It’s Okay To Mix Premium and Regular Unleaded Gas


When it comes to what fuel you need to add to your car tank, you’ll agree with me that there are several different options out there. There is regular unleaded gas, which usually comes with an octane rating of 87, is the most common type of fuel used across the world. Another type of fuel is mid-range gasoline – it has an octane rating between 88 and 90.

Another type of fuel is premium gas; it is usually referred to as high octane, and that’s so because its octane rating falls between 91 and 94. When it comes to filling the tank with fuel, experts say sticking to the recommended gas for your car is important. But here’s a question; is it bad to mix premium and regular unleaded gas in the same fuel tank?

There’s nothing bad in mixing premium and unleaded gas in the same tank. When you do this, what you’ll achieve is a mid-range type of fuel with an octane level between 88 and 90. Regardless of the type of fuel recommended for your car, the vehicle will most certainly survive the mix, as long as you don’t do it regularly.

What exactly is premium gas and why is it important for some vehicles? What is unleaded gas and what does it include? Can I mix premium and unleaded gas in my car? Find out the answers to these frequently asked questions in the rest of this article.

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What is premium gas and why is it essential for some cars?

As previously stated, premium gasoline is any type of fuel gas that has an octane rating of 91 and above. In the US, any gasoline with an octane value of 93 is considered super-premium.

So, why exactly is this type of fuel recommended for some vehicles? Well, to answer that, I’ll say that a couple of factors can contribute to why your vehicle needs to run with premium gasoline.

For instance, if the car is equipped with a turbocharged engine, using higher octane fuels, such as premium gas, is important. In case you don’t know, the octane rating has a lot of effects on your car engine’s performance and compression. That said, with a higher octane fuel, you’ll surely achieve more performance for your turbocharged engine.

Another reason why it’s recommended for you to use premium gas is that you are using a pretty high-performance vehicle. That’s not all; it’s also possible that the car comes with a high-strung engine, especially those that perform with tight tolerances.

The bottom line is; premium gas is a higher octane fuel with a rating that falls between 91 and 93. So, if your car manufacturer states in the manual that you should use this type of fuel, you need to stick to it.

Can you use regular unleaded gas for a car recommended to use premium gas?

Automobile manufacturers often advise their buyers to stick to a certain type of fuel for their cars. Let’s say it’s recommended for you to use premium gas for the vehicle, can you go ahead and use regular unleaded gas?

As previously mentioned, if it’s recommended inside the car manual to use premium or high octane fuel, it’s best if you don’t do otherwise. There’s a reason why your car manufacturer told you to do that.

Here’s the thing; premium gasoline is designed to burn more slowly in your car engine. When it burns slowly, the fuel is expected to produce a uniform flame propagation inside your cylinder. Using regular unleaded fuel for this type of engine will only reduce the performance of the engine. Matter of fact, unleaded fuel will mostly end up causing engine knocks to your car.

So, to answer the question; I will say yes, you can always use regular unleaded gasoline for a premium gas- recommended vehicle. However, when you do that, you may be putting your vehicle’s engine at risk of knocking, as verified by 11 Alive.

What is regular unleaded gas?

Unleaded gas is gasoline without any lead additives which were used to prevent engine knocking. Around 1970 when lead was discovered to be toxic unleaded gasoline was introduced. Regular refers to a octane level of 87 as opposed to premium gas which is 89 or higher.

As you now know, regular unleaded gas is the most common fuel across the world. Well, that’s so because it’s very inexpensive and often recommended for most car engines. Unlike premium gas, unleaded gas comes with an octane rating of 87.

Should you use premium fuel in a car that runs on regular unleaded gas?

So, here’s a quick question; is it bad to use premium gasoline for your car that runs on unleaded gas?

Of course, you can always use a higher octane fuel in place of regular unleaded fuel for your car. According to North Shore Honda, a Honda dealer, no serious harm will happen to your vehicle when you do that. Here’s what the dealer said regarding the question below:

“If you accidentally put premium fuel into your regular gas car, nothing significant will happen.”

So, it now comes down to the question of why you’re using a premium fuel instead of the regular one? Did you mistakenly use it or you wanted to switch to achieve a higher engine performance?

If it’s accidental, it’s fine but if you’re doing it because you heard that it’ll improve your engine performance, that’s just a myth, according to experts.

Can I mix premium and unleaded gas in my car?

People often ask whether or not it’s good for them to have a mix of premium gas and regular unleaded gas in their car. If you’re also interested in getting an answer to the question, here’s what you need to know below:

Having a mix of premium and unleaded gas in your car will do your vehicle no significant harm. That’s so because when you combine the two fuels, what you’ll get is mid-range gas, and this will not harm your “turbocharged engine” if you don’t use it continuously.

If you’re using the mix for a car recommended to use regular unleaded fuel, no harm will be done to your engine. However, you may be spending money unnecessarily by doing just that continuously.

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