?more octane = more power?

[330EXman]

i was wondering if more octane would help my quad. i have the modifications below. also if so what do i use, (one of those octane boosters?)

[optikid123]

its lets your motor run cooler and your usin a high comp. piston so i dont see how it could hurt you

[400exJOE]

Here's the deal: motors produce more power and run more reliably at lower temperatures. If you have a higher compression piston, you gain power in the higher compression, but not as much as you could because higher compression = higher heat, hence the inportance of higher octane fuel. Higher octane fuel keeps the heat lower. It also depends on your compression. Stock is 9.0:1 if I recall and they recomend premium or 92+ octane fuel. If you are now still no higher than 11.0:1 compression, you are ok on premium gas. If you're over that compression, you might want to look into a 50/50 mix of race gas. I would stay away from octane boosters just because I don't totally trust them.

here is my view on this topic.
octane is nothing more than a measure of the anti-knock quality of the gasoline. The only reason to raise the octane level of the gasoline would be to reduce spark knock or detonation due to insufficient octane levels in the gasoline.
Engines convert heat energy into mechanical energy. Heat is measured in btu's. Fuels have a btu rating. lower octane fuels have more btu's. higher octane fuels have LESS btu's.
You will yield more power if you can safely raise the amount of heat energy that is being converted into mechanical energy during the combustion process, whether it be from an increase in cpmpression ratio, timing advance, or btu's in fuel.
Therefore using a higher octane fuel than necessary will actually lower you power levels.
Using the lowest possible octane without causing spark knock will yield the best performance characteristics.

[thorspapa]

Ditto what Honda said, and here's more:

It seems that there's confusion regarding what "knocking" means in a motor, so here's a very simplified explanation:

If the octane level isn't matched to your compression (too low an octane rating), some of the fuel will have a tendency to partially ignite BEFORE the piston reaches the end of the compression stroke. This robs power, creates heat spots (because the mixture is burning longer due to the exhaust valves not opening fast enough, they're not due to open yet), and will eventually destroy the piston. It's trying to come UP, while the fuel ignited before its time is trying to drive it DOWN, only it CAN'T go down yet because it'd have to turn the motor backward in order to do so or break the rod (this can happen too): there's the extra heat and stress associated with "knockin", "pinging", or pre-ignition/detonation.

Now for using too high an octane rating:

Octane is one of the factors (just one of them) that determines when the fuel will burn. If the compression isn't high enough to cause full ignition at the end of the compression stroke, then not all of the fuel will burn, or burn as hot as it should. The lack of a big "boom" and the heat it produces (heat is power too) will also decrease the power your motor COULD produce. It damages nothing, as pre-ignition does, but it keeps the motor from fully achieving it's possible output by lowering the efficiency of the power stroke.

That's why you should use only the fuel octane your motor needs, not more, not less.

As for guidelines for octane use, look in the FAQ, there's a thread there where I posted a simplified guide to compression vs octane needed.