Why Did My Exhaust Get Quieter?

By May 22, 2021Exhaust, Muffler

You are driving your car on the boulevard and you downshift a gear to make that happy downshift sound, that puts a smile on your face, but you don’t hear anything from your exhaust, or you hear some strange noise like your car is suffocating and losing power.

And you are asking yourself the question – why did  my exhaust all of a sudden go quieter?

Now let me answer your question. Your exhaust can suddenly get quieter because components like air filters, CATs or mufflers get clogged. This significantly increases back pressure which restricts the movement of sound and airflow. 

The only fix for this is to unclog the components by washing them or simply replacing them. I will discuss these in detail and by the time you are done reading, quieter exhausts will no longer surprise you.

Reasons Why Your Exhaust Can Get Quieter

Quieter exhausts can be caused by many different things, like clogging up with debris, destroyed catalytic converters, carbon build-up in your muffler, exhaust leaks, bad O2 sensors, and other issues.

Let’s look at each cause one by one.


1. Clogged Air Filter

Dirty and clogged air filters are extremely restrictive. Not much air can pass through to the engine – causing your car to suffocate and lose horsepower because there isn’t enough air to burn the fuel and create combustion.

And the other side effect of clogged air filters? Of course, Your exhaust gets quieter because your engine is not working to its full potential.

Air filters are known to clog up after a certain mile, mostly because they are replaceable – made to last around 10 thousand miles. It’s important that you replace air filters regularly or clean them if they are reusable. 

Related article: What Happens When You Have Bad Air Filters? 

Image of dirty air filter vs clean air filter

Clean Air Filter Vs Dirty Air Filter

2. Broken (Or Clogged) Catalytic Converter

Clogged catalytic converters are extremely restrictive – they don’t allow exhaust gases from passing through quickly. Increasing back pressure significantly and causing you to lose horsepower. 

As a side effect of this, your exhaust can significantly become quieter because your engine is restricted and is not able to work to its full potential. 

Catalytic converters are known to get clogged by dirt and carbon buildup. But in some rare cases, the internal components can break down and cause severe clogging. This requires a replacement. 

aftermarket high flowing catalytic converter

If the inside of a catalytic converter is damaged, it can be severely clogged.

Catalytic converters are crazy expensive, when I say crazy, I mean they go in the thousands of dollars cost of replacing them depending on the application. But it’s very important that you do because CATs is a very important component. 

Related article: What Happens If You Don’t Fix Catalytic Converter?

3. Carbon Buildup In Muffler

When a muffler is clogged by carbon buildup, it can become quite restrictive and increase backpressure. As a result, your engine is choked and cannot create as big combustion as it could.

This means, you could lose horsepower and inevitably your exhaust gets quieter because your engine is not working to its full potential. 

Carbon build-up in the muffler happens often, it’s not a strange issue. This mainly happens when the car runs rich on fuel. The air to fuel ratio is not right and the car doesn’t burn the fuel 100%.

 The main cause for this scenario is a bad O2 sensor. O2 sensors know to go bad and send bad data to the ECU and run the car poorly. This can cause not only carbon build-up in the muffler but also in the engine.

Co if you hear that your car runs weird you should connect it to a computer and check the data readings. If the O2 sensor is ok then you will look at your problem in other places, like bad coils and spark plugs. 

If the sensor is bad then you will have to replace it, and unfortunately, it doesn’t come cheap – costing around 200$.


4. You Are Getting Used To It

Quite often the case – your exhaust seems quieter because you just get used to it. 

Performance exhausts seem extremely loud when you first install it but after a couple of months, your ears get used to it and you notice it less.

Make sure it’s not just you! Get your friends or families on a test drive and ask for their feedback. Do they also think your exhaust is quieter? Most probably it’s just you!

How To Fix Quiet Exhaust

There are many ways to fix a quiet exhaust, depending on the culprit. Different problems require different solutions, and now we will see which one is for you.


Fixing Clogged Air Filter 

The best way to fix a clogged air filter is to replace it with a brand-new OEM part. I recommend OEM because unlike the cheaper alternative, these parts are approved by the manufacturer and will give you many care-free miles before they go bad.

There are also more expensive options like the K&N performance air filters – they are designed with performance in mind.

And better yet, K&N filters are reusable and can be washed. Just pop up the cover, take the filter out and give it a nice wash, just don’t forget to dry it out first before you install it on the car you don’t want water in your intake.

Related Article:  What Does A Performance Air Filter Do?

Fixing Broken (Or Clogged) Catalytic converter

Dirty and clogged CATs can be cleaned and reused. You can do this yourself or have a professional do it. Either way, you need to remove the CAT and clean the dirt away using high-pressure water. You could also rinse it with soapy water.

However, if the materials inside the catalytic converters are completely broken, then the only way to fix them is to replace the entire CAT. This will empty your pocket because CATs cost a lot to replace, 

If you live in a country where there are no strict laws, you can also straight pipe it. You can gain some horsepower and an extremely loud exhaust sound, The downside? Straight piping is illegal and is extremely bad for the environment.


Fixing Clogged Muffler

You can clean the same way as CAT – remove the muffler from the exhaust and clean the dirt away using high-pressure water. A muffler does not have any complex materials that can easily break. So you don’t have to be extremely careful.

However, a muffler shouldn’t be clogged by carbon buildup. This happens only when your car is running very rich due to faulty O2 sensors or spark plugs. Somehow there’s extra fuel coming out from the combustion chamber and they get deposited in the muffler.

The best way to fix fault O2 sensors is to replace them. It’s important you find the truly faulty one because your car is made of multiple O2 sensors.

 If this doesn’t fix the issue the car is probably misfiring, so checking out the coils and spark plugs will help you find the bad one and replace it. This will definitely fix your issue.

Does Quieter Exhaust Means Losing Horsepower?

If your exhaust suddenly becomes quieter, then you will most likely lose horsepower as well. Exhausts usually get quieter because some components are clogged (as we have seen above).

Clogged components like air filters, CATs and mufflers can restrict the flow or air or exhaust gases – causing your car combustion to be smaller and thus, losing horsepower. 

If your exhaust is by default quiet, then it doesn’t always mean that low horsepower. Only when your exhausts suddenly become quieter, then it’s a problem.

Good Ways To Make Exhaust Louder

If you are not satisfied with your current exhaust note, then there are many ways to make your exhaust louder. 

Nowadays installing a custom exhaust is the thing, there are plenty of options with many companies that create full setups of exhausts from headers to the back of the car. 

But this will also cost you some money. If you don’t want to spend a lot there are more affordable ways to make horsepower and save some money.

1. Cold Air Intake

Cold air Intake is probably one of the most popular aftermarket mods out there. The cold air intake’s purpose is to drive cold air into the engine that will improve the combustion and in addition add some horsepower.

 It is proven that it adds around 30 horsepower to your engine, also it produces a deep and enjoyable sound when you press on the gas pedal.

K&N Cold Air Intake

Cold Air Intake from K&N


2. Performance Muffler

Performance muffler, this is the cheaper variant than getting a full custom exhaust for your car, since you are going to replace only your back muffler and trust me, there are some quality options out there.

This will also not be going to hurt your wallet, since there are options for less than a 100$. 

It will add some amazing sound, but you should also take notice because in every state the law is different, and you don’t want to have a problem with the law.

Flowmaster muffler

Performance muffler from Flowmaster. (Exhaust sound is amazing with this one)

3. Straight Piping

Straight pipe, straight piping is a trend, removing all catalytic converters and mufflers. In some states, there are no laws when it comes to this and people cut their cats in order to make their car or a truck sound wild.

You can check out more ways of modifying your exhaust by following this link and read the amazing and very comprehensive article about the options available.

Cheap Ways To Make A Car Louder


Exhausts don’t usually become quieter – some performance exhausts are even expected to be louder as time passes (definitely not quieter).

If your exhausts suddenly become quieter, it’s definitely worth an inspection. Most of the time it’s just dirty and clogged components. But sometimes quieter exhausts can be an indication to a more critical issue. 

I hope this article has been useful to you. Thanks for reading till the end and till next time.

Ifandi L.

Ifandi L.

Passionate about everything mechanical. Ifandi has been involved with motorcycles and cars since the old days - in his family's auto parts shop. Want to keep in touch? Scream "STRAIGHT PIPEEEEE" at the top of your lungs and Ifandi will show up.

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