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Does a Muffler Add Horsepower? If So, How Much?

A zoom in photo of a smoking double exhaust pipe of a sports car ready to go.

I remember one of the best tricks to add pizzazz to my car back in my school days was to install a cherry bomb muffler. A muffler not only takes a mundane vehicle and makes it sound like a beast, it can add more horsepower to the vehicle, but how?

This article explains how mufflers, also called “silencers” in some areas, can add horsepower to a vehicle and how much the horsepower increase might be. A muffler can be a vehicle’s best friend, sounding incredible with an additional power punch and looking good while increasing fuel mileage.

However, it is essential to remember each muffler is made for a specific car or model, so make sure the muffler is correct for your vehicle.

How does a muffler work?

A muffler has a deceivingly simple design that is quite effective. The muffler contains a series of tubes and pipes with strategically placed holes that can cancel sound or enhance the engine roar depending on the design.

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A muffler is typically made for canceling engine noise from engine exhaust gases by passing the gases through pipes and chambers. They are designed for sound waves to bounce against each other and effectively reduce exhaust noise.

A good muffler reduces sound, improves airflow, and allows the engine to breathe more effectively. Increased airflow for engines can have two significant benefits:

  1. Better gas mileage with less-restricted airflow.
  2. Improved horsepower with efficient engine exhaust.

What are the primary types of mufflers?

These are five main types of mufflers to consider for this discussion.

1. Turbo muffler

A zoom photo of a Porsche Panamera Turbo I exhaust muffler.

turbo muffler is a type of restrictive muffler that allows airflow in a direct path. This muffler is considered an upgrade over factory exhaust systems with an excellent sound and can increase horsepower.

The quiet sound quality is excellent and achieved by flowing gas through an S-shaped path that flows through the muffler before being forced out of the muffler tube.

Due to its straightforward design, this two-stage design can increase horsepower as the engine gas is released into the atmosphere. In addition to helping horsepower, a turbo muffler can also help keep the engine cooler with improved airflow.

Does a turbo muffler add horsepower?

Yes, depending on the vehicle, horsepower, and engine, a turbo muffler can add up to 10% horsepower with enhanced airflow.

Will a turbo muffler affect mileage?

Since the primary objective of this muffler is to manage airflow better, maximizing engine horsepower will not affect mileage, so don’t expect changes in mileage.

How expensive is a turbo muffler?

A turbo muffler is worth looking at since its manageable cost, depending on the brand, of $50-$100, can be an inexpensive way to put more “zip” into an engine with maximized horsepower.

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2. Straight through (cherry bomb) muffler

A photo of straight through muffler also known as cherry bomb muffler isolated in a white background.

The glass pack muffler, which I affectionately call the cherry bomb muffler, is a straight-through type muffler that allows maximum power and exhaust flow. The fiberglass-packed design has holes running down the pipe with muffling courtesy of the fiberglass packing.

This straight-through muffler creates a deep, throaty sound that adds character to any vehicle. Typically painted a bright cherry red, the glass pack muffler has been very beloved since its introduction in 1968.

A bonus is that the straight-through design allows excellent airflow, maximizing the engine’s horsepower and managing unnecessary backflow build-up.

Does a straight-through muffler add horsepower?

The short answer is “Yes,” with an up to 5 – 15% horsepower increase, depending on vehicle engine variables.

Will a straight-through muffler affect mileage?

No, the vehicle’s mileage should be approximately the same with or without a straight-through muffler.

How expensive is a straight muffler?

Depending on material and brand, this muffler will cost around $50-$300 and can be an inexpensive way to enhance your engine’s performance.

3. Performance exhaust muffler

Two way stainless steel pipe of a performance exhaust muffler isolated in a white background.

This muffler is popular due to utilizing many technologies to enhance engine performance and reduce engine combustion noise. The performance exhaust muffler uses a resonating chamber to tune and amplify exhaust sounds.

The sophisticated design of the performance muffler improves airflow and reduces engine back pressure to allow maximum engine horsepower. If a car passes by with an aggressive, buzzing sound, it is probably due to the vehicle using a performance muffler, often found on imported cars.

Does a performance exhaust muffler add horsepower?

Performance mufflers can add up to 10% horsepower to an engine.

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Will a performance exhaust muffler affect mileage?

The answer here is the same for most mufflers: “No.” The real reason for installing performance mufflers is increased engine performance “without” having to sacrifice fuel mileage.

How expensive is a performance exhaust muffler?

Typically, a performance muffler, depending on brand and materials, will cost around $75-$300 and is worthy of consideration.

4. Multiple baffle mufflers

A universal multiple baffle muffler isolated in a white background.

Typically installed on new factory vehicles, the multiple baffle muffler emphasizes quiet sound over performance. This type of muffler is considered a “restrictive” muffler due to reducing sound by utilizing a technique known as “pulse reflection” that manages engine pulses for maximum sound reduction.

Multiple holes are located in the silencer tube’s walls, effectively reducing the engine exhaust sound, but the tradeoff is a much more restrictive muffler. Most new factory vehicles have this muffler installed and often replaced with aftermarket mufflers for better engine performance and mileage.

Does a multiple baffled muffler add horsepower?

Multiple baffle mufflers are not designed to address horsepower but focus on muffling the sound with numerous sound-wave canceling chambers.

Will a multiple baffle muffler affect mileage?

Since multiple baffle mufflers use chambers, and many mufflers do, the engine backpressure is about the same, so mileage is not affected.

How expensive is a multiple baffle muffler?

Depending on the brand or where it is purchased, a baffled muffler should be $100 – $300.

5. Silencer inlet muffler

Close-up photo of the inlet of a new muffler for a car.

These mufflers route air straight through the pipe, bypassing traditional chambers and associated airflow buffering. The silencer inlet muffler, often known for its coffee can exhaust pipe, creates a distinctive sound while allowing an increase in horsepower.

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The straight-through airflow of the silencer inlet reduces the backpressure associated with more traditional mufflers by not being routed through a chamber. To use the silencer inlet muffler, we must confirm and ensure that the muffler will work with our vehicle’s exhaust system. 

Does a silencer inlet muffler add horsepower?

silencer inlet muffler is not designed to address horsepower and may reduce engine horsepower by 5-10%. Instead, it focuses on muffling the exhaust sound with multiple sound-wave canceling chambers.

Will a silencer inlet muffler affect mileage?

Silencer inlet mufflers may lessen back pressure, but any mileage changes should be negligible.

How expensive is a silencer inlet muffler?

Factors affecting prices include the car model and the geographical area where they are purchased, but a silencer inlet muffler should be $50 – $200.

Are mufflers an inexpensive way to improve engine horsepower?

Close up photo of titanium or steel sportive mufflers of car.

Selecting the correct muffler for your vehicle is an excellent way to improve engine horsepower. There are many reasons to change your stock muffler with an aftermarket exhaust muffler, including:

  • Improving engine horsepower by up to 5-10%. 
  • Depending on several variables, it can improve mileage with less back pressure.
  • Adding aesthetics with a “cool” factor depending on the muffler style.
  • Allowing better airflow for the engine to breathe more freely for less engine wear.

Five Top Rated mufflers for improving engine horsepower

These are some of the top-rated mufflers that can improve engine horsepower and gas mileage.

1. Heartthrob Welded Turbo Muffler

The Heartthrob muffler may improve horsepower and mileage and constructed of welded, aluminized steel.

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2. Flowmaster 50 Series Delta Flow Muffler

Made of either black aluminized steel or black stainless steel, the Flowmaster 50 Series provides excellent protection from oxidation while maximizing horsepower and gas mileage.

3. MagnaFlow Polished Stainless Steel Street Series Muffler with Tip

Close-up photo of stainless steel exhaust muffler in sport racing car.

With beautiful aesthetics and performance, including a beefy rumble sound, the MagnaFlow muffler is a top choice for performance and street racing vehicles.

4. Cherry Bomb Vortex Muffler (I had to put this one in)

With a deep, throaty growl of the Cherry Bomb muffler, it immediately announces its arrival and improves engine performance.

5. Heartthrob Velocity Muffler

Add improved horsepower without waking the neighborhood with this performance muffler designed to reduce the engine exhaust sound.