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True or False: Your car needs higher octane gas

True or False: Your car needs higher octane gas

By Carolyn Hauck on June 18, 2015

Ever wonder when you pull up to the pump if you should be paying for premium gasoline instead of your usual regular? Especially when gas prices are high, that extra 10-25 cents you could pay on higher octane fuel can start to add up, so is it really worth it or even necessary? To understand if your car needs a higher octane, it helps to understand octane and what it does first.

Octane is a highly compressible hydrocarbon found in crude oil and gasoline. It’s desired compressible properties avoid something called knocking in your engine. Knocking in your engine comes from combustion in the cylinder before the spark ignites the fuel and can destroy an engine over time. Scientists designed ratings to measure the anti-knock properties of really any type of fuel, based on octane. These are the numbers we see at the pump, such as 87, 89, 92, and they do not always or necessarily refer to the percentage of octane by volume in the fuel, but rather the fuel’s anti-knocking properties.

So back to the question at hand: does your car need higher octane to run better?

To find the answer, we turned to Terry, a top mechanic on JustAnswer for his explanation, and his response was the same as the research we found:

“Most engines these days are designed to run on an 87 or higher octane, whereas a high compression engine would be designed to run on a higher octane, (91 or higher) and a lot of race cars run 100 or slightly higher. Gasoline with an optimal octane rating performs best in an engine designed to run on that octane level. So, higher isn't always better.”

Add to that: most newer cars have an anti-knocking sensor in the engine, which makes the point of using a higher-octane fuel moot. Your car would sense whether or not there is knocking in your engine. As Terry goes on to recommend, “If you have any concerns about which grade of fuel to use, check your owner’s manual.”

Gasoline does contain other additives, such as detergents and preservatives, that refiners use to refine the crude oil, and some people prefer one brand’s gasoline to another brand’s depending on these additives, but that’s where preference really ends. Higher octane ratings only really matter for cars that require high octane fuel, such as high-performance vehicles or race cars.

Final verdict? False. Your car doesn’t need higher octane to run better.

Talk to top Mechanics like Terry and others about tips to keep your car performing optimally.