Can You Mix Premium and Regular Gas?

Can You Mix Premium and Regular Gas?

Can You Mix Premium and Regular Gas?

One expense you can’t avoid if you drive a car with an internal combustion engine is refueling. Filling up your car with ordinary fuel could be tempting because gas prices are rising more rapidly than ever. But is it a good idea to combine premium and regular gas?

Both normal and premium gas can be used to power a variety of vehicles, and blending the two is usually safe. The amount of premium gas you mix with standard gas should be kept to a minimum if your vehicle needs high-octane fuel. This could result in a decrease in performance as well as detonation, which might harm the engine.

Continue reading to learn the distinction between premium and regular gas. This article will cover the effects of using both types of gasoline and the reasons why some vehicles need high-octane fuel.

What Sets Regular and Premium Gasoline Apart

Unleaded crude oil is used in both premium and regular fuels. The fundamental distinction between the two types of gasoline is their octane ratings, representing the fuel’s tolerance for inefficient engine combustion.

For the majority of automobiles with naturally aspirated engines, regular gasoline with an octane value of 87 is suitable. For automobiles with turbocharged or high-compression engines, premium gasoline with an octane rating of 91 or 93 is required.

Combining Regular and Premium Gas

Refueling with premium fuel won’t harm or benefit your car if your car operates on standard gasoline. Some people mistakenly think that using premium gas can improve performance or clean your car’s fuel system. Regular gasoline should continue to be used in vehicles that use it.

On the other hand, if your car needs premium gas to refuel, using regular petrol could be dangerous. So, if you’re running short on petrol and the station only has regular fuel, just put in enough to get you to the one with premium fuel.

The octane rating of your fuel will drop below 91 octane if you mix regular and premium fuel. The proportion of regular and premium fuel in your tank will determine the octane rating.

Boosters of Octane

If you must use standard gas on an engine that requires premium fuel, using an octane booster is one approach to keep your engine safe. Fuel additives called octane boosters raise the octane rating of your fuel.

Why Some Vehicles Need Premium Gasoline

While some manufacturers advise using premium gas for improved performance, others mandate it to protect the engine. Premium gas is typically advised for vehicles with high compression or forced induction engines.

Engines with Forced Induction

Premium gas is often needed for forced induction engines and engines with high compression ratios. Forced induction engines use turbochargers or superchargers to improve air intake. Cylinder pressure and compression are raised by allowing additional air into the combustion chamber.

Engines with High Compression

There are (naturally aspirated) engines with high compression ratios but no turbochargers or superchargers. High compression ratio engines are more thermally efficient and are able to generate greater power from combustion while consuming less fuel. A high compression ratio has the drawback of increasing the likelihood of engine knock, which is caused by too-early gas combustion.

High-Octane Fuel’s Advantage

High-octane fuels have a higher heat tolerance and burn more slowly, thus reducing the possibility of early ignition and engine banging. Regular gasoline is more likely to ignite spontaneously when subjected to heavy compression.

If you’re tempted to use conventional gasoline because it’s less expensive, just keep in mind that if your car needs high-octane fuel, a few pennies per gallon now could end up costing you more later.

How to Determine the Type of Fuel Your Vehicle Should Use

Regular gasoline works well in most vehicles, especially those with naturally aspirated engines. In order to compensate for decreased displacements due to the growing need for more fuel-efficient automobiles, manufacturers adopt turbocharged engines.

Since there are always exceptions to the rule, it would be incorrect to state that all high compression engines must operate on high octane fuel. One such instance is the turbocharged Mazda 3, which has a high compression SkyActiv engine and a horsepower number that the manufacturer bases on your fuel type.

It demonstrates that a car can run on regular gasoline even when it has a high compression, forced induction engine. This is because newer cars have electronic control units (ECUs) that can adjust engine timing to accommodate fuels with lower octane ratings. However, it doesn’t follow that all modern automobiles equipped with ECUs can do so.

Checking the back of your car’s fuel lid is the best approach to figure out what fuel to use. On the placard of the majority of cars, the minimum octane rating needed is stated. If your vehicle doesn’t have a sticker behind the gasoline lid, check your owner’s handbook or speak with the dealership.

Combining Fuel from Different Brands

Whichever gas station you visit, gasoline is practically the same. The distinction is in the type, amount, and quality of additives each gas provider uses.

A federal law known as the Clean Air Act seeks to lower and regulate air pollution nationwide. In order to comply with this requirement, the United States EPA (Environmental Protection Agency) must regulate the fuels and additives used in automobiles.

Fuel additives can enhance performance, reduce emissions, and clean fuel lines and injectors. Each fuel manufacturer is required to use a certain minimum amount of additives in their fuels. While more recognizable names like Shell and Mobil use more additives, less expensive ones frequently use the absolute minimum.

So while purchasing your fuel from various gas stations won’t harm your car, it’s a good idea to stick with popular brands since they typically contain better additives.


If your car doesn’t need premium fuel, mixing premium and standard gasoline won’t hurt you. The majority of vehicles requiring premium fuel have high-compression engines that can detonate or knock.

By altering their timing, some high compression engines’ ECUs can run on ordinary fuel. If your car’s maker mandates premium fuel, you should still refrain from blending premium and standard fuel.