2 of 26

Yes

Write now Article Tools

The science behind fuel grades is counter-intuitive. Most would assume that the higher octane rating would indicate a higher level of volatility, but the opposite is actually true. The answer to the question of what grade of gas is better is not a yes or no answer.
In a car recommended for premium-only fuel, the premium is a better choice, but for a vehicle that does not indicate any preference, the lower grade fuel will be better. There are many more variables that should be considered to answer this question accurately.

To explain the combustibility of various levels of fuel one has to think in reverse. The higher the grade of fuel, the lower the combustibility. Using premium fuel in a vehicle designed to tolerate regular will actually compromise mileage and power to a minuscule extent. The reason for this premium grade being recommended for high performance vehicles is that they generally have higher compression ratios, possibly forced induction (turbochargers or superchargers,) coupled with aggressive ignition timing and lean fuel mixtures. Without going into a lengthy diatribe, all of these characteristics of a higher-performance engine are in pursuit of every last drop of potential horsepower. Using regular in these cars is definitely not recommended, however, most modern fuel injection systems will adapt to the more combustible fuel by detecting knock (preignition)and adjusting fuel mixtures and timing accordingly. The performance of these engines will be compromised slightly in this situation as will gas mileage.

A larger concern for the fuel consumer should be where they are purchasing their gas as opposed to which grade they are selecting. The impurities in some cheap, questionable gas stations could pose a larger problem than the grade selected. Some companies, like Shell, tout the purity of their fuel and even augment their fuel with additives to make for a happy fuel system.

If your vehicle does not have a decal on your gas cap, or near your fuel gauge indicating the use of premium, save your hard earned pennies and get the cheap stuff. With those extra accumulated pennies, invest in a tire pressure gauge and routine maintenance that will make a much larger impact on gas mileage and vehicle performance than fuel selection ever will.

Learn more about this author, Steve Boisvert.
Click here to send author comments or questions.

Add your voice

Know something about Is regular grade gasoline just as good as premium gas for your car??
We want to hear your view. Write now!