Right now I have a really good baseline 6 psi gas tune, I was wondering if I could throw some e-85 into it and still use feed back from the narrow band 02s? Or will the 02 sensors be trying to get to the gasonlines stoich and lean the car way out? I know I will need to add about 30% fuel across the board.

 

the only e85 tune i've done is a open loop one so im just going by theory. e85 still needs 14.7 it just takes more to get there. so if you have the 30% already added it should be fine.

 

Set injector constant aprox 30% lower than it ís and you will be pretty close.
Stock lambdas messures O2 so they dont bother what fuel you are burning.
Its no problem at all to run in closed loop, it just take a little longer to get there since E85 gives colder exhaust.