E85 is 100-105 Octane, much higher than 93 Octane premium gasoline. Can run more timing advance, higher compression, more boost .. if you engine is mapped to leverage E85, you can get a big performance boost.
Good information! I wouldn't have thought e85 is cheaper per mile than 93. I wonder how different 87, 89, and 93 are. If it would be any better to run e85 on a daily.
Yeah, this is the right way to look at it, cents per mile, not MPG. It's all been worked out, E85 is cheaper per mile, not because it's cheaper to make, but because the Renewable Fuel Standard forces a set number of gallons of ethanol/biodiesel to be sold, and it's hard to reach it because of the limit for normal gas at E10. Refiners are subsidizing E15 and E85 to get people who can to use it to buy it.
Don't forget the horsepower increase from E85. Depending on the vehicle, 30-40 hp difference isn't unheard of. Probably why the fuel economy drop was more significant from 65 to 75 mph with the 93 vs the E85.
It seemed like the 93 dropped significantly more than the 85 when you increased to 75mph. I wonder if you increased speed enough if the 85 would eventually have better gas mileage than the 93
