89 Octane Ethanol free vs 93 Octane with Ethanol

[Patrón]

Originally Posted by kb9uwu

in the M3, I would run 93 octane with 10% ethanol vs 91 straight gas. In my lawn mower or any other small engine, I'd run the straight gas because ethanol eats them alive. Our cars are built to take 10%, even though ethanol sucks, mixes with water, and is less efficient than gasoline.

i think i'd even prefer 91 with 10% e over non ethanol 91 (little bit more octane). i'm fortunate to have 93 at my pumps and a few shell stations with e85.