Regular Gas vs. Premium Gas: What Fuel Type Does Your Subaru Need?

Subaru cars are known for their impressive performance and reliability, but one question that often arises among car enthusiasts and owners is what type of fuel to use for best results. The debate between regular gas and premium gas has been ongoing for years, and Subaru owners are not exempted from this conversation. In this article, we will discuss everything you need to know about fuel type for Subaru cars, and which type of gas is best suited for the job.

Subaru Fuel Type

Subaru cars are designed to operate using regular unleaded gasoline with an octane number of 87 or above. The company strongly recommends using only gasoline containing no more than ten percent ethanol (E10). Using gasoline with more than ten percent ethanol (E15 or higher) can damage engines and fuel system components.

Subaru Legacy and Outback models with a turbocharged engine, such as the WRX, require high octane premium gasoline with an octane number of 91 or above. Failing to use premium gasoline in turbocharged engines can cause engine knocking and reduced performance.

Regular Gas vs. Premium Gas

The difference between regular gas and premium gas is the octane rating, which is the measure of a fuel’s ability to resist "knocking" or detonation in the engine. Premium gas typically has an octane rating of 91 or higher, while regular gas has an octane rating of 87 or lower.

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The engine control module (ECM) of Subaru cars can adjust the engine’s timing and other parameters to accommodate different octane ratings of gasoline automatically. Still, running a car designed for regular gas on premium gas will not offer any additional performance benefits and merely ends up wasting money.

Benefits of Using Regular Gas Over Premium Gas

Using regular gas in a Subaru car when it’s recommended can offer some benefits over premium gas. The first is that it’s cheaper than premium gas, and regular gas is available in nearly all gas stations. Other benefits of using regular gas include:

  • Lower emissions: Regular gasoline burns cleaner than premium gas.
  • Better fuel economy: Regular gas has a lower energy density compared to premium gas, which means your car’s engine burns less fuel and ultimately yields better fuel economy.
  • Best option for non-turbocharged engines: Since regular gas is recommended for non-turbocharged engines, it offers adequate engine performance without the cost of premium gas.

Drawbacks of Using Regular Gas

Using regular gas in a Subaru car may have some drawbacks, even though it’s recommended if your car is not designed to operate using premium gas. Some possible downsides of using regular gas include:

  • Reduced power output: Cars designed to use premium gas rely on the higher octane fuel to achieve maximum power output. Therefore, using regular gas in such vehicles may result in lower power output.
  • Engine damage: If you use gas with a lower octane rating than recommended, engine knocking may occur, which can damage the engine over time.
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Following the Manufacturer’s Recommendation

The manufacturer’s recommendation for fuel type should always be your primary consideration when deciding what type of gas to put in your Subaru car. They understand the engine and fuel system’s technicalities and determine the best fuel for optimal engine performance.

In addition, using a higher octane rating than the manufacturer’s recommended may not be better for engine performance. It might even harm the engine over time due to constantly burning fuel with higher octane ratings.


Q: Can I use premium gas instead of regular gas in my Subaru car?

A: For cars with non-turbocharged engines, regular gas is the recommended fuel, while turbocharged engines require premium gas. Using premium gas when it’s not necessary will not offer any performance benefits, and might end up being more costly.

Q: Will using regular gas damage my Subaru car’s engine?

A: No, using regular gas on non-turbocharged Subaru engines when it’s recommended will not damage your engine. However, using gas with a lower octane rating than recommended may cause engine knocking, which can damage the engine over time.

Q: Will using regular gas reduce my car’s performance?

A: If your car is designed to operate on regular gas, using it will not reduce performance. However, cars designed for premium gas might experience reduced performance and power when regular gas is used instead.


Choosing the right fuel type for your Subaru car is vital to ensure optimal engine performance. While premium gas might seem like the best option, it’s not recommended unless your car is designed to use it. Regular gas is the most cost-effective solution for non-turbocharged engines, and it has lower emissions and better fuel economy than premium gas. Always follow the manufacturer’s recommendations for fuel type to ensure your engine runs efficiently and smoothly for many years.

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Davis Bellew

As a Subaru owner and enthusiast, Davis has a deep understanding of the needs and concerns of Subaru drivers. He specializes in writing informative and engaging content about Subaru maintenance and repair, and his articles are always well-researched and easy to understand. When he's not writing, he enjoys hiking and photography.

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