Some short things to clear up about octane "definitions" for gasoline engines. First, gasoline engine engineers know what they are doing, when designing say, 87 octane gasoline engines. Therefore, when using 87 octane, ethanol-free gasoline(E0) in 87 octane designated gasoline engines, the most efficient results occur.... because 87 octane E0 gasoline IS 87 octane. Second, gov't forces designated 87 octane ethanol blends(E10) into our engines. However, the ethanol component is 114 octane. PLUS, the gasoline component is 84 octane, to arrive at mathematically designated 87 octane ethanol blend. Yes, none of the components of 87 octane designated E10 are 87 octane. That is why burning 87 octane E0, in my last five 87 octane, low compression ratio gasoline engines, over decades of use, have given 8%, 8%, 7%-8%, 7%, & 5% BETTER MPG than 87 octane designated E10 ethanol blends, which are used, but NOT burned efficiently in 87 octane designed gasoline engines. In addition, 87 octane E0, burned efficiently in said cars, are smoother, quieter & have "slightly" higher torque at low rpms, such that less down-shifting is needed, when ascending gentle hills with good feather footing techniques.