[Chris Stewart]

Just remembering some things...alky "burns" cool. The alky dragsters & funny cars do long burnouts, back up slow, take a long time to stage then jump on the throttle, slipping clutches while holding a death grip on the brakes trying to build up extra heat before launching. You don't hear of them torching pistons either.

Alky, like many other liquids, boil at lower temperatures as atmospheric pressure decreases...like on a Colorado mountain. It could be "fizzing" the gasoline.
The late great Smokey Yunick built a motor for the Pike's Peak race with instructions not to fire the engine until you got to the race area...that mill musta had some real compression.

Now this may have an impact on the O2 sensor too since it's a thermocouple and needs a good deal of heat to generate the millivolt signal which the computer uses to determine injector squirt.