Greetings all,

I now have about 2100 miles on the RX8, and followed break-in procedures pretty closely (in spirit at least). My mileage has been as low as 13.9, and as high as 16.0. My driving is around the suburbs and some medium sized streets, not too much highway - no more than 10% or so. My driving style is fairly spirited, and I do wind the car up. This last weekend I drove from Cincinnati to Cleveland and back. The tank on the way up (80% highway) got me 18MPG! This was averaging 75MPH, with a few miles at > 100MPH. On the way back I strictly obeyed the speed limit, and got 23.5MPG! Ambient temperature was 35-45 degrees, with a cross wind.

Consequently I am much happier about my mileage. At least there doesn't appear to be anything grossly wrong with the engine. Hopefully canzoomer's efforts will help in this area too.

 

i noticed my mileage got better on the highway too only problem is i dont do much highway driving and my work commute is all city.

 

Glad to hear the mileage improves. I am on my 3rd tank and getting around 14.5 mi/gal in the city. Had I not been reading this forum for the past month I would have been seriously pestering my Mazda service manager. With this vehicle weighing only 3K lbs and assuming a clean burn with low emissions it does make one wonder where all the energy goes. CanZoomer's ECU mod will definitely be in my future.

Thanks to all the fine folks on this forum I knew about the horsepower / mileage issues long before purchasing so I am most definitely not complaining.

 

Has anyone yet "tickled-out" the parameters for optimum fuel efficiency on these things? I know that in my decrepit Miata I can get as much as 39.9 (!) MPG by running a hair short of full throttle up to a bit less than 4,000 RPM. At WOT or over 4,000 it runs open-loop and mileage goes to hell (30 or less -- sorry).

I'm sure that there's a lot more to it on a befuddlingly complex 8.

{{{{

 

It seems like the car is really sensitive to idling at stop lights. City driving really appears to kill it! I don't really care, so long as I pass emissions testing and get semi-decent long distance cruising. I don't drive highway much. It's actually just as well, because I cannot drive this car too slowly. It's really torture running at 58MPH.

 

it gets real thirsty at startup and idle.

 

Heat!

I'm encouraged that someone has got 23.5 mpg, even if it was at a constant 55 mph. At least it proves that it is theoretically possible to get into the high twenties (UK mpg) although I can't see myself doing it very often.

 

I have been getting 16 MPG since I got my car but this week I hit 19 MPG due to mostly highway driving.

I usually fill up when the warning light comes on but tried going further yesterday. The needle soon went below E whcih got me concerned, I exited the freeway to fill up and there was 2.2 gallons left (full tank is 15.9 and it took 13.7 gal.).

I figure you have around 2.5-3.0 gallons left when the light comes on.