Niagara Gazette — TOM: Fuel octane has nothing to do with the quality of gasoline or how the car will perform. It has everything to do with how the gas acts in the combustion chamber environment. If your carmaker suggests you use regular octane fuel (87) then use it. Using a higher octane will not make your car run better.
Irene brings up a subject that a lot of people ask me about, and one that is commonly misunderstood. Let’s take a closer look at why Irene should use regular gasoline.
What is octane? Fuel octane is a measurement of a fuel’s volatility factor in the combustion chamber. In simpler terms, octane is a measurement of how the fuel combusts in the hot combustion chamber environment.
Can I use regular gas (low octane) in my high performance car? Different octane gas was developed to accommodate different grades of performance engines. The higher the performance engine, the hotter the combustion chamber environment, and the higher the octane used. If low octane (regular) gas is introduced into a hot, high compression combustion chamber found in high performance vehicles, it pre-ignites, creating a condition called “engine knock.” Why? When the low octane fuel enters the combustion chamber, it ignites prematurely. The result is the ping or engine knock you hear. Over time, continued engine knock results in damage to the tops of pistons, cylinder head faces, and valves. I have seen literally hundreds of high performance engines where the cylinder heads, piston faces, and valves were melted due to the constant use of low octane (regular) gas.
Can I use regular gas in my high performance car in a pinch? Sometimes you go to fuel up and the gas station is simply out of high-octane fuel. So what do you do? Go ahead and use regular to get to where you’re going, but don’t make a practice of it. Remember, “continued use” of low octane fuel in a high performance engine will damage it over time. Built into the performance system of today’s engine is a device called a “Knock Sensor.” The sensor constantly measures combustion chamber pressure. When it senses excessive pressure from pre-ignition, it sends a signal to the ECM (Engine Control Module) to back off on ignition timing. This feedback system minimizes the effects of using low octane fuel. Note I said minimizes, not eliminates. Continued use of low octane fuel in a high performance engine will damage it over time.