87 octane gasoline, often called "regular" gas, is one of the most commonly used fuels in the United States. But what gives it that 87 rating is a word you've probably heard a time or two: Ethanol.
The answer is yes: You can mix 87 and 91 octane gasoline without blowing your engine to hell. With that out of the way, let's discuss what mixing different octane fuels does to your engine in terms of ...