Well I was able to break into the “range” that Mazda places on its window stickers for the RX-8. The “big” numbers you see with the automatic are 18 city, 25 highway. However the small print below it says the actual range can be 15 city, 28 highway.

Anyway, I have generally gotten 12-13 city. Poor, just poor.

So with my last tank I purposefully shifted at 3k through each gear (paddles). I drove 225 miles on the tank with 40 being highway miles.

Fuel economy? 16.19 mpg for this tank. I’m pleased but pissed. I personally feel that it should NOT take such granny driving to even be within the range of fuel economy. Hell I was getting rolled by everyone! I always had people looking at me with the look: “WTF? Why are you driving so slow?”

I dunno, I still think there’s something wrong with the ECU programming in my 8.

Anyway, this next tank I’m going to shift at 4k and see how my mileage changes.

BTW, I have about 6,000 miles on my 8. She was purchased the last week of Jan. 2004.

 

Hey 310...

Have you had the M-Flash upgrade? Also, what brand gas and grade are you using?

 

Yes on the M flash.

I'm running with 91 octane.

A while back I used 87 for two tanks. No change except for the "back firing" of the exhaust - it happened more with 87.

 

Just pretend the Renesis is a V8. My wife's car is a V8 and it gets crappy mpg in the city, less than what the EPA says. But we don't care, because we knew the V8 would suck gas when we bought the car. Same goes for the RX-8. Rotaries have never been known for getting good mpg. Enjoy the car.

 

I guess maybe I am lucky - I have an AT and have never....NEVER... ended up with less than 18 mpg. I use Shell V Power 93 Octane. I did a Memphis/Nashville (Opry Mills)/Memphis last weekend - All freeway driving except for about 8 miles. MPG was 24.3. With 50/50 city/freeway I average about 18.5.

I'm knocking on wood that my luck holds out.

 

o well wat is m flash guys? and.. i got a another question. if i install a supercharger in to my 8. will it get a better mpg. i mean will it drink less gas.

 

it will use up a lot less gas if your engine blows up.

I don't recommend being one of the first to supercharge it

 

Are you using the paddles?

I wouldn't mind my latest MPG if I was driving the way I would like to: shifting at 5-6k rpms but having to drive like granny and ONLY getting 16 mpg is pathetic.

 

Take off the K&N intake (pos anyway) and switch back to stock your poor mpg may be a result of faulty MAF readings.

 

I played with the paddles a few times at first. After that, haven't used them at all.

 

i really dont think M flash matters at all..... ive still been getting 13-15 mpg..... plain sucks

 

Have you checked your spark plugs recently??? Friend of mine was getting horrible gas milage in his 8... but one of his spark plugs wasn't firing at all.

 

Crappy mileage before the K&N... and crappy mileage after the K&N. No effect, no change...

 

Well, when I had the M flash some time ago, the dealership said they checked for any "tripped codes." I would *think* a faulty spark plug would trip a code. It's something to consider and look into. Thanks.

 

I seem to reply only to these MPG threads that pop up every few days or so, but I figured I might as well post again...

70 HIGHWAY / 30 CITY I get about 18-20 shifting at around 4.5kRPM.

-Rupes

 

You mean "pretend it's a V8 but without torque".


Sure, that makes it better.

 

no, more like, pretend it's a v8 and can continue to make more power as it goes over 4k rpms

 

I think sometimes we are all just too obsessed with mpg. I say to hell with it, it's a rotary, and drive how I want to drive (which means a lot of full throttle red line shifts.) Hence, when I get 14 mpg in the city, so be it. I've gotten around 17 city if I drive like a wimp, but that's no fun. I get really good mpg on the highway, but I drive about 80-90% in the city.

 

Can we please create a 'I didn't properly research the car before I bought it' forum? Or at least a 'newbie' forum?

 

Yes it's a Rotary it's not the piston engines we have been so use too. It's a design that is still in its infancy. Not very many millions by comparison are being spent on it . How many piston developers are there! When I bought my first rotary it had 100hp and at best got 12 mpg in town and 21 hwy. Now I have over 200hp and get 16 in town and 27+ hwy. It's come along way. The rotary has improved in every way. If you had an early rotary you know how much more torque it has, and now all the way to the redline. There is nothing like its Electric like engine. Thats why I keep coming back for another. It's just an Exciting Car, not that there are not many, many piston cars that are not more exciting. This one is a one of a kind and it's your kind. It's hard to keep your foot out of it, and it's good at keeping me out of trouble. I have thought more then once when I put my head on my pillow at night "I better take it easier". This car gives me so much confidence........

 

What's that supposed to mean junior? Am I supposed to assume the Renesis is the same as prior rotary engines?

I need the "know it all" members to PLEASE provide me with the "research" that says the Renesis engine will only get 13 mpg city even though the window sticker says it should get around 18?

Seriously, where is this "research" that says I should not believe what is represented to me and "assume" I will only get 13 mpg since that is "what rotary engines" get for mileage?

If you have nothing to contribute to this thread, why bother posting? Maybe we should start a "I'm a total troll and have nothing to contribute to threads" forum? You could be the moderator.

****, you probably don't even know what "Renesis" means... so I'm just wasting my time and server space by responding to your post...

 

6M with M-Flash
1,400 Miles
Best tank ever was 17.65 MPG. I've never even hit the "City" EPA estimate the entire time I've owned my 8.

Yes, I Zoom Zoom, and I just love the sound of the engine. Still it's disappointing not even hitting the EPA city rating.

Last tank was 16 MPG. My friend was commenting he gets 14 MPG in his Full sized Chevy 4x4 with a camper on it! That’s got to be 5000LBS with the aerodynamics of a brick.

I can only imagine what Rotaries would be like if they had received the same amount of R&D that was invested in piston engines during the last 20 years. Heck, I would settle with only 10%

I’m really curious what my mileage would be if my ECU had the original Mazda Lean air-fuel programming that Mazda initially hyped on the Renesis.



Also, will the 2005 8 have a different ECU fuel map then the current M-Flash?

 

eh, the gas mileage isn't that much worse for me than my wrx. I get about 18mpg consistently. Though when I auto-x it equals about 9mpg. I bought the car knowing that it wouldn't be too fuel efficient. doesn't bother me much.

Best mileage: 21mpg straight up hwy

I mainly use V-power, but that's only if I'm in the area of one- if not, it's whatever, the car doesn't seem to mind so far as I've noticed

 

310, the only suggestion I can give you is this. Try a couple of tanks of Shell V-Power and see what success you have. Don't "drive miss daisy" around either. Give it some welly and enjoy it. If the problem persists...then all I can say is..... love the car not the mpg.

Good luck.

- Irish