29th Dec 2020, 03:09

Not a myth actually. Using lower than recommended octane levels can damage a car & have severe carbon buildup. The opposite is also true. Manufacturers tell you 87 octane is fine because it’s cheaper. Consumers don’t like cars which “require” 91 octane. More expensive. Automakers know this. Those savings buying 87 instead of just going with 91 matter up until the point you spend 100x that much on a new engine.