An interesting Autocar article on Stage Tuning (Hot Rodding) your MG TD from Stock (Stage 1, 58 HP) through Competition (Stage 3 - 5, Supercharged 90 HP).
https://www.mg-cars.org.uk/mgtd/mgtd_performing_midgets.htm
Something that I found particularly interesting is that at Stage 2 (Street) you’re running on 50% alcohol and at Stage 3 (Competition) you’re running on 80% alcohol.
Maybe we should be asking for more ethanol instead of less?
.E85 makes a good performance fuel. Race E85 is about 99 octane ((R+M)/2) and is very consistent in the mix. Pump E85 varies anywhere from 51% to 85% ethanol. For carb’ed engines that inconsistency is a BIG problem. For closed loop fuel injected engines, not so much.
Mileage will be far worse that on E10 but the cooling effect of pumping about 40% more liquid into the engine will help keep the engine cooler than running E10 or E0 gasoline. This is especially nice on turbo or supercharged engines.
Significantly higher compression ratios would yield better fuel mileage with E85, but that is impractical when almost everyone buys E10.
Higher compression will improve mileage but not enough to match E10. Especially when cars are already being built with 11:1, 12:1 and higher that will still run on 87 octane E10. The gains diminish as you get closer to auto ignition… about 14 or 15:1.
Indy cars were making 525-550 hp on 270 cubic inch 4 cylinder non supercharged engines in the early 50s on alcohol. Needed big fuel lines and big tanks,