It's only worth ~10whp NA. I see you've mentioned going TT since I answered and it's worth way more power there, or at least allows for more w/ a comparable safety margin. I'm not sure what you should expect to pick up boosted on E85 over 93 or 91, but Spooler or Hotrodz might could share some experience.

If he's going to run 91 and e85, he'll pick up a lot more hp on e85. He'll be able to run a lot more boost on e85. With my supercharger, I get knock above 13psi on 91 and I can run 17psi on e85 with no knock and could go higher. My 91 hp number is 480, my e85 number 680. 91 octane sucks!

Jeff; Just don’t forget the most important part...the tuning aspect from Ecutek,UpRev or whatever else is capable.
As mentioned earlier by another member; you burn a richer mixture with the increased ethanol content, with wot pulls getting in the single digit AFR’s.
Factor about 30% more fuel consumption over gasoline.
The HP gains N/A aren’t huge, but the torque gains will be more a bit more.
You got some great guy’s who’ve jumped on this thread to help, so I’d definitely be taking it all in :iagree:
Also, there’s a difference in weather the e85 comes out of the ground or out of a barrel....you want consistency :tup: