Think premium fuel is better than regular gasoline? You might want to think again. Many people think that premium fuel is higher quality, but the real answer is a lot more nuanced than that.
Today, we’re taking a deeper look at premium fuel, what it actually means, and whether or not it’s better for your engine (or MPG). If you’re curious if you should be shelling out more money for premium fuel, here’s the real answer.
What Are Octane Ratings?
At almost every gas pump, you’ll see a selection of two or three different types of gas. Each gas type has a big yellow button with a number on it like 87, 89, 93, etc. These numbers signify the fuel’s octane rating, which is basically a measure of how heat-resistant the fuel is.
Octane ratings matter because gasoline motors work by igniting air and fuel with a spark plug to create combustion. This is what powers your engine.
Before combustion, the fuel and air mixture is compressed to extract the most energy potential possible. When the mixture is compressed, it creates a massive amount of heat. Lower octane-rated fuels are less heat-resistant, so they can ignite too early and lead to decreased energy performance. It also causes “knocking,” which is the sound it produces in your engine when the fuel ignites prematurely. If you hear knocking in your engine, chances are you’re using the wrong kind of fuel.
All grades of fuel that you see at a gas pump (like regular, plus, and premium) come with an octane rating. Premium fuel is typically any gasoline with an octane rating of 91 or higher. Ninety-one and 93 octanes are the most common versions of premium gasoline available in the U.S. Sometimes you’ll see 93 octane gasoline labeled as “ultra” or “super-premium.”
Higher octane fuel like premium gasoline generally costs more than lower octane fuel. The higher octane rating means that the fuel can withstand higher temperatures before combusting, although that doesn’t always mean it’s better for your engine.
The best fuel for your particular engine is the one the manufacturer recommends. Many people think that just buying premium fuel will help their engine last longer, but that’s not entirely true. The right fuel for your vehicle is the fuel that’s right for the amount of compression and combustion in your engine. Your manufacturer will state this in the manual and sometimes right on your gas cap.
The difference between regular and premium gasoline is their octane ratings. Regular gasoline has an octane rating of 87, while premium has an octane rating of 91 or higher.
Sometimes, gas stations sell 89- and 87-octane gasoline side-by-side. You might see the label “midgrade.” Regular and midgrade gasoline options are less expensive than premium, but that doesn’t always mean that they’re less effective for your vehicle type.
There are many myths and misconceptions about premium gasoline. Premium fuel only benefits your vehicle if it’s the specific type of gasoline that your engine requires. Otherwise, you aren’t doing your car or engine any favors just by purchasing premium gas. You’re just spending more money.
Premium gas doesn’t give you better gas mileage or run cleaner. Higher octane fuel, like premium fuel, is better for high-performance vehicles like a Corvette, Mazda Miata, etc. Your vehicle owner’s manual will tell you whether or not your car requires premium fuel.
Of course, if you do have a high-performance vehicle, premium is the right fuel for your car. High-performance vehicles have higher compression ratios. Turbo-charged engines need more air and produce more heat during operation. In this case, using premium fuel helps prevent knocking in your engine.
Premium gas only increases your MPG if you drive a vehicle that requires premium gasoline. And even that is sort of a misconception.
Premium gasoline in a vehicle that requires premium gasoline doesn’t “increase” your MPG. It just keeps your vehicle operating properly, so you get the MPG that you should be getting. If your vehicle doesn’t require premium gasoline, buying it instead of regular fuel is just a waste of money with no real benefits.
Premium gasoline doesn’t last longer in storage than regular gasoline. Premium gasoline has a higher octane rating, which designates fuel stability, but that stability rating refers to heat, not longevity.
Different types of fuel have different lifespans, like gasoline versus diesel, but different octane ratings don’t. Conventional gasoline, whether regular or premium, will last anywhere from three to five months in your gas tank. If you want your fuel to last longer, use a fuel stabilizer.
You can put premium gasoline in a vehicle that requires regular fuel, but you’ll just be wasting your money. Although this fuel choice won’t hurt your engine, it’s also not doing you any favors.
Premium gasoline isn’t “better” than other gasoline; it just has a higher octane rating. The higher octane rating means it can withstand more heat for cars that produce more heat in their engines. If your car uses regular gasoline, consider yourself lucky that you don’t need to shell out more money to fill up.
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Most modern vehicles will run just fine on regular gasoline. If your car requires premium and your engine is knocking on regular fuel, using premium will eliminate that. Knocking will cause damage over time, but using regular fuel every once in a while is unlikely to cause damage.
In the past, using 87 octane in a car that needs premium fuel would cause issues from the get-go, but most modern cars today can handle it. Sometimes you just can’t find a premium pump, and that’s OK! Just don’t do it all the time.
Premium fuel is only worth it if your vehicle requires premium fuel. It’s really as simple as that. If your vehicle manual states that you should be using 87 octane fuel in your car, you’re just wasting money if you buy premium.
Premium fuel works in high-performance vehicles with higher heat levels in the engines. It won’t increase your MPG, make your regular-gas engine last longer, or store better than regular fuel. The only case where premium fuel is worth it is when you drive a car that specifically states in the manual that it requires a fuel octane level of 91 or higher. Have you ever needed premium fuel for your car?