Endurance Racing - What Octane?

[magpiemini]

I have gotten some good advice so far so why stop now?

Remember, this is LeMons endurance racing. I know the engine has been ported, how much I have no idea. It seems to run on the street just fine with Union 76 91 octane.

For endurance racing, is good pump 91 octane sufficient or should I step up to unleaded 100 or ??

Any additives besides the good premix oil?

I don't need your opinion if you don't race or autocross, thanks anyway. I am not trying to be rude, just don't like the clutter.

[wanksta]

My teams 24hr Chump Car runs on 93, but I know my FC runs best on 87. 87 and premix is my vote.

[Pete_89T2]

Unless its got a turbo or supercharger on it, save your cash and run it on 87 octane regular. SA/FB/FC series & old school normally aspirated rotaries will all run fine on the lower octane stuff. Not as sure for the Renesis RX8 engines, as those run higher compression ratios, and may require the higher octane fuel like a turbo would.

[cshaw07]

low octane and premix, disable your omp.

[lokirx706]

As stated above low octane is all you will need. You will gain no power in running 91 in an 84 GSLSE. I doubt you will notice any difference at all really.

High octane (91/93 and above) is for knock resistance in high compression, or forced induction engines. It sure wont hurt to run it, but why bother? Save yourself some cash!

[Van330ci]

I have been told the engine will run cooler with 100 octave race gas, is this true or a mith?

[lokirx706]

Originally Posted by Van330ci

I have been told the engine will run cooler with 100 octave race gas, is this true or a mith?

I was told by a gentleman that builds aircooled Volkswagens that is does. However it isnt a very significant change, perhaps only a few degrees. They would do it if they were worried they might get stuck in traffic. I am not using this as factual information, simply stating something I was told by a 'mystic' VW owner...

I would assume this would be much less noticeable on a water cooled engines. And probably not even noticeable at all, at the compression ratios most N/A rotaries operate at.