ethonal?
I was not aware that any manufacturer was taking ethanol blending into account yet for compression ratio, milage, etc but would be VERY interested to see that if you can find it. The only cars that are designed for it as far as I know are E85 cars, but that is a completely different ballgame.
The amount you lose is variable depending on the blend. Ethanol has upwards of 25-30% less energy than gas, so you would have to take that number and work it in on the percentage of the blend you were using to find how much to anticipate losing, all other things held equal. I have not researched extensively, but I believe different forms of ethanol may have less or more energy content in that general range. I have not looked into that yet.

