I have ran, on an occasion or two, E85 in my flex fuel truck. It was almost 50 cents per gallon cheaper than regular gas. Guess what, you definitely get what you pay for. At the time, my truck averaged 12.4 in town. When I put E85 in it, it averaged 9.5. Would I do it again? NO.The Elio will be compatible with up to E15. I asked Elio this question in an e-mail in April.
Most of the gasoline now sold contains some ethanol, but the exact amount varies by region. In general, the ethanol content does not exceed 10% by volume. Gasoline with 10% ethanol content is referred to as E10 and with 15% ethanol as E15. E85 means there is 85% ethanol and 15% gasoline. Most of the gasoline with more than 10% ethanol is sold in the Midwest.
All gasoline vehicles can use E10. Currently only light-duty vehicles with a model year 2001 or greater can use E15. Only "flex-fuel" vehicles can use gasoline with an ethanol content greater than E15.
The energy content of ethanol is about 33% less than "pure" gasoline, although this varies depending on the amount of denaturant that is added to the ethanol. Thus, vehicle fuel economy may decrease by up to 3.3% when using E10.
I hope this helps.