There is a certain threshold that fuel holds, based on octane, that controls detonation. After you reach a certain compression ratio, say 93 octane will be unable to control detonation, no matter how much fuel you use. Race fuel containing lead and more methonal are able now to control detonation at a much higher level.
…i’m no chemist, so i’m sure there is someone out there that can lay some facts down much better than me.