Why does premium gas have different octane numbers at different gas stations?

At some gas stations premium gas has 91 octane, others 93, and I think I've seen 94 at some.

Why is the octane rating for premium gas different at different gas stations?

4 Answers

  • 2 months ago
    Favorite Answer

    Different gasoline refineries add inhibitors in different amounts which sets the octane level/numbers.

  • Scott
    Lv 7
    2 months ago

    Octane ratings vary according to altitude. Gasoline sold in Salt Lake City (elev 4800') has higher rating than gasoline sold in Phoenix (elev 1000').

  • 2 months ago

    Different formulas.............

  • Geo
    Lv 6
    2 months ago

    Anything 91 or higher has the highest ability to prevent spark knock and detonation in any non race vehicle according to the standards set for gasoline engines. This allows the ECM/PCM to set the highest ignition advance it can for your engine, which means it can make the most power. Knock Sensors listen for spark knock and Retard ignition timing to stop it, reducing the available power...but not a lot. To your Question: Gasoline makers blend gas for their octane ratings, one part of the blend is actually Octane. There is more marketing buzz than anything for higher octane fuel than 91. Cars that require Premium fuel will get you Maximum ignition advance with 91 fuel, you won't get more with 94. But if it's the same price I'd use it...but don't think your car will be quicker. It won't. But if you had an old car with a Distributor, you could bump it up just a little more with 94. As usual, if you want good info Wikipedia is there: https://en.wikipedia.org/wiki/Octane_rating

Still have questions? Get your answers by asking now.