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How To know If Your Car Requires Premium Fuel To Operate Safely and Within Warranty

The octane requirement of vehicles can be tricky, particularly for those who are second or third owners. Here is how to know which gasoline is required to ensure proper operation and to satisfy your warranty requirements.


Which gas is required for your vehicle is not as easy to determine as some might think. Automakers don't have any standard octane rating that their vehicles require. Some run great on 85 to 87 octane gas, typically called "Regular Unleaded." Others require more octane for the engine to operate safely. And there is a third group that makes the issue fuzzy. Many manufacturers will rate their vehicle for safe operation using regular fuel, but will "recommend" a higher grade of fuel for more power and a more satisfying driving experience.

Your Vehicle Must Have Premium Gas If:
There are two ways to know if your vehicle requires premium fuel to operate without damage and in order to satisfy your warranty. The first is to look at the inside of the fuel filler door. Automakers place a warning label there if your vehicle needs premium fuel. You can also look at your owner's manual online, or if your vehicle still has one hiding in the glove box or trunk, the paper manual will tell you.

Automakers who require premium fuel are in the minority. Almost all are "Premium" or "Luxury" brands. Like with all luxury products, the idea is you pay more and get less. Our condolences on your fuel requirement. Your automaker's choice will increase your operating costs dramatically. We test over 300 new vehicles per year at Torque News. There is zero correlation between a fuel recommendation and performance within a category. The only exception, and it is very rare, is ultra-performance vehicles. If you own one of these, you already know it.

Your Vehicle Manufacturer Suggests Premium Gas, But Does Not Require It If:
Some manufacturers will rate a vehicle on both regular and also premium fuel. Mazda is one such company. Mazda will tell its owner how much additional power the vehicle will have with the higher octane fuel. For example, the Mazda CX-30 with its outstanding 2.5-liter turbocharged engine will deliver an impressive 250 horsepower and 320 lb-ft of torque with premium (93 octane) fuel. If you own this vehicle and opt to use regular fuel (87 octane) the engine will deliver 227 horsepower and 310 lb-ft of torque. Will you feel that difference in normal driving? You will not. However, if you are a person who drives assertively and wants to imagine the extra power is important to you, feel free to pay more. You will not violate the warranty if you opt for the regular fuel.

Other manufacturers sometimes rate the vehicle just one way and "recommend" premium for the best experience. That experience they refer to is the thrill you get when you read your car's specifications and are impressed by the numbers on the page. You won't feel the difference when you drive to work. Again, your car's fuel filler door and manual are where to find out what the lowest fuel requirement for proper operation and warranty compliance is.

It isn't just one mechanical engineer/vehicle tester that points to premium being wasted if your car does not require it. AAA conducted comparison studies using various fuels in the same vehicles to see how their performance changed. It didn't. AAA concluded that Americans waste $2 billion per year using premium fuels in cars with no benefits.

Your Car If Fine Using Regular Fuel If:
Almost all mainstream vehicles are just fine operating on regular unleaded fuel. Brand name fuel providers, sometimes called "Top Tier Fuel Brands" comply with an industry standard for detergent levels and you will not harm your car by using the lower-cost fuel. Also, you will not benefit from using the higher-priced premium with the nonsense about "Nitrogen!" and "Drive Your Engine To Cleanliness" marketing posters on the fuel pumps. Your automaker will include a detergent fuel line service in your periodic maintenance schedule if it is required. You don't need high-priced fuel to keep an engine "clean." Your manual or the fuel filler door will advise you what fuel is required.

Our recommendation is that unless you are shopping for a supercar, do not purchase any vehicle requiring premium gasoline. Your operating costs rise by thousands per year with zero benefits to your real-world driving experience. Better yet, opt for a plug-in hybrid vehicle like the Toyota RAV4 Prime. It has a cost for energy and cost of maintenance equivalent to an all-electric vehicle, but without the hassles associated with charging when you travel long distances. And it is the quickest vehicle in its segment. Toyota recommends 87 octane regular unleaded fuel for the Toyota RAV4 Prime.

John Goreham is a long-time New England Motor Press Association member and recovering engineer. Following his engineering program, John also completed a marketing program at Northeastern University and worked with automotive component manufacturers. In addition to Torque News, John's work has appeared in print in dozens of American newspapers and he provides reviews to many vehicle shopping sites. You can follow John on Twitter, and view his credentials at Linkedin


Frank (not verified)    September 24, 2021 - 5:58PM

When I drove from east coast to west a few years ago, I noticed that premium gas changed from 93 octane to 91 when I crossed the Mississippi. Anyone know why?

The Enemy (not verified)    June 21, 2022 - 9:27AM

In reply to by Frank (not verified)

Two reasons: first, the Midwest is All Things Corn, which includes ethanol in your gasoline whether you want it or not. Ethanol being an octane booster makes it easy to dial up the octane rating to 93. Second, higher elevations require lower octane. Once you get west of, say, Kansas/Nebraska/etc., elevation is high enough that 91 octane will have roughly the same knock resistance as 93 octane at or near sea level.

EDMUND GEORGE (not verified)    February 2, 2022 - 4:08PM

The literature on Mazda's 2.5 L turbo says it makes 250 hp using 93 octane. What does the engine make using 91 octane, which is the most common premium fuel in Calif?

EDMUND GEORGE (not verified)    February 2, 2022 - 4:09PM

The literature on Mazda's 2.5 L turbo says it makes 250 hp using 93 octane. What does the engine make using 91 octane, which is the most common premium fuel in Calif?