Does High Octane Gas Improve Mileage

Does a High Octane Rating Improve Gas Mileage?

Updated November 23, 2013

When you pull into the gas station, you usually have a choice of regular, super, and premium gasoline. Many motorists believe that super or premium gasoline, which is significantly more expensive than regular gasoline will increase fuel efficiency, and is therefore, worth the higher price. Unfortunately, in most cases, this simply isn’t true. Your automobile will run most efficiently with the gas recommended by the manufacturer or in your owner’s manual. For most cars, this is regular gasoline.Regular gasoline has an octane rating of at least 87, super gasoline has an octane rating of between 88 and 90, and premium gasoline has an octane rating of at least 91. But what, exactly, do those ratings mean for your car and its performance on the highway?  Gasoline undergoes two tests to determine its octane rating, which measures the fuels tendency to knock or “ping” when mixed with air in the hydrolytic cylinder of a car engine. It’s called octane because it is rated against the fuels ability to prevent knock or ping compared to pure hydrocarbon octane, which has a rating of 100.  Basically, the rating compares the “anti-ping” or anti-knock” performance against pure hydrocarbon octane. Please note, that all engines “ping” a bit when operated at full throttled.  If your engine is “knocking” regularly or it is noticeable, make sure you get it checked out so it won’t cause serious damage.

Check with Your Manufacturer

Almost all of the new cars on the road today have fuel-injected engines that need to use a gasoline with a detergent additive. Cars only need high octane gasoline if it is recommended by the manufacturer.  Generally, if your car is designed to run on 87 or regular octane gasoline, it will not run more efficiently or get better gas mileage with a higher grade gasoline. In fact, if switching to a higher octane gas does improve mileage, there may be a problem with the engine, and you should have it looked at by a mechanic.

A higher octane gasoline will not provide your car with more power, either. Your car is designed to run most effectively and efficiently on the gasoline identified in your owner’s manual. While higher rated gasoline may be more refined, that doesn’t mean that it’s a better product. More refinement results in a different blend of hydrocarbon, which burns slower than regular gasoline. These additional steps, and not the quality of the product, are what increase the price.

Tune Up for Better Gas Mileage

You have many choices when you head to the gas station to fill up your gas tank. Unless your car’s owner’s manual specifically identifies super or premium gasoline, neither the mileage efficiency nor the power of your auto will be increased by filling up with the pricier options. Don’t know what the manufacturer recommends and can’t find the owner’s manual? A quick internet search or phone will save you money at the pump.  If you are looking to increase fuel efficiency and the life of your automobile, you will be better served spending the additional gas money on regular tune-ups and maintenance.

Raymond Perez is an editor at Car Care Coach. Visit for more tips.



Calvin Escobar
About Calvin Escobar

The Car scene is so diverse Where I come from, most enthusiasts recognize the amazing engineering (particularly the engines). The bulk of the ridicule originates from the manner in which many of the vehicles are modded/maintained. Thus, the jokes and or hate tends to be aimed more at the owner rather than the machine. All of which makes seeing properly sorted old Toyota's and Hondas at car meets, auto shows, and track days all the more refreshing.

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