you can tell when the engine is running happy and when it thinks the gas is **** and is retarding the hell out of it.

 

try citgo 87.. my honda LOVES it.. the rx8 doesn't seem to mind either. I do find that the quality varies by gas station for some reason though.

 

It runs really good on Exxon, Chevron, etc. Almost any other gas is fine. For some reason it just doesn't like Shell. I can't explain it. Mileage noticably falls. Octane also doesn't affect it in the slightest.

 

Pinging is also affected by the intake temperature. On 87 octane a given engine might ping in the summer but runs fine at low temperatures in the winter.

If it doesn't ping lower octane is usually better since it has a higher energy content per mass of fuel and it will burn faster = slightly more power and slightly higher mileage.

 

Ya, you work for Shell.

 

I use Mobil(93), BP/Amoco(93), Citigo(93), Shell(93), Getty(92), Sunco(94 Ultra, Only if I go NJ), and some "no name brand" b4(92)

Mobil and Shell always gives me a better "feel" for some reason.

Theres no Shell station nearby, but mostly I use BP

Why ?

Cuz the gayass Mobil nearby almost always charging people like 10-20 cents more for every gallon (everygrade) when compared to the Brother BP thats like down 4 blocks. So I almost always go there.

Oh and yes I always use whatever highest Octance Rating. I tried BP's 87 Octance once, car wasnt as responive as b4, might have something to do with weather or whatever. or maybe just my "Feel". Ahh, but Im gonna stick with whatever the highest. Call me a Chicken :-( but I love my 8, and I wanna give it the best !

 

I believe shell uses a 10% ethanol mix in california, this is a pretty good thing since the ethanol prevents detonation, makes the fuel cheaper and you can run the lowest octane without trouble. but I don't know what it does to seals, and I may be wrong on the ethanol thing, not 100% sure.

 

If you don't mind could you elaborate on this a little, I'm very interested in the issues with the ecu and what can and can't be done to resolve them.

 

Modern car seals are unaffected by the 10% ethanol mixture but your power and mpg will be diminished because ethanol has only 60% or 70% the energy of pure gas.

 

I jsut recently had my Rx-8 shipped over to Germany and by my own mistake bought 86 fuel tickets (thats what I put in my beater) and found that at anything over 80 mph my oil light and my check engine light would come on. I used about half a tank before putting in some 93 and I have yet to see the lights come on even at a constant 135 mph. I guess my car loves the higher grades.

 

The rotary can run quite happily on nearly any type of fuel you can think of. The only thing stopping it is tuning. The factory ecu is tuned a bit agressively which sometimes limits it to higher octanes. This is easy to fix. Retune the ecu a little bit and you can make it run nice on whatever you want it to. You could get it to run on E85, 87, 91, etc and tune it to run the best on any of those. Good tuning will allow you to do nearly anything you want. Poor tuning limits you. To run good on 87 octane would only require some minor ecu retuning. It wouldn't even be much. It is certainly within the ability of any ecu options available right now. You won't get a noticable amount of power change doing this either. It isn't that great a jump. To run on E85, the maps would all have to be richened up quite a bit and timing would have to change but it wouldn't be hard.

 

i do not really know that much about the rotary engine in out 8's yet, but I have a quick question. I know premium is only recommended , but would using a lower octane fuel cause more carbon buildup, more likely hood of detonation, or any other adverse effects? Or should I stick with the premium Ive been using?