E85 on Diablo tune - high altitude

[Black Knight]

I am wondering if I need to make adjustments if I am running E85 on the Diablo 93 tune - like adding more fuel. I know with the factory tune the car will add more fuel to the mixture automatically and I would think if it has been running too lean for this long I would have problems, but I am wondering if I would benefit more from adjusting the mixture parameters for E85.

I know the real answer is to buy a custom tune from... wherever... but just wondering meanwhile is there anything I can adjust or need to in order to get the best performance out of running E85? Only one station within 15 miles of my home has 93+ gasoline, and I figure why bother running the 87 or 91 tune. As title says I drive at high altitude - 5280+ feet above sea level. Suggestions?

[mikel]

you cant adjust any part throttle stuff, so it will be 20-25% lean everywhere except WOT, and you may not evven be able to add enough fuel at WOT...you answered your own question, you NEED a custom tune

[Black Knight]

That's what I figured, thanks for the response. Guess I will mix some 91 in with the E85 in the meantime.

Is it true one notch lower octane rating is OK to use at high altitude?