Originally Posted by JStang
I am mixing 93 octane with E85. I put 5 gallons into my tank followed by filling up with 93 octane from Shell. 5 / 16.2 = 30.864%. I understand that 93 from shell contains "up to" 10% ethanol so maybe I have too much ethanol.
I assume that it is better to err on the side of too much ethanol versus too little, no?
Yeah, rather more than less. Your fuel trims look fine.