Butanol
Does not corrode parts like ethanol, can be blended with diesel fuel for soot reduction and anti gel formation. Reduced Hydrocarbons emissions by 95%, Carbon Monoxide to 0.0%, and Oxides of Nitrogen by 37% running it in a 1992 Buick Park Avenue.
92% of gasoline's BTU compared to ethanol at 70%. Huge improvement!
Mixes readily and completely with gasoline. Butanol can be produced at an estimated cost of 85 cents per gallon. Doesn't attract water like ethanol.
Is there a down side other than the Federal government does not subsidize it?
Ethanol sucks as a motor fuel in comparison. Put the butanol in your sled and go to Yellowstone! Then go over to West Yellowstone and drink beer with ethanol, the only place it should be!