[darkpuppet]

Sunoco has ethanol in it, which runs leaner than non-ethanol brands... so yeah, switch to regular gas and your a/f may get skewed when you go into openloop.

I also know from reading around that ethanol produces less power per volume than gas, so I wonder if the knock-reduction properties of the higher octane would offset the power loss with the addition of ethanol... I tend to tune for 91 regular..

[edit]I also know (especially from r/c racing) that alcohol tends to love bonding with water, and has an increased tendancy to do so and separate from the gasoline as temperatures decrease. Yet, i'm sure that they put alcohol in the tank to act as a gas line antifreeze? I honestly don't know what explains this paradox..[/edit]