On my 2010 5.4 the stock E85 tune was rated as 10 hp more than the gas tune. I was hoping that since the Forscan turned on an E85 setting that it would at least be a little increase of timing and fuel trim that increased some power.
In my 2014/6.2 I'm running a 93 tune.
In Michigan 93 is $4.92, I get 11.5 mpg, drive 300 miles per week which is 26 gallons for $128. E85 is $2.59, I estimate 8mpg based on 11.5x.70, which calculates to 37.5 gallons for $97. If 7mpg, 42.85 gallons=$111. If 6 mpg which would be a way worse than normal drop, 50 gallons=$129. In this case it saves some money every week.
If I was running regular at $4.02 and 12 mpg it would cost me $100 which doesn't save any money compared to E85. If it increased power enough it may be worth smile factor. I mean, people already buy mufflers, tunes, intakes,,,, and that kind of stuff. Most of those only add 5-15 horsepower too.