Which would you run in your car (assuming it's 87 octane friendly)?
87 octane regular unleaded without ethanol
or
89 octane mid-grade with 10% ethanol
By me they're the same price, and I get nearly equal performance, MPG, and the same amount of knock (Knock Retard when I'm scanning) no matter which one I choose.
Ethanol seems to be a very poor booster of real world anti-knock ability, since the amount of KR I see on the scanner on 91 octane with ethanol is only slightly lower than on 87 non-ethanol. 89 non-ethanol is a better KR fighter than the 91 with ethanol.
Since there's really nothing different about either one, what's there really to gain other than a (possible) reduction in emissions, and support of local farmers?
87 octane regular unleaded without ethanol
or
89 octane mid-grade with 10% ethanol
By me they're the same price, and I get nearly equal performance, MPG, and the same amount of knock (Knock Retard when I'm scanning) no matter which one I choose.
Ethanol seems to be a very poor booster of real world anti-knock ability, since the amount of KR I see on the scanner on 91 octane with ethanol is only slightly lower than on 87 non-ethanol. 89 non-ethanol is a better KR fighter than the 91 with ethanol.
Since there's really nothing different about either one, what's there really to gain other than a (possible) reduction in emissions, and support of local farmers?