The fuel system is not designed for it. I know people who have tried it and had problems. DiscipleRocks is one FF who has been running E85 for a long time IIRC.
Newer engine software might contain an algorithm to advance spark to the point of knock, and then back off X deg. It might test for this regularly to keep the most advance. It would be nice to know for sure, but that would explain your power bonus. Of course, the new Focus has compression ratios closer to what works best for E85 anyway.
I personally would like to see more interest in isobutanol myself. It reduces hydrocarbons more than E does, and doesn't cause fuel separation. Maybe in the next 10 years or so. Right now, it's an emerging tech, but E plants could be converted, and we wouldn't be 100% reliant on corn for fuel additives.
---The Complete How-To Archive--
Moderating everything now, let me know if I can help.
Originally Posted by the user formerly known as ZX3_Chick
You're special aren't you.