RX8Club.com - What fuel is best for an RX8?

RX8Club.com (https://www.rx8club.com/)

- Series I Tech Garage (https://www.rx8club.com/series-i-tech-garage-22/)

- - What fuel is best for an RX8? (https://www.rx8club.com/series-i-tech-garage-22/what-fuel-best-rx8-47974/)

Quote:

Originally Posted by UnknownJinX (Post 4936930)

Would be interesting to see an 87 vs 91 AKI dyno. That would do all the convincing there ever needs to be.

I agree that would be good to have a record of. Convincing? On this forum? It would depend on the tune, or if stock what flash, and then of course there would be more debate for years as to what is best.

Quote:

Originally Posted by DocWalt (Post 4936926)

Knock sensors on the Renesis do effectively nothing, BTW. Don't count on them to save you from bad gas.

So the knock sensor does not work on this engine?

Quote:

Originally Posted by Brettus (Post 4936928)

An untuned car is probably running very rich under load so maybe you 'get away with it' . Still bad advice IMO ...you need 91 or better ...particularly if engine is tuned for best power.

Brett, have you seen preignition under load on NA tunes?

Quote:

Originally Posted by UnknownJinX (Post 4936930)

Would be interesting to see an 87 vs 91 AKI dyno. That would do all the convincing there ever needs to be.

if only life were that simple

I had someone I respect insinuate that 87 was giving him the result you’re seeking above, for the usual 13B reasoning. I had to disagree though, but didn’t really press him on it. Beside the fact that a Renesis is unique from previous rotary engines, the Pro Formula Mazda race cars with Renesis engine ran high octane race fuel with premix. The highest output engine dynos posted on here by the same builder who was building those engines in the earlier series years were all running high octane, more than premium pump gas. I doubt they’d be doing that if all he had to do is run down to the gas station and buy the cheapest grade to make more power. That said, if changing to it would raise the output higher than the usual 265 - 270 bph numbers, then I’d like to be all over it. Which there are also some E85 dynos on here that suggest otherwise as well.
.
.

Quote:

Originally Posted by kevink0000 (Post 4936939)

Brett, have you seen preignition under load on NA tunes?

I have seen preignition under load on a tuned car running 87 octane (called 91 here) ................yes.

Well, I just followed the Owner's Manual on that one.

What about running a bone stock car on 87 vs 91 AKI?

locking this 17 year old thread as question has been asked and answered .
Use the recommended fuel; Premium.