Now I might learn something new here. You have got me intrigued. If higher octane means LESS flamable - which based on concept I can comprehend - more parts oxygen and less parts fuel. Why would performance motors want higher octane fuels? This is assuming we're still talking about gasoline and not getting into other forms of fuels. Maybe the better question is where does fuel octane come into play with the combustion process? This may be a less educated thought but I guess I always assumed more octane, more power. Am I wrong?
Hi output motors have much higher compression ratios. The higher the compression ratio, the closer you get to the limit of pump gas.
What happens inside your engine is that your spark plug fires before the fuel and air mixture is fully compressed. This is called ignition advance. So what happens is you can dial in ignition advance up to where you get pre-detonation. OR you can run compression high and up to the point of pre-detenation (Old school guys will call this knocking, or pinging). Knocking, pinging, and predetonation can occur for a few reasons, but all result in a knock, or an explosion that occurs prior to the fuel being compressed fully..
In extreme situations like boosted scenario's, you have to run race gas, higher octane, less flammable fuel to allow the motor to not detonate. A combination of lower octane race gas and a somewhat std guideline of timing RETARD per PSI will get you the most power without pushing towards detonation.
Too much detonation can put a hole in the top of your pistons.
So you are/were wrong. More octane doesn't result in more power unless you've done something to take advantage of this higher octane fuel (Like advancing ignition timing, or raising engine compression by thinner head gaskets or cutting/milling the head surface down for better "seating".
Hopefully this sheds a little light on this for you.