Can I Use Regular Gas When Owner’s Manual Recommends Premium?

Everyone who drives wants to keep their costs of operation as low as possible. Paying less for gas is something we think about every time we pull up to the pumps. Regular gas costs a significant amount less than premium — but what if your car’s manufacturer recommends premium? Do you have to use premium and pay extra for the privilege? Let’s cut through the confusion and get you a straight answer.

What’s the difference?

Regular and premium gasoline are very similar. They both start as crude oil, and both are built from the same hydrocarbon building blocks at the refinery. The primary difference between them is in their octane ratings. This is the number that you see next to each gas pump when you stop in to fill up. Regular gas has a lower octane rating (usually between 87 and 89), and premium gas has a higher rating (typically between 91 and 93).

The significance of the octane rating is that a higher-octane fuel will resist pre-ignition, or knocking, better than a lower-octane fuel will. Pre-ignition means that the fuel-air mixture in the cylinders ignites before it should, which can cause driveability issues, as well as engine damage if it persists.

This is something that can be a major issue in higher-performance engines, which are built to operate at higher temperatures and cylinder pressures, compared to the average vehicle. The higher-octane fuel helps these engines run properly, without the potentially damaging effects of pre-ignition.

What type of gas should you put into your car?

Just as with many other automotive-related questions, the actual answer is “it depends.” We will refer you to that great source of automotive wisdom, your owner’s manual. Look for the section on fuel, and you will find the manufacturer’s recommendation for the correct type to use. There are three potential scenarios that cover most vehicles on the road. Let’s take a look at each of them:

Regular gasoline is recommended for your car: Your manual recommends regular, and nothing but regular. That’s all you need to use, and you should never have any need to use premium. If you sense any knocking or other irregularities in the way your engine runs, call a mechanic. The problem is unlikely to be related to your choice of fuel.

Premium gasoline is required for your car: The owner’s manual requires you to use premium fuel. Period. This means that your engine was built to operate on a higher-octane fuel, and it will likely suffer from harmful pre-ignition if you use regular. Stick to premium and enjoy the extra power.

Premium gasoline is recommended for your car: If your manual states that premium is recommended, but not required, you have options. Vehicles that recommend, but do not require you to use premium, are letting you have your cake and eat it too. These cars have engine computers that can adjust to run on both lower-octane and higher-octane fuels. Their maximum power ratings were generated by running on premium, which lets them boast of the highest possible horsepower in their advertising. But these cars can also run just fine on regular, even though there will be a slight loss of power when you do so.

Try a tank of premium, followed by a tank of regular. You will probably not notice much of a difference from running on regular during everyday driving. But if you were to take a trip with your vehicle fully loaded, or you plan to tow a trailer, it might be worth it to use premium and get those extra horses back. The choice is yours.

Be sure to use Top Tier Gasoline

Top Tier Gasoline keeps your engine cleaner for smoother operation in the long run, and is available in all octane grades offered by those brands that sell it. It costs about the same as gas found at non-Top Tier brands, and is well worth seeking out. In fact, many carmakers recommend it for use in their vehicles.