I have been running E85 in my civic for almost two years. It's been great, but the fuel economy has suffered. I just finished increasing the compression ratio of the engine. I used p29 pistons on a d16y8 crank. I think the compression increase and the displacement decrease will net me about the same fuel economy that I had on gas. I'm still breaking in the engine, but I think I'll have burned through a tank in a month. Then we'll see how it did. I already notice slightly more power.

Here's some details of what I did

samnet.sytes.net/civicSX.html