[lkchris]

Since tetraethyl lead and MTBE are now illegal, the major octane booster added to our gasoline is ... ethanol.

I've never understood how high octane can be achieved without an additive, and most places that offer ethanol free gasoline state 87 octane or something. I'd really like to know how a high octane ethanol free gasoline can be produced these days. The real test might be in a vehicle without octane automatic adjustment.