Brighter Planet's blog
This morning’s NPR marketplace included a list of money-saving tips for drivers. Most are spot-on, but one surprised me: the recommendation that everyone use 91 octane premium gasoline.
Numerous sources including the Federal Trade Commission, Scientific American, and the California Energy Commission have debunked the myth that a higher octane rating will give you a performance boost or keep your engine cleaner. Possibly alluding to this, the tip claims that premium gasoline is better “because it’s more filtered, not because of the octane.”
Since all grades of gasoline have the same energy content I’m skeptical that any slight difference in purity could make up for a roughly 7% price premium.
My take: follow the other tips but stick with regular unleaded.