Originally Posted by goregasm
Actually ethanol only decreases performance in a car that wasn't made to handle it. Ex: Koenigsegg CCXR Edition, something like 810rwhp on regular pump 93 octane. I believe more than 1100HP on E85. (not sure of the exact numbers, but it's significant, at least 150HP increase)
i'm pretty sure he was referring to the comparison of pure gas and gas + ethanol with the same octane rating.
ethanol in itself produces les power per unit volume than gas at the same octane. E85 has a very high octane rating that can allow you run very advance timing or a lot more boost. you could do the same with pure race gas at 110 octane but the the cost of race gas was something like $7.50 a gallon 5 years ago. i have no idea what it is now.