Do Mufflers Increase Horsepower: Expert Findings and Analysis

Every modification should make your driving experiences enjoyable and memorable. For drivers, the noise quality should match the engine’s performance. Several drivers go for aftermarket mufflers. A question that keeps coming up is, does a muffler delete increase horsepower? 

Well, aftermarket mufflers are less restrictive than original manufacturer mufflers. That implies that drivers are likely to enjoy better performances in some quarters. But how significant is the horsepower change? Is it something that will warrant the purchase and installation of an aftermarket alternative? We offer analysis from experts who have performed muffler modifications — installing aftermarket mufflers or performing muffler delete.

Basics of engine operation

Cars have internal combustion engines. The combustion chamber is where fuel and air mix, and burn to generate power that is transmitted to the wheels through a gearbox. Once combustion is complete, the movement of the piston allows for the exhaust of gases. It pushes the waste gases out of the engine cylinder to the environment through the exhaust pipes and mufflers. Exhausts and mufflers are critical for the expulsion of combustion gases from the engine to initiate the next intake cycle.

Mufflers and Horsepower

Some drivers believe that a muffler contributes to better horsepower. Truth is, the gains are minimal. OEM mufflers could be a bit restrictive, resulting in increased back pressure on the system. When purchasing aftermarket mufflers, drivers expect them to reduce the restriction on exhaust gases and sound. 

It is a fact that aftermarket mufflers have better designs that reduce the restriction on the flow of exhaust gases and sound. As a result, the backpressure in the system decreases. 

Low back pressure improves the exhaust process and yields a slight increase in the engine horsepower. These horsepower gains are low. 

The only area where aftermarket mufflers are viable is in sound quality improvement. The different types of mufflers can alter the quality of exhaust noises. Increasing engine horsepower requires more modifications near the engine instead of the exhaust section.

Horsepower Gains From Muffler Delete

Another popular modification for the exhaust system includes the removal of the muffler from the exhaust system. The driver replaces the stock muffler with a straight pipe. The removal yields an aggressive noise that complements regular acceleration. 

Removing the muffler strips off some weight from the car. The muffler is one of the heavy components of the exhaust systems. Most drivers believe its removal boosts horsepower significantly. 

Horsepower gains are equally small with a muffler delete. A muffler delete corresponds to a boost of about 5-10 horsepower. 

Increasing Horsepower

There are different ways to boost the engine’s horsepower. The popular methods are:

  • Using cat-back exhaust systems to improve airflow and minimize backpressure.
  • Using a downpipe to redirect exhaust gases from the turbo to exhaust systems.
  • Installing a turbo (or a bigger turbo) to increase engine power.


If you are out shopping for an aftermarket muffler, it is good to lower your expectations. These units will increase horsepower by very slim margins. Most mufflers improve the sound quality of your vehicle. 


How does a muffler/muffler delete affect horsepower?

Mufflers have less impact on the horsepower of the engine. They increase engine power by small margins. They are best for sound quality management.

How do mufflers affect performance?

They decrease the backpressure of the exhaust system, increasing airflow. In return, the engine receives a slight power boost.