular unleaded" for some reason...sorry about that :wallbash:

My bad, you are absolutely right, 91 octane is the recommended fuel...haha I'm stupid, I thought I read "regular unleaded" for some reason...sorry about that :wallbash:


Do a search on octane ratings and the effects on the 8.

Well yes my trips are considerably short, however how might that have an impact on fuel economy? Break-in mileage is what I was thinking. (Friction in engine during break-in uses more fuel.. right??)

Well yes my trips are considerably short, however how might that have an impact on fuel economy? Break-in mileage is what I was thinking. (Friction in engine during break-in uses more fuel.. right??)

Well, the car burns considerably more fuel during its warmup than at any other time. If a majority of your driving time is spent in this warmup period, then your average will be lower. This is probably the culprit. You could see some improvement with some more miles on the car.

hmmm maybe a gas saver would be to let the car warm up before driving its worth a shot!

Mine is an 04 AT with 7000 miles.
91 Octane with a 200:1 pre-mix,
60 second morning warm-up's,
90% City under 40mph (mostly in 2nd gear)
10 minutes from work.

My "wonderful MPG = ???


Never more then 12 MPG...


I'd love to get your "bad mpg" :)


Did I mention I have a Silver 8 ?
(?Curse?)

Not true in this case. (And for some cars (http:///#) the ATs are just as fast as the MTs, mostly high torque (http:///#) V8s)

And AT 6CYL Supras ;)

I have an April 04 build date and have 21500 miles on it now. I get about 19-22 mpg mixed driving. Best I ever had was 27 that was pure highway driving with the A/C on. I use 91-93 octane, whichever is at the pump.

90% City under 40mph (mostly in 2nd gear)


Well, there you go :wallbash:

Well just for informational purposes my build date is June 2005. Well lets see my mom's lexus is rated at 19/27 she averages 20-21. I'm rated 18/24 and I recieve 15-16.. I suppose that works out ok/ :dunno:

Mine is an 04 AT with 7000 miles.
91 Octane with a 200:1 pre-mix,
60 second morning warm-up's,
90% City under 40mph (mostly in 2nd gear)
10 minutes from work.
My "wonderful MPG = ???
Never more then 12 MPG...
I'd love to get your "bad mpg" :)
Did I mention I have a Silver 8 ?
(?Curse?)

No, its no curse.... JUST GET OUT OF 2ND GEAR!!!


:wallbash:

you must be over 3k rpms the entire drive over...

seriously, get out of second.

No doupt that you will get the best gas mileage out of your car by shifting at the right time (up or down) in order to keep the engine as much as possible in the rpm range where it has its highest torque and at the same time pressing the accelerator as less as possible (for example, rather shift down, than to press the gas pedal down to keep the speed at a hill) ! Use always gasoline with highest Oktan number in order to avoid knocking and therefore your control unit to go to retard your ignition timing. Have the right tire pressure and not unnecessary load on board, keep the air cleaner and sparkplugs in good shape, and avoid short trips! Best gas mileage will be at the highway in warm engine condition, straight lane, no hills, pedal movement next to zero, at 4. gear in best torque rage till the tank is empty. What ever comes out of that test, you can never reach a better result, since all other conditions are worse. An almost new engine has a higher gas mileage, cost by lower compression and high friction. An very old engine (well driven before) with still good compression has a better gas mileage (but most of the time the compression is not as good as before anymore). Wider tires have more friction and nor air resistance, sometimes you change also the diameter and therefore the length or the ratio. That results also in different rpm at certain speed and can cost more gas (depending on the speed range you drive). At acceleration always more fuel consumption! The car driven in very hot regions or during noon will also use more fuel than the same car driven at 3am or in a region with lower outside temperature. While you start the car in (engine!) cold condition, am hot area is better, since it doesn’t need too long to head (runs lees time in richer mixture)!

I forgot:
lights off, A/C off, additional saound systems off, no wide or fast turns with the power steering...
That all can lower the fuel consumption too!!

I forgot:
lights off, A/C off, additional sound systems off, no wide or fast turns with the power steering...
That all can lower the fuel consumption too!!

No, its no curse.... JUST GET OUT OF 2ND GEAR!!!

you must be over 3k rpms the entire drive over...

seriously, get out of second.

Thanks for the advice.... looks like I'll be driving in 1st gear from now on if I want to exceed 3K... :crazy:

I think he meant:
"Wow.. you must be over 3000 rpm the WHOLE WAY!!! (bad)"

The best MPG i got was 26mpg (canadian gallon)

I think he meant:
"Wow.. you must be over 3000 rpm the WHOLE WAY!!! (bad)"


thats what I meant.


at 40mph im usually at 1.5-2k rpms.

and thats in 4th.

I don't know how you can stay in 2nd the entire drive.

Something seriously need done about this.... i'm getting 15.2 mpg........ I mean WTF thats not even close to 18-25 And i'm 50% hwy 50% city..... I should be around 20-21.... guess time to complain to the mazda corp... yay...

Mazda won't do a thing for you. EPA tests are performed under controlled circumstances that are the same for every car. They do not, however, coincide with everyday driving all that well. Mazda will just blame your driving style. I would analyze your driving habits and driving conditions (short trips, stop and go, etc) first, as most likely that's costing you a couple mpg. A good ecu reset prior to changing any habits will help the car change habits as well. Make sure all maintenance is up to date and clear out any carbon buildup, check tire pressures, empty all the crap out of your car (I was carrying nearly 100lbs of stuff I didn't need to be carrying), etc. There's lots of things that can affect mpg.

I get around 15mpg on mine

Heh, I'm getting anywhere from 8-10mpg. very short trips, not much warmup or i'll be late to work :).

I'm getting 17.5-18 driving hard in town. Guess I ought to be thankful!

I have an 91 automatic RX-7. What I don't quite grasp yet is the fact it gets better gas mileage with the same type driving style compared to the 8. I don't want to hear about how they richened it up for the cat's mandated warranty but would rather have some proof of the A/F ratios for an auto at cruise, etc. I thought the renesis was supposed to be able to run leaner due to the side port configuration compared to the old 13b in the 7's.

Disappointed in the fuel economy of the 8, yeah, but damn it's a nice car overall.

Tim

i'm not sure what i get on mine cause i'm only 17 and i really don't care but i feel the pain. it takes about $45 of premium gas at $2.99 per gallon price. i drive about 1000 miles per month so the tank lasts me only for like 3 days and 4 days if i'm lucky. i just wish they had made the 8 with better gas mileage. i RARELY use the a/c. but i HATE to see the needle go down when i'm stuck in traffic. it just pisses me off. seeing my money go like that.