Flame speed: gasoline vs ethanol?

Question

I'm wondering does ethanol burn faster or slower than gasoline, and by how much? (Flame speed not quantity)

Also assuming the engine could handle it, does anyone know roughly at what rpm these fuels could no longer burn fast enough to keep up?

Answer 1

Surely it's impossible to say at what RPM the speed of the flame-front means that the burn isn't complete at the end of the combustion stroke without knowing the diameter of the piston, volume of the combustion chamber and stoke of the engine.

A small diameter bore with a long stroke will mean that the flame-front has less distance to travel and more time to do it in. A large bore with a short stroke is a combination which will be more susceptible to hitting a flame-front speed RPM limit.