Unleashing the Power: How Aftermarket Exhaust Headers Boost Subaru EJ 255 Horsepower

Subaru EJ 255 is a popular engine among car enthusiasts who desire a powerful and dynamic car that can perform well on the road. To enhance its performance, many Subaru EJ 255 owners turn to modifications such as installing aftermarket exhaust headers. But do aftermarket exhaust headers really increase horsepower in a Subaru EJ 255? In this article, we will examine this question in detail and provide you with all the information you need to make an informed decision about upgrading your car.

What are Exhaust Headers?

Before we delve into the benefits and drawbacks of installing aftermarket exhaust headers, let’s first understand what exhaust headers are and how they work. Exhaust headers are a component of your car’s exhaust system and are responsible for collecting exhaust gases from multiple cylinders and redirecting them to the exhaust pipes. The design of the headers can have a significant impact on the performance of the engine.

Stock exhaust headers are designed to meet a variety of requirements that may not prioritize performance. On the other hand, performance exhaust headers are designed to increase the engine’s efficiency by optimizing the flow of exhaust gases. These headers are usually made of high-quality materials such as stainless steel or titanium and feature larger piping than stock headers. This increase in pipe diameter reduces the amount of resistance the exhaust gases encounter when flowing through the exhaust system, improving the flow and increasing the engine’s horsepower.

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Boosting Horsepower in a Subaru EJ 255

The Subaru EJ 255 is a turbocharged engine that already boasts a respectable amount of horsepower. However, installing aftermarket exhaust headers can boost that horsepower even further. By increasing the diameter of the headers, the amount of exhaust gases that can flow through the system increases, allowing the engine to breathe more efficiently.

Additionally, aftermarket exhaust headers reduce the backpressure in the exhaust system. With less resistance to overcome, the engine can more easily push the air out of the cylinders, resulting in improved horsepower and torque. Subaru EJ 255 owners who install aftermarket exhaust headers can expect to see gains of up to 15 horsepower, depending on the quality of the headers and other modifications made to the engine.

Pros of Installing Aftermarket Exhaust Headers

In addition to increasing horsepower in your Subaru EJ 255, installing aftermarket exhaust headers offers a variety of additional benefits. These benefits include:

  • Improved sound: Aftermarket exhaust headers are often designed to give your car a louder and more aggressive sound, which is ideal for car enthusiasts who love to hear the engine rev.
  • Better fuel economy: By optimizing the flow of exhaust gases and reducing backpressure, aftermarket exhaust headers can improve your car’s fuel economy and save you money on gas.
  • Improved overall performance: By increasing horsepower and reducing resistance in the exhaust system, aftermarket exhaust headers allow your engine to perform more efficiently overall.

Cons of Installing Aftermarket Exhaust Headers

While installing aftermarket exhaust headers can provide numerous benefits, there are also some drawbacks to consider. These drawbacks include:

  • Expensive: Aftermarket exhaust headers can be expensive, especially if you opt for high-quality materials such as titanium. You will need to balance the benefits of installing headers with their cost.
  • May affect your warranty: If you install aftermarket exhaust headers on your Subaru EJ 255, it may affect your car’s warranty. Be sure to double-check the terms and conditions of your warranty before making any modifications.
  • May require tuning: Installing aftermarket exhaust headers may require your car to be tuned to optimize performance. This additional tuning may be expensive and time-consuming.
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Frequently Asked Questions

Q: Will installing aftermarket exhaust headers damage my car’s engine?

A: If installed correctly and paired with other modifications, aftermarket exhaust headers should not damage your car’s engine. However, improper installation or pairing headers with incompatible modifications could potentially cause damage.

Q: Do aftermarket exhaust headers void the warranty on my Subaru EJ 255?

A: Installing aftermarket exhaust headers on your car may void your car’s warranty. It’s important to read the terms and conditions of your warranty and consider speaking with a qualified mechanic before making any modifications.

Q: Can I install aftermarket exhaust headers myself?

A: While it is possible to install aftermarket exhaust headers yourself, it is recommended that you have a qualified mechanic perform the installation. This will ensure that the headers are installed correctly and paired with other modifications for optimal performance.


Installing aftermarket exhaust headers can be an excellent way to increase horsepower in your Subaru EJ 255 and improve overall performance. However, it’s important to consider the pros and cons associated with this modification and ensure that it’s the right choice for your car. By understanding how exhaust headers work and the benefits they can provide, you can make an informed decision about upgrading your car’s exhaust system and unleashing the power of your Subaru EJ 255.

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Peter Banks

With years of experience as a professional mechanic and Subaru specialist, Peter is one of the most respected members of our team. He's written several articles on Subaru maintenance and repair, and his advice and tips are always practical and helpful. When he's not working on cars, he enjoys cooking and trying out new recipes.

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