Race Fuel
It depends completely on why you're putting it in.
The norm is to tune for the octane or more precisely the burn-speed you have.
If you're putting it in to slow burn speed, then you don't neccessarily need to do anything. Raising octane is a fairly good form of protection/insurance for the engine, but it is normal to lose some power unless the tune matches the octane.
Some high octane fuels also have higher specific gravity or density so that also will change tuning requirements.
I could better answer if I knew why you were using the extra octane.
The norm is to tune for the octane or more precisely the burn-speed you have.
If you're putting it in to slow burn speed, then you don't neccessarily need to do anything. Raising octane is a fairly good form of protection/insurance for the engine, but it is normal to lose some power unless the tune matches the octane.
Some high octane fuels also have higher specific gravity or density so that also will change tuning requirements.
I could better answer if I knew why you were using the extra octane.
Unless it is heavily oxygenated and you retune for it, it won't help your times at stock compression n/a. You can't just look at octane ratings, you also have to look at fuel composition. Some have a lot more oxygen than others.
Originally Posted by Dmoney
I'm at 10:8:1 compression and the race fuel is Sunoco 104 and if I do use it what do I need to change in the tune?
It would take some tuning time on your part to determine how much to raise the SA and possibly reduce the AFR until the tune matched the 104 correctly, but then you'd probably be back to where you started performance wise.
In general, only engines with increased DCR or cylinder pressure can take advantage of race fuel.
