Q: Why does my flex fuel vehicle get less miles per gallon with E-85 as compared to regular gasoline?
A: Ethanol has less energy (BTUs) per gallon. BTU stands for British Thermal Unit, a measure of heat. To illustrate, the amount of energy released by burning one wooden match is approximately one BTU. E-85 Fuel (85% ethanol/15% gasoline) contains about 84,000 BTUs per gallon, whereas gasoline has about 115,000 BTUs per gallon. Less energy per gallon results in lower fuel economy.