Im lucky enough to live in an area where I can buy both 93 octane and ethanol free fuel...just not at the same time.
Given the choice, would you rather have 93 oct R+M/2 10% ethanol, or 91 oct ethanol free?
My car is a weekend fun car and occasional autocrosser that doesnt come out to play in the rain or snow.
It can sit for a few weeks at time between drives and is stored indoors from Nov to April.
I like the thought of more ignition advance with the 93, but I know ethanol has problems with phase separation and water contamination. I'm thinking I probably pay for 93 but in a few weeks its turning to 91 in my tank regardless.
Any experts care to chime in?
Thanks