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

 

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

 

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

If you are driving...

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

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

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

 

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

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

Is that about right?

Hunter

 

no you were feeling the secondary and tertiary intake ports opening

 

oh
sorry :o
you're right

ports, not injectors

 

^^good work on the girl

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

 

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

 

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

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

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

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

 

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

 

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

 

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

 

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

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

Want fuel economy? Get a TDI.

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

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

Support the WAR.. Buy more friggin GAS!

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

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

 

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

 

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

 

Just got back from a 1276 mile road trip.

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

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

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

 

Based on this:

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

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

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

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

 

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

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

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

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

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

 

Don't know if anyone mentioned this link yet:

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

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

 

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

 

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

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

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

 

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