Fluids & Filters
Gasoline is a complex mixture of hydrocarbon-based components and additives that are specifically formulated for different climates and conditions. The properties of any given blend of gasoline must deliver good engine performance under a wide range of operating demands. There are gasoline quality guidelines established and are considered the minimum for a gasoline to be offered on the market. Companies often go beyond the guidelines to provide more unique formulations to meet specific motorist needs. Motorists in some areas of the country may also have access to use "reformulated" gasoline (RFG) to reduce emissions of ozone-forming (smog) and toxic air pollutants. RFG consists of a different blend than regular gasoline to reduce emissions.
Quite simply, gasoline provides the heat energy necessary to power the engine in most vehicles. Gasoline also contains various additives that may prevent deposits on fuel injectors and intake valves, guard against corrosion in the fuel system, and prevent icing of fuel lines.
As a motorist, the most important information you need to know refers to a gasoline's anti-knock index (AKI) -- a numerical representation of a gasoline's ability to resist engine knock, also known as "pinging." The AKI number is an average of the Research Octane Number (RON) and the Motor Octane Number (MON). This is the number displayed on the black-and-yellow placard at the gasoline pump. Because of the averaging effect of the two numbers, you may find that your car performs better on one brand of gasoline with 87 octane than another. It's best to follow your car manufacturer's AKI recommendation when choosing gasoline, although there is no advantage to using a gasoline with a higher AKI than is needed to run without knocking. Generally speaking, the AKI numbers at the pump reflect the "grades" of gasoline with names attached to escalating AKI numbers. Hence, "regular", "mid-grade" and "premium." These grades are somewhat of a misnomer, as they don't reflect overall better quality as AKI numbers increase; the numbers reflect only higher anti-knock capabilities.