The E85 blend is used in gasoline engines modified to accept such higher concentrations of ethanol, and the fuel injection is regulated through a dedicated sensor, which automatically detects the amount of ethanol in the fuel, allowing to adjust both fuel injection and spark timing accordingly to the actual blend available in the vehicle's tank. Because ethanol contains close to 34% less energy per unit volume than gasoline, E85 FFVs have a lower mileage per gallon than gasoline. Based on EPA tests for all 2006 E85 models, the average fuel economy for E85 vehicles was 25.56% lower than unleaded gasoline.