I’m no expert on E85, but I did speak to lots of people and do lots of research on it before starting to run it in my GTR last April. I put about 8K miles on E85 until switching over to 93-octane in October and for me with identical mods and only tuning changes, E85 netted ~55whp and ~105wtq.:excited Again, I’m not an expert, but on E85, I’m running only 2lbs more boost, so I suspect the bulk of the gain is coming from the more aggressive timing possible due to the octane gain.
The only thing to watch is that E85 differs from race gas in that the % of ethanol varies dramatically depending on the season (higher ratio of ethanol in summer, lower ratio in winter). Not sure how other car’s ECU deal with it, but in mine, I have two different maps I run depending on the season to avoid rich/lean conditions. Works well, but I still decided to switch over to 93-octane for the winter, for better cold starts, availability and I just don’t need the performance benefits E85 allows on winter roads. Also, for people w/o cats, E85 also doesn’t leave the black residue near the exhaust outlet that 93-octane does.
Go ahead and make the switch to E85. Then tell your friends, so demand picks up and more locations start carrying it.