What is the difference between regular and premium gas?

What is premium gas?

Premium gas is a 91- or higher octane gasoline designed to fuel high-performance engines. A higher-octane rating means the fuel is better balanced and stabilized against spontaneous combustion, which can cause knocking and damage to a car engine. Premium gas may also contain additional, higher-quality additives compared to regular gas. However, premium gas might not be necessary or improve efficiency for cars that are designed to run on regular gas.

What is regular gas?

Regular gas is an 87-octane fuel. Octane ratings measure fuel stability. The higher the octane number, the more stable the fuel. Most cars on the road run on regular gas.

Does higher octane gas last longer?

No, any fuel efficiency gained using premium fuel would stem from engine performance, not the gas itself. Using premium gas with a standard engine won't make your vehicle more fuel efficient.

Does premium gas improve gas mileage?

If your car is designed to run on premium gas, it can increase fuel efficiency and decrease emissions. If you have a luxury or performance vehicle with turbochargers or high-compression engines, you may benefit from premium gas's resistance to engine knock, which allows you to accelerate more smoothly.

Check your owner's manual to see which gas type your manufacturer recommends for your specific car make and model. Note that the definition/label for premium gas can differ from state to state and station to station. Some of the various names for automotive fuel with high octane levels of 91-94 include: Premium, Super Premium, Ultra and Ultimate.

What cars require premium gas?

Cars that require premium gas have an indication inside the fuel filler door and in the car's manual. The indication will typically specify the minimum octane rating necessary, which can be important if you have multiple premium options to choose from. Some cars that need premium need at least 91 octane, and others may require at least 93 octane.

Turbo-charged cars that need premium gas

• Chevrolet Camaro
• Chevrolet Corvette
• Subaru WRX
• Toyota Supra
• Kia Stinger

Luxury cars that need premium gas

• Audi A3
• Cadillac XT5
• Lexus ES
• Lincoln Aviator
• Range Rover Sport

If the owner's manual recommends premium gas instead of requiring it, you can typically operate the vehicle safely on regular gas. Still, you may not reach the performance and fuel economy indicated in the car's specifications. In most cases, the difference in performance is small and something you may not notice during normal driving.

If the car is designed for regular gas — or doesn't specifically say that the car requires premium gas — go with regular. There are no benefits to putting premium gas in a car that doesn't need it.

What happens if you use premium gas instead of regular?

It's unlikely that your car will be harmed if you use premium gas in a car that requires regular gas. But it's a near-certainty that you won't see an increase in performance and a fact that you'll pay more for premium.

Does insurance cover damage from using the wrong fuel?

Your auto insurance typically won't cover the costs of damage related to using the wrong fuel. If you use the wrong fuel, stop your car immediately to avoid any damage. Call a towing service, and take your car to a mechanic to have the car's system flushed and drained.

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