Gentlemen, please keep in mind that the air/fuel ratio for ethanol is about 9:1. This means that you use much more ethanol per horsepower, or per mile than gasoline. I would say a maximum of 8-9 mpg. Yes, you can get more power from an engine on ethanol, and even more from methanol (6.5:1 AFR), but you can't get better mileage per gallon.

-Scouder