Here’s the key: is premium required? Or simply recommended?
If premium is recommended, but not required, you could save a few bucks – or more– every time you fill up the car. But you need to know if your car really needs premium. If it does and you use regular fuel, do you risk damaging your engine?
It’s a confounding question that has a lot of drivers spending more money than they should either unnecessarily on premium fuel or worse, on extra maintenance because they didn’t put the right fuel in their car.
How to Tell If Your Car Needs Premium Fuel
Go open up your fuel door, open your car’s manual or look at your door jamb. Go ahead, I’ll wait.
Now that your neighbor has watched you checking these places on your car and wondered what you were doing, you should know the type fuel the manufacturer of your car specifies.
If your car specifies a minimum octane rating of 87, enjoy the savings and go buy yourself those red-soled shoes you’ve been eyeing. If the manufacturer specifies an octane of 91 or higher is recommended, you can use regular fuel but your car may not perform to the top specs advertised: the engine may only put out 298 horsepower, not the full 306.
If the manufacturer requires an an octane of 91 or higher, the engine in your car is designed to burn a higher octane fuel; using regular gas may result in higher maintenance costs and lower fuel economy.
Some engines are designed to burn premium. Generally, performance engines, track cars and high-end super cars require premium. The rest, even all those turbo engines, can burn regular fuel.
What Does the Octane Number Mean?
The higher the octane number, the higher the temperature it takes for the fuel to detonate in the engine. The higher temperature can cause the fuel to combust earlier than the spark plug would have dictated. In essence, the engine wouldn’t be in perfect timing harmony. However, modern engines have sensors that can pick up on the octane level and the computer can adjust accordingly, avoiding engine damage and accommodating for the type of fuel used.
Typically, regular unleaded fuel is 87 octane. And also typically, manufacturers recommending or requiring premium fuel specify 91 octane or higher. So of course it’s not easy to buy 91 octane. Mid-grade is typically 88-90 octane and premium is 91-94 octane, with 93 octane most commonly found at gas stations. So even if your car’s manufacturer specifies 91 octane you’e probably paying for more octane than your engine really needs.
You Think You Need Premium … But You Might Get Away With Regular … Take This Test
If you were to accidentally fill up with a lower octane fuel or decide to save a few dollars on a fill up, your engine should be fine even if the manufacturer specified that premium fuel is required. Simply monitor how your engine performs with the lower octane. If you feel the engine struggling or making any unusual sounds, premium fuel is the answer. Also check your fuel economy; if your MPG drops like a rock that’s a sign that your engine performs more efficiently with a higher octane fuel.