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Q: What is Octane?

December 17, 2013 12:53 PM

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The octane rating of gasoline is important to know to give your car gasoline that will prolong engine life and allow your vehicle to reach its performance potential. A hydrocarbon, octane is added to fuels such as gasoline to eliminate preignition in internal combustion engines.

The octane rating of a particular type of gasoline is a standard measure that explains how well the gasoline performs. If the rating is high, the gasoline can withstand more compression than if the rating is low. High-performance engines need higher rated gasoline for optimal performance. This rating is based on the amount of anti-knock -- preignition -- properties in the gasoline. Octane is a colorless component that boils at high temperatures. When the octane begins to boil, the gasoline self-ignites. Gasoline also self-ignites if it doesn't contain enough octane. For this reason, gasoline that contains low levels of octane tends to self-ignite at lower compression than gasoline that contains high levels of octane. Thus, gasoline that cannot withstand compression is given a lower octane rating than gasoline that can withstand greater compression.

If you've ever heard a knocking or pinging sound in your engine, you have probably used gasoline with an octane rating that is too low. Knocking in the engine occurs if there is too much combustion in the engine due to the amount of engine compression. Specifically, the fuel ignites prematurely, causing excessive heat in the engine. If this problem is left untreated for a long period, it can cause engine damage. This can cause the car to become inoperative. Repairing an engine that has broken down due to excessive combustion can be very expensive.

In general, the lower the performance of the car, the lower the octane rating you'll need to drive it without risking the engine. In general, high-performance cars like sports cars and race cars require higher octane gasoline because their engines use high levels of compression to work well with these cars' high-power engines.

Most people don't pay attention to the octane rating on gasoline because standard gasoline allows them to drive their vehicles without any difficulty. However, if you hear metallic knocking or pinging sounds in the engine as you are driving, you need to find out what the octane level is in your gasoline and, more importantly, the recommended octane level for your car's engine, so you can increase it if need be. You also should have your engine checked to make sure there is no other problem contributing to premature combustion.

While using gasoline that is too low in octane can damage your engine, in most cases driving with a higher-than-needed octane rating won't harm it, but there's no point in doing so and it'll cost you more at the pump.

Although you might not have thought much about the octane rating of the gasoline you put into your vehicle, it's important to pay attention to it. Higher-octane gasoline is more expensive, but some cars require it. Lower-octane gasoline is less expensive, but it is 100% fine to use as long as you car's owner's manual recommends it.

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