
Originally Posted by
exodus
[nitpick]
You can advance the timing as much as you want and it's not going to detonate. Traditionally detonation/knocking is the air/fuel mixture igniting without a spark (too much heat due to compression). The "knocking" bit happens when you have preignition due to heat... and secondary ignition due to the spark plug. When the two flame fronts collide, you get a "knock."
[/nitpick]
With advanced ignition timing you want to use a higher octane (slower burning) fuel so that the flame front doesn't hit the piston before it's TDC, to prevent damage to the rod/piston/bearing. This will generally push your peak power to a lower rpm.