10 months ago
Last edited at 12:41PM on 2/12/2013
it means it has a higher combustion rating. Which means it takes more pressure to make the fuel combust. Using a higher combustion rated fuel in a vehicle that isn't made for it, will decrease the fuel efficiency because it makes it harder for the spark plug to ignite the fuel, and will wear on the plugs. Only use a higher octane rated fuel if it is recommended by the manufacturer, or if you have a high combustion piston and cylinder head. It will not increase fuel economy, so save your money and buy the cheapest gas.