It's not octane that matters. It's the fact that ethanol contains a lot of oxygen. This fact requires you to shoot a larger volume of fuel. If you have a translator and a commander or extender chip you can increase injector duty cycle to add the extra fuel needed. You'll might eventually run out of fuel as you increase boost. This might require larger injectors.
I,m assuming you have a 91 chip for gasoline. If this is true and you have the ability to add fuel to the program from idle up,it will work just fine. I have a chip that is burned for 72s and gasoline. To use E85 I use this chip to run 96s.
I have run 5 gallons e85 with 11 gallons no ethanol 91 octane in 2010 and 2011 without problems so far. That works out to almost 30%. I do have a translator and extender to richen up the mixture
You can set your base MAF on the translator to 10% rich. This will make everything throughout the rpm range 10% richer and your chip will adjust as much extra as it can. You'll no it's adjusted as much as it can if your BLMs reach 160. Anything less than 160 will work. On the commander and extender chips you can adjust the whole rpm range richer or leaner with an adjustable parameter called BLM correction. Does Turbo tweak have an adjustment that does this?
