Does Octane Rating Matter for Gasoline? Thompson Sales Explains

December 14th, 2020 by

Yellow and black octane rating buttons at a gas station

You’ve seen the big yellow buttons at the gas pump. They say something about an octane rating for the fuel you’re about to buy. But what do these numbers mean, and does octane rating matter for your gasoline? Thompson Sales explains in today’s blog.

Meaning of Octane Ratings

The higher the octane rating, the better the gas resists knocking. Knocking occurs when gasoline detonates at the wrong time in the ignition chamber due to the compression the fuel undergoes.

Octane ratings usually come in three grades. Regular-grade gas has an octane rating of 87. Mid-grade is usually 89. Premium-grade gasoline is 92 or 93. The number indicates the percentage of iso-octane (a hydrocarbon found in gasoline) by volume in gasoline.

Do Higher Octane Ratings Matter?

The best idea is to follow the manufacturer’s recommendations for gasoline. Read your vehicle’s manual. If it says to use fuel with an octane rating of 87, filling your tank with a higher-octane fuel doesn’t provide any extra benefits to your engine.

If your vehicle manual says to use fuel with an octane rating of 89, going below that grade can affect your engine’s performance and fuel efficiency. The reason is that some high-performance engines, mostly found in sports cars and luxury cars, need mid-grade or premium gas to prevent knocking. Using a fuel with a lower octane rating than recommended by the manufacturer can damage your engine and cause emissions problems over the long term, leading to more expensive car repairs and maintenance. Bring your car into Thompson Sales if you hear a knocking noise, and our trained technicians will take a look for you!

How Does Knocking Happen?

Knocking happens when gasoline misfires and ignites prematurely in the ignition chamber, causing the pistons to push down with less force than normal. Occasional knocks won’t harm your engine. If knocking happens regularly, your engine could develop problems with fuel efficiency and power. High-tech computers can alter how a spark ignites the gasoline to prevent knocking, but your engine may run less efficiently because of it.

Follow the Manual

Simply follow the octane rating as outlined in your vehicle’s manual, and you’ll be fine. Thompson Sales can help if you have further questions about what type of gas is best for your vehicle.

Car Maintenance Tips by Thompson Sales

Thompson Sales prides itself on world-class customer service. Bring your car to our service department for seasonal checkups, and we’ll suggest ways to improve the fuel efficiency of your vehicle. Contact Thompson Sales or call (417) 763-6811 for more details.