Muffler Delete On Diesel: Does It Work? (Horsepower & Sound)

By February 20, 2022Does It Add HP?, Exhaust, Muffler

Muffler delete in the diesel engine’s exhaust system is basically done for the sound and performance. The purpose of deleting the muffler from the diesel engine can vary person to person. But the majority of the people delete mufflers to show more aggressive characteristics to their vehicle.

Different components of the exhaust system of a typical diesel engine are catalytic converter, particulate filter and muffler.

Many people in my circle use diesel trucks and almost all of them have deleted the mufflers or straight-piped their vehicles. In this blog we are going to discuss the pros and cons of muffler delete in a diesel system.

What is a muffler delete?

Muffler delete means when you remove the muffler from the exhaust system and install a straight pipe in place of the muffler. This is basically done to enhance the engine sound of the vehicle.

Muffler absorbs the sound waves coming from the engine and makes the vehicle sound decent so when you remove the muffler you basically remove the filter that is making your car soundless. This makes the engine sound louder and sometimes improves performance.


RELATED ARTICLE: Muffler Delete Vs Resonator Delete: Sound, Power & Cost

Does a diesel engine need mufflers?

Diesel engines run fine without mufflers. Diesel engines can even run without an exhaust system because they are low revving engines and are made for torque purpose.

Diesel engines are purely made for the torque and the rev low as compared to the gasoline engines. If noise is not an issue to you, the diesel engine will run fine without a muffler.

There are other components of the exhaust system of the diesel engine that are important for the functioning of the engine or to pass the emission standards of the states but as far as the muffler is concerned it is not that much important to have it in diesel engine 

Can you remove a muffler in a Diesel engine?

Removing the muffler on any vehicle entirely depends on the state law and inspection rules varying from country to country. Many state laws do not allow muffler delete because it does not match the emission control laws of the state.

There are different laws around the globe related to muffler delete so you must check the laws or emission control standards before removing the muffler. If you keep the other components intact and only remove the muffler you may not face that much problem as it will not produce significant sound but it may fail in the vehicle inspection tests.

Some vehicles with low displacement may not need mufflers as these do not produce that much sound hence these are made without mufflers from the factory. So, you cannot make these sounds louder and have to bear it as it is.

What does muffler delete do to a Diesel engine?

Muffler delete in diesel engines does not change anything significantly. Diesel engine is a low revving engine so deleting the muffler has less to no impact on the engine.

Diesel engine is made for the torque purpose and it does not produce that much exhaust gas pressure that you need a muffler or resonator to absorb the sound frequencies. Even if you do not use any component in the exhaust system, the diesel engine works fine.

Muffler delete in the turbo charged diesel engine may cause some changes that are significant for example making the vehicle sound loud because the flow of gasses is different in turbo charged diesel engines as compared to a naturally aspirated diesel engine.

Diesel engine has other exhaust components that are necessary for the function of the engine, for example a catalytic converter. Catalytic converter makes the engine performance up to the mark and ensures a clean environment. If the catalytic converter is removed you may face problems regarding air fuel mixture ratio or may not fulfill the emission control standards of your country.

RELATED ARTICLE: Muffler Delete Vs Straight Pipe: Horsepower, Mileage & Damages

What is the main use of a muffler in a diesel engine?

Main use of the muffler in the diesel engine is to damp the sound of the engine. Every gasoline engine needs a muffler to damp the sound produced from the burning of air fuel mixture in the cylinder.

The turbo charged diesel engine makes the exhaust gasses pass the exhaust system with a relatively higher pressure than the non turbo charged engine so you may need the muffler for these engines. But if your vehicle has a non turbo engine you may not need the muffler for these engines.

Apart from the turbo engines the non turbo engine may need a muffler because some engines produce sound of specific frequency that needs to be absorbed. So, these engines also require mufflers to absorb and dampen these kinds of frequencies.

Other than dampening sound the muffler does not perform any job in the diesel engine that’s why diesel engines with smaller displacement may not need a muffler at all because the sound produced by them is very low and it can’t be damped further. But for the turbo engine it is necessary to have the muffler installed in the exhaust system. 

Does the muffler delete from the diesel engine make it louder?

Muffler delete on the diesel engine has very little impact on the sound of the engine. It does not make it louder like a gasoline engine after a muffler delete.

Diesel engines do not produce that much loud noise just like the gasoline engines do because the gasoline engines are high revving engines as compared to the diesel engines. So, the sound produced by diesel engines as a result of the burning of the air fuel mixture is very less than that of the gasoline engine. This is the reason why gasoline engines have more components in the exhaust system as compared to the diesel engine.

Diesel engines without the muffler may sound a little loud but not that loud as you might expect it to be. Sometimes the difference is not even noticeable with or without a muffler depending on the displacement of the engine.

The sound gets louder when the engine is turbo charged and you delete the muffler from the exhaust system because the turbo charged engine is pushing the gasses at a slightly higher rate due to the turbo which creates a pressure in the exhaust system and muffler delete makes it sound loud.

Does the horsepower increase by deleting the muffler?

Horsepower does not increase by deleting the muffler on the diesel engine. Muffler is not causing any obstruction to the flow of exhaust gasses so muffler delete has no effect on the horsepower

It is a misconception that the horsepower of the engine increases when you delete muffler but it’s not true for the diesel engine as the back pressure of the exhaust gasses is very low and is not significant enough to limit the engine’s performance so even if you remove the muffler, it has no impact on the horsepower.

Some diesel engines even come without a muffler from the factory so which means the muffler does not have an impact on the performance of the engine and you do not need to delete the muffler only for the performance purpose because it will not work on the diesel engine

You may see a slight difference in the performance of the vehicle after muffler delete if the vehicle is turbo charged because the turbo charged engine creates a little high pressure in the exhaust system and gasses flow at higher rate so it makes gasses flow smooth if the muffler is deleted. But this improvement in the performance is not significant enough and sometimes not even noticeable.

RELATED ARTICLE: Do Mufflers Increase Horsepower: An Expert Weighs In

Does the Diesel exhaust have a muffler?

Diesel engine’s exhaust system comes with a muffler. The purpose of which is noise reduction. Diesel engine has less sound as compared to the gasoline engine but the muffler is still there in the exhaust system of a diesel engine.

Almost every internal combustion engine needs a muffler in the exhaust system because every engine produces noise during the combustion that needs to be reduced. Usually, the sound of the diesel engine is not that loud but there is sound of certain frequencies that must be reduced for the better sounding of the vehicle and it is done by installing a muffler in the exhaust system of the vehicle.

The turbo charged diesel engines mostly produce greater sound than the naturally aspirated diesel engines so the muffler in the exhaust system is necessary for the sound dampening.

Is it harmful to remove the muffler in a Diesel engine?

There is no harm in deleting the muffler from the diesel engine exhaust system. As the muffler is only for the sound dampening purpose so it’s not harmful for the engine health.

Many diesel engines work well even without any exhaust system because the backflow of the exhaust gasses does not exert that much pressure on the engine and if you straight pipe the engine, it works fine.

Diesel engines are low revving engines and the noise and gasses produced as result of the running engine are very low as compared to the gasoline engine of the same displacement. So, the diesel engines require less components in their exhaust system as compared to the gasoline engine. 

From the above discussion it is clear that keeping the exhaust system of the diesel engine stock or deleting the muffler does not affect the performance and has no harm on the engine’s health.

Before deleting the muffler, you must check the laws about modifying exhaust system in your state because if it’s illegal to remove muffler then you should not do it because your vehicle will not fulfils the emission control standards and you will be in trouble for this and your vehicle may fail in the yearly inspection tests. So, it is necessary to check laws before doing any modifications to the exhaust system of the vehicle.


From the discussion and questions answered it is clear that muffler delete from the exhaust system of the diesel engine has no to less impact. If you want to increase the sound of the diesel engine then muffler delete is not the solution like in the gasoline engine. Muffler delete may be helpful to increase the sound of the turbo charged diesel engine because of the high flow of the exhaust gasses from the exhaust system. But for the naturally aspirated diesel engine, muffler delete is not the solution to increase sound. As it has no impact on the power of the diesel engine so it does not matter if you remove it or keep using, it will not increase or decrease the power of the engine.

As far as the health of the engine is concerned it is evident that diesel engines do not require any specific exhaust system for the optimum function, they can run properly even without the exhaust system so keeping or removing the muffler from the exhaust system will have no negative impact on the health of the diesel engine.

Before removing the muffler of the diesel engine, you must be aware of the consequences of the laws as it may cause trouble for you. Every state has different emission control standards that must be fulfilled in order to pass the yearly inspection so these requirements should be fulfilled according to the laws of your country

Chai WJ.

Chai WJ.

I am a car enthusiast and a passionate rider who loves to discover new places. Since the pandemic, I can't go to places and I started to blog and share information that I learned. I'm not easily distracted, I just... OMG, do I hear a Supra?

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