[Christ]

The thing about having 2/3 the BTU/vol is that you use more volume (much larger jets) when you run alcohol in a gasoline engine. So the BTU per stroke is the same-ish, or more if you're making substantially more power on alcohol.

What I'm thinking is that since the alcohol's explosive reaction is so much faster from start to finish, that the metal of the engine may not have as much time to soak up the heat before the expansion of the cylinder area allows it to begin cooling and the upstroke starts pushing it out the exhaust. Merely conjecture on my end, I have no idea.