Many drivers are aware of the different grades of gasoline available at the pump.
Unleaded versions come in regular, plus and premium varieties, which correlates to the octane of the gasoline. The octane rating of gasoline tells a driver how much the fuel can be compressed before it spontaneously ignites, rather than igniting normally from a spark plug in the vehicle engine. Lower-octane gasoline can withstand less compression than higher-octane gasoline.
Gas that ignites on its own rather than from a spark from the spark plug causes knocking and pinging, which can damage the engine, so it is important to use the right octane level of gasoline for a vehicle, based on the car's compression ratio for the engine. Car engines that are rated in a particular way will benefit from the correct octane in gasoline.
Higher-performance engines commonly found in race cars and sporty, luxury vehicles will generally require a premium, high-octane gasoline to run at their optimal performance. Most cars on the market are built to take regular 87-octane gasoline. Higher-octane fuel costs more per gallon than the lowest octane. Over time, filling up with premium gas can be a significant factor in how much it costs to own a particular vehicle.
Using a higher octane fuel in a vehicle that is not rated for it will not increase performance, it only will end up costing more. That's because the octane rating does not refer to how much power the gasoline will put out. Premium gas will not improve gas mileage or give the vehicle
more "oomph" if the engine is not designed to accommodate a higheroctane fuel.
It is always wise to consult with the owner's manual to determine the type of fuel that will offer the best performance in the car. Those shopping for a new vehicle should pay attention to octane ratings and not assume that every car they test drive is best when running on regular octane.
