Your car either needs a high octane fuel or it doesn’t. The vast majority of cars fall in to the “doesn’t” category. The octane rating is a measure of the ability of fuel to resist “detonation” or exploding in the combustion chamber. Detonation becomes an issue with high performance engines but isn’t a problem with modern commuter car engines. Inside the combustion chambers of your engine the fuel is supposed to burn very rapidly–a sweeping “flame front.” It is not supposed to truly explode. If it should explode or “detonate,” a sound is produced that is known as “pinging.” It will be worst in hot weather and under acceleration. If extreme or constant it’s very bad for the engine and can cause a ton of damage. All kinds of factors promote or discourage this incorrect mode of combustion. These include, but are not limited to: compression ratio, humidity, outside air temperature, ignition timing, engine temperature, engine design and last but NOT least: the octane rating of your fuel. If your car requires high octane fuel it will require it all the time–or at least until the weather changes. Because fuel octane–contrary to myth–is in no way a measure of detergent properties, high octane fuel does not “clean out” your engine and has no residual effect. If your car pings only lightly and rarely on a low octane fuel use the cheap blend and save your money!
From your Local Mechanic, All Tune and Lube Total Car Care Tempe. Complete Auto Repair and Maintenance.