Sorry guys, but ethanol has less energy (BTU/gallon) than gasoline, so car mileage has to go down with increased ethanol content.
Unleaded gasoline has ~116,000 BTU/gal.
Ethanol has ~76,000 BTU/gal, so the more ethanol is added to the mix, the more fuel is required to do the same job as pure gasoline.
Ethanol was originally added to gas many years ago to lower, IIRC, nitrous oxide exhaust emissions.
That's no longer a problem with today's engine management technology and catalytic converters, but ethanol gas persists as a product of Big Agra marketing.
IOW, you can't get blood out of a turnip. Or converted corn for that matter.