The Difference Between Gas Grades

2014-02-07 15.48.26

Ever wondered why there are different gas grades at the pump? What are they for? Will a higher octane make your vehicle run better?

First and foremost, before you think about putting a new gas grade in your vehicle, check your owner’s manual.

Your owner’s manual will specify the correct octane for the make and model of your vehicle. Unless it’s recommended by your owner’s manual, it is not necessary to spend the money on a higher octane than required and we’ll explain why.

When you pull up to the pump, you’ll see three different octane grades: regular (87), mid-grade or plus (89) and premium (92 or 93). According to the Federal Trade Commission “octane ratings measure a gasoline’s ability to resist engine knock - a rattling or pinging sound that results from premature ignition of the compressed fuel-air mixture in one or more cylinders.”

The only time you’ll need to use a higher grade of gasoline than recommended is if you hear your engine knocking which typically only happens to a small percentage of cars.

While regular octane is recommended for most cars, vehicles with high compression engines may require mid-grade or premium gasoline.

High compression engines include sports cars, luxury cars or sport utility vehicles (SUV).

Premium gasoline contains a higher octane percentage. This is important because “when vaporized gas mixes with air and fills the combustion chamber, it is compressed by the rising pistons,” according to Edmunds, a top automotive resource. “This makes the gas-air mixture grow hot and it could ignite before the spark plug fires, pushing backward on the piston.”

Also, “higher-octane fuels can be compressed to a greater degree without self-igniting and that's why premium gas is used in high-performance engines.”

It is a common myth that using a higher than necessary octane will make your vehicle perform better.

Using a higher octane will cost you approximately 20-30 cents more per gallon (which can equal as much as $4 per fill-up) at the pump and will not improve your car’s performance.

According to Edmunds, many years ago higher octane did in fact contain additional detergents and additives to stop carbon deposits in your engine however due to government regulations all grades now have addictives to protect your vehicles engine and cut pollution.

Now you know!

Refer to your owner’s manual for the best fuel recommendation for your vehicle, stick to that and you’re good to go!

Sources:

http://www.consumer.ftc.gov/articles/0210-paying-premium-high-octane-gasoline

http://www.edmunds.com/fuel-economy/to-save-money-on-gas-stop-buying-premium.html