If you were building a motor to run of ethonal e85 (85% ethonal 15% gasoline) what changes would make mechanically? I know you'd need a large amount of prom tuning, but are there other things that you'd do?

 

I would imagine the entire fuel system would also have to be corrosion (rust) resistant. Youd also need larger injectors (or more fuel pressure) as you need more fuel for a given ammount of air as ethanol is self oxygenating to an extent, not to mention a different fuel as well.

 

More tuning, hehe, the optimal stioch for E85 is like 9.0:1. The fact that you have lower compression could hamper you too. e-85 doesn't have the power per pound of fuel as Gas does (worded something like that). You should really have higher compression for e85, like 11:1 or even higher. (e85 has a octaneof like 110-114. Look around on the web and you should fine a good deal of interesting facts.