Things to Know About Different Types of Gasoline - Subaru Service Questions in Salt Lake City, UT

If you're like many people, when you drive up to the fuel pump, you press the button for the cheapest gas and let that suffice. But is that the best option? Are different types of gasoline better or worse for the engine of your Subaru than others? At Nate Wade Subaru, we'll take a look at some different varieties of gasoline and what they mean for you.

Gas pumps with different octane ratings labeled

4. Premium Gasoline

Regular unleaded gasoline generally has an octane rating of 85 in Utah. Look at the buttons next to this one and you're likely to see one with 87 on it, as well as one with an octane rating in the 90s. This highest one is usually labeled "Premium." Premium gasoline can withstand greater compression before combustion occurs. Some engines, like the one you'll find in the Subaru WRX and the Subaru BRZ, require this type of fuel. This is because their engines have higher compression ratios. If you were to use regular unleaded gas in these cars, it might combust before the spark could ignite it, damaging your vehicle's engine.

If you drive a Subaru that doesn't require premium gasoline, using it won't give you any benefit at all. Premium fuel doesn't have any special qualities or added detergents that make it better than regular gasoline, and you won't see any boosted performance or a cleaner engine from using it. Unless you feel like giving the gas stations extra money, stick with the fuel type that your vehicle calls for.

One more note on octane ratings. In most states, the minimum octane rating is 87. Because of our higher elevations, states like Utah and Colorado will often sell 85-octane gasoline.

Gasoline in a lab being placed into a vial with a pipette

3. TOP TIER™ Gasoline

All gasoline is required by law to have detergent additives in it. These additives help keep your engine clean and free from carbon buildup. But many companies only use as much as they are legally required to. TOP TIER™ gasoline is different. TOP TIER™ companies go above and beyond, adding extra additives to help your engine run even cleaner. Using this gas can reduce the need for fuel injector cleanings and even help improve fuel economy. Though it usually costs a little more, the long-term benefits of using TOP TIER™ gasoline are well worth it.

2. E15 Gasoline

Most of the gasoline you'll find at stations in the United States contains a component known as ethanol. Ethanol is a biofuel that's made from plants, generally corn and sugarcane. It's added to gasoline in an attempt to reduce the environmental impact. But many engines aren't designed to run on much ethanol, which is why gasoline sold as regular unleaded can only contain up to 10% of this compound. E15 gasoline is gas with 15% ethanol added. Although gas stations may say that it's safe for use with any car that was manufactured in 2002 or later, be careful. Subaru only approved the use of E15 on some of its models within the past few years, and using it on older models may void the warranty.

Person giving a thumbs-up sign while their car is being filled

1. E85 Gasoline

If you know that E15 is gasoline with 15% ethanol, it makes sense that E85 is gasoline with 85% ethanol. While it might be OK to use E15 fuel in a Subaru manufactured since 2018 or so, the same is not true of E85. This fuel is designed for special engines in vehicles known as FlexFuel vehicles. If you put it in the engine of your Subaru by mistake, you will likely notice differences like reduced engine performance and the check engine light may come on. One tank of E85 in a car not made for it probably won't do any long-term damage to the engine, but it's still worth double-checking before adding fuel to your Subaru.

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    1207 South Main
    Salt Lake City, UT 84111
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    • Sales: (888) 586-8323

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Nate Wade Subaru

1207 South Main St
Directions Salt Lake City, UT 84111

  • Sales: (801) 658-9379
  • Service: (801) 328-1327
  • Parts: (801) 328-0061