I have done some tuning on my motor on E85, mostly at a dyno in Klamath Falls OR at 4300 ft. I have since reinstalled the original jets (that fuel teted to be E75 winter mix )but I haven't jetted it up at the track yet on back to back test to see if it wants richer or not I do test the E85 now and find that when the fuel sits in the plastic fuel jugs or metal cans over a period of time the Ethanol content increases, not decreases due to the gasoline evaporating out of the fuel I had 15 gallons sitting in three different containers in the race car trailer since last October, one can and two jugs. They tested in May to be between 87 and 90 % I need to buy some pure Ethanol or at least E98 so I can play with mixing it with the fuel I have to get all of it to a set level of Ethanol instead of having 10 to 15 % differences in batches