[sphinx]

Yes. But at mid level blends the ethanol mileage penalty disappears. The engine manufacturers are very interested in higher ethanol blends as one possible way to meet next generation mileage and emissions standards.

[SunTzuWu]

But at mid level blends the ethanol mileage penalty disappears.

No it doesn't. Mileage is dependent on the amount of energy available per gallon as measured by BTU's per gallon. The higher the gas/ethanol ratio, the lower the BTU's. There is nothing magical about ethanol. It's just a filler.

[Dr. Sivana]

But at mid level blends the ethanol mileage penalty disappears.

How can the penalty disappear when there are fewer BTUs (joules, calories, etc.) in the same volume of fuel?