• E85, also called flex fuel, is an ethanol-gasoline blend containing  51% to 83% ethanol, depending on geography and season—summer blends tend to have more ethanol while winter blends have less.4 E85 can be used in FFVs, which are specially designed to run on gasoline, E85, or any mixture of the two. FFVs are offered by several vehicle manufacturers, and we provide a brief guide to help you determine if your vehicle can run on flex fuel.
  • Cost. The cost of E85 relative to gasoline or E10 can vary due to location and fluctuations in energy markets. Though typically cheaper per-gallon than gasoline, it is often slightly more expensive on a cost-per-mile basis.
  • Performance. Drivers should notice no degradation in performance when fueling with E85. In fact, some FFVs perform better—generate more torque and horsepower—running on E85 than on gasoline or E10. 6,7
  • Availability. More than 2,300 filling stations in the U.S. sell E85. Visit the Alternative Fueling Station Locator for service station locations.

Reference: http://www.fueleconomy.gov/feg/ethanol.shtml