I have 6 gears, and as the RX-8 is geared so high, I actually added about 5 mpg by shifting 1-2-4-6, and maintaining 3,500 or less rpm. Shifting 1-2 to get rolling, up to about 30 mph, then 4 up to 3,000-ish rpm, then to 6th. Never once am I lugging the engine, I shift less, reduce clutch wear, and hardly ever downshift, since the rotary isn't much at lower rpm anyway. (got more brakes than clutch surface!)

Want to save even more is stick to regular 87 octane, it doesn't ping (which is the only reason I can find to run Super (what we used to call high-test)), and unless you're going to run on a track, the extra 5's not going to help anyway.

Enjoy

 

amazing.

 

yeah but doesnt the car run better with 93 octane.. and not to use 87 due to detonation considering i live in florida...

 

you should always use 91+ every other fill-up if you're going that route. IMHO anything less than what the manufacturer recommends is just irresponsible. But good idea on the shifting... it should save a few pennies every fill-up

 

The car is tuned for 91+ octane gas from the factory...sure you might get away with 89 but is the few cents of savings worth risking your motor?

 

Just say to 87 octane.

 

for me to poop on..

i run 87, always have.. but shifting like you say is not going to change a thing.. unless you are comparing it to a redline in each gear before you hit the speed limit..

beers

 

Keep in mind that every situation is a little different. I have used 87 octane since buying the car three years ago. No pinging, detonation, rough idle etc. Some cars seem more sensitive to octane rating than others, luckily mine runs great on 87.

I have done some short lived (5-6 tank fills) with higher octane at the same station (Valero) and got worse mileage (21-22mpg vs. 18-19mpg).

 

just dont look at the gas gauge, its better that way, im telling you

but sure u can run 87, everyones read the owners manual right? it clearly says it in the owners manual that u can run 87 but u will experience a lack of performance. idk i like my 8's performance so i dont want it lacking that much

i spend the extra 3 dollars each tank and premix, but thats just me

 

I may not be an expert on rotary engines, but on a piston engine, a high compression engine is what requires premium. Correct me if I'm wrong here, but I think the 8 runs a 10.0:1 compression. A Honda Accord 4 and 6 runs a 10.5:1 compression (fact) and required gas is regular unleaded.

 

it also has to do with the conditions you drive the car in and how you plan on driving the car.

if you drive hard and in hot weather detonation will be a problem with a lower octane. Also, premature combustion on a rotary engine due to a lower octane will make the car run much worse. think about it in you head, if the air/fuel combusts due to the compression before the spark plug stroke how smooth is your rotary engine going to run? after all octane is a rating of how likely it is that the gas will not combust under compression without a spark

seems like less of a big deal in piston engines, so personally i wouldnt wanna risk it.

 

This was my first time writing, you guys are hilarious! "Just don't look at the gas gauge..." that's great! I know it doesn't or won't work for some, but these days, you gotta give it a shot. My car's not any worse for it, actually better (as well as using Mobil-One synth'), as I have as a side effect, reduced the RPM related stresses on the engine, so I think it balances out.
The gas-pings differ I find in talking to some of my refinery working friends who brew the stuff, is that not all 87's (or 92's for that matter) are equal. It no doubt will also depend on what additives are there too. I buy from no more than two named suppliers (Exxon/Shell) so I can better depend on consistency.
Have fun! Be safe!

 

ok so what happens when you lean the factory afr to 13's insted of 11's on 87 w/ ethanol?

 

i am one of the ones that almost always gets 20+ mpg. and have always run 87 except for track days..

suggestions to all.

stay out of the city. if you live in the city enjoy the car.. mpg will always be bad
shift at below 3700 rpm.
keep the car below 75 mph.

and at least one or two redlines a day.

buy good quality gas. i dont believe in the top tier stuff. i tend to use amaco.


92 k miles. only 5 tanks below 20 mpg.

beers

 

First of all, wow swoope, that's some amazing mpg over 92k miles.
I do basically all city driving. This car touches the interstate maybe once or twice a month if I'm lucky. I can expect around 16 mpg, 18 if I do really well. When I go on trips it typically creeps on up into 21 mpg territory.
I would assume that if I did all highway that would creep up even more since the ecu would learn that it needs to deal with mainly highway driving.

I change gears in different situations depending on my mood, and pretty often drive the car at an average of 4k rpm. I do most of shifting at 4k, but often forget to shift up to 5 and 6.
When I shift up and keep the car in a general 3000-3500 rpm range, that's when I notice an increase in mileage. I do believe that that makes the difference between 18 and 16 for me. So I think I agree somewhat with the OPs idea of low rpm shifting.

on the other hand you have people saying low rpms kill this engine with carbon build-up. So I wouldn't agree with the idae that this avoids "high rpm wear" at all. This car needs high rpms. So there's a balance between fuel economy and keeping the engine happy by revving it (and keeping me happy by madly revving it).

I guess since I fill up only once per month and the economy difference for me is so low, then I wouldn't benefit from 87? What do you guys think? Here we have 89 or 93, so I use 93. I read somewhere you could actually mix the tank half an half with 93/89 to get the needed 91 to save a few pennies.

 

can lead to detonation on hot days with lower octane - been there done that . Don't know about the ethanol though ....

 

Swoope, I get better mileage on the highway when traveling at least 80 mph...my last tank at 80 most of the way yielded me 27.2 mph on mid grade and premix.

 

I really really don't get how you guys get anything over 19mpg on the highway even.

The highest I've gotten on a 600 mile interstate trip with this car is 17mpg. I live in the city and commute on the highway. My tank is typically 150 miles highway, 50 miles city. I do 200-210 miles till the light is on for a good 15 miles, that is it. That works out to some 13mpg.. Consistently.

 

what size tires are you running or rear gear!!! you have some odd trick going on! wait this an ac off with a 30knot tail wind hipermilling?

really good for you! mine has just dropped off a bit.. have to do the plug look / 44k. track day fix.

btw, try the 87 oct. you might hit 30 mpg!

beers

 

karma is a bitch!!!!

next time you go on a trip. pull the room fuse..

and drive the car see what it gets. you would be surprised.

beers

 

hahahahahahhahahahhahahahaha.

holy **** cant stop laughing.

 

So theoretically I could run 85 octane and be just fine since I live in Colorado Springs at 6.5k feet??

 

HAHA! I'm running 275/35's all the way around, running stock gears,and have not done any secret tricks. Only thing I can think of is the fuel leans out just enough to make a difference. I really have no idea why my mileage is so good on the highway, but I'll take it! I do average 18-20 in town also.

 

MTBE or E10?

 

keep it under 3500, u'll be surprised.