Get Your Motor Roaring: Louder Car Without Breaking the Law!

By January 8, 2023Exhaust, Muffler, Uncategorized

Every car enthusiast loves to have a loud car that makes great exhaust sounds. However, many modifications are considered illegal and shouldn’t be done – frustrating, I know.

In this article, I’m going to tell you the legal ways to make your car louder, so you can enjoy the aggressive sound but at the same time get out of trouble. When identifying whether a sound mod is legal or not, you need to make sure the car is not producing more than 75 dB of sound.

My recommended legal ways to make your car louder is to install aftermarket mufflers  that are below the legal limit, drill holes in your muffler, install cold air intake and air filter.

When chosen correctly, these modifications are completely legal in all 50 states of the US and all around the world. I have personally installed cold air intake and flowmaster muffler on my Honda Civic without much issues.

Note: If you are looking to install new mufflers and make your car louder, then I suggest looking into other aspects to fully understand the pros and cons before committing. My other articles should help (linked below):

What Makes a Modification Illegal?

In the United States, the specific laws and regulations regarding exhaust modifications can vary from state to state. However, there are a few general principles that apply in most states:

Noise Level

Many states have laws that regulate the maximum allowable noise level for vehicles on the road, which is mostly 75 dB depending on the state. Exhaust modifications that result in vehicles exceeding the maximum allowable noise level may be considered illegal.


Most states have laws that regulate the emission of pollutants from vehicles. According to US state law, your car should have the recommended emission control devices installed. Removing a Catalytic converter or other emission control devices from the exhaust system is considered an illegal modification. 

Safety: Some exhaust modifications may be considered illegal if they pose a safety hazard to other drivers or pedestrians. For example, removing the Cat from the exhaust system alarms the risk of toxic gasses entering the car. This is considered a serious health hazard which makes it illegal.

Also Read: Does Muffler Affect Emission Test? (Aftermarket & Deleting)


Some states may require that certain exhaust modifications be certified by a recognized third party, such as the Environmental Protection Agency (EPA) or the California Air Resources Board (CARB). Modifications that are not properly certified may be considered illegal.

With the above points in mind, let’s discuss some of the best legal ways to make your car louder.

LEGAL Ways To Make Car Sound Louder

1. Install aftermarket mufflers (below 75dB)

Flowmaster super 40

Aftermarket muffler

What are aftermarket mufflers & why is it legal?

Aftermarket mufflers replace only the muffler part in your exhaust system. It will definitely make a noticeable sound difference and you can make sure it’s legal by only choosing aftermarket mufflers that are moderately loud (below 75dB – depending on your area).

Aftermarket mufflers are also safer because it will not impact any emissions and you should be passing any regular emissions test. 

Cost of aftermarket mufflers

Depending on your vehicle type, you should be able to get and install aftermarket mufflers around $200 – $400 (including labor costs) – with trucks being the most expensive and sedans being cheapest. Read my other article here to get the detailed breakdown of installing new mufflers for your vehicle: Muffler Makeover: Costs & Installation For Every Vehicle Type

My recommended legal aftermarket mufflers

If your main concern is to be legal, then you should focus on getting aftermarket mufflers that are not so loud. I recommend the Flowmaster Super 50 because it’s moderately loud and you will not be annoyed because the sound will not get into the cabin.

A lot of performance mufflers that are aggressively loud will get annoying over time because the sound seeps into the cabin and you wouldn’t be able to hold regular conversations inside the car. Super 50 will not have this issue and it should be below the sound limit.

That said, before deciding to buy and install one, I suggest reaching out to the nearest mechanic and asking him specifically about your vehicle. Some vehicles are much louder than others – making the Super 50 muffler louder as well. 

Check out this article to understand what you should look for when getting new aftermarket mufflers: Best Performance Muffler

2. Drilling holes in muffler / exhaust

Holes on muffler

What is the hack of drilling holes in mufflers & why is it legal?

Drilling holes in your (muffler or exhaust) allow the exhaust gasses to escape before going through the muffler and get silenced – which is why your car will sound louder. If you are within a tight budget, then this hack will do the job.

This hack is legal because the sound increase will not be as much (still below the legal limit) and you can ensure the holes are drilled after the catalytic converter – which ensures no impact to emission.

I have an article here which describes this topic in more detail. I also explain how and where exactly to drill the holes. Check it out: Can I Drill Holes In My Exhaust To Make It Louder?

Cost of drilling holes in muffler / exhaust

The cost of this drilling hack is below $20. You just need to buy the right size drill bit (¾ drill bit). This is of course assuming that you have the drill yourself. Otherwise, you can just borrow it from your dad or neighbors. 

You can also opt to have a mechanic do this for you, which I doubt will cost much. If I were to go to a mechanic for this hack, I wouldn’t expect to pay much – maybe some cans of beer as an appreciation. Check out my detailed article about this to see how easy it can be done.

3. Install cold air intake

K&N Cold Air Intake

What is cold air intake & why is it legal?

Cold air intake is a mod that’s supposed to focus on improving airflow to your engine for more horsepower. 

However, the side effects of installing cold air intake is a much improved car sound. And the sound from cold air intake is rather unique – it’s the sound of air rushing into your engine as you accelerate.

Cold air intake is illegal because it doesn’t make your car much louder and it definitely doesn’t change your car emission. As I said, your car will not be significantly louder, but you will have a new unique sound every time you accelerate your car.

I highly recommend installing cold air intakes (or at least look into it) if you don’t know it yet. Here’s my other articles about cold air intake that will help you understand more:

Cost of cold air intake

You can get a great cold air intake from reputable brands for below $400 (without labor costs). It’s a bit more expensive than the other legal options but it’s definitely worth it for the unique sound. 

When getting cold air intake, I recommend getting one from reputable brands like K&N because cold air intake can last a long time (5 years +) and doesn’t have to be regularly replaced like typical air filters. 

Avoid getting cheaper E-bay cold air intakes because it may not filter particles well enough, causing them to enter your engine and slowly break things down.

My recommended cold air intake

I personally recommend a K&N cold air intake – it will provide you with the unique sound that I described above. If you also want some performance gain, I recommend getting a model that’s shorter and doesn’t have as many bends.

Of course, the model really depends on your vehicle. Some vehicles have plenty of empty space in the engine bay, whereas other models don’t – but my emphasis is on as less bending as you could fit. 

If you are interested in getting cold air intake, read my article here to understand what you should look for when getting cold air intake: Best Cold Air Intake

What’s The Consequence Of Illegal Modification?

Illegal exhaust modifications can have several consequences, depending on the specific laws and regulations in your jurisdiction such as fines, vehicle impoundment, license suspension, etc.

Here are a few potential consequences that you might face if you make illegal exhaust modifications to your vehicle:

  1. Fines: Depending on the laws in your area, you could be fined for making illegal exhaust modifications to your vehicle. These fines can vary in amount and may be more or less severe depending on the severity of the modification.
  2. Vehicle impoundment: In some cases, the authorities may impound your vehicle if you are found to have made illegal exhaust modifications. Your vehicle will be seized and held until you pay the fines and any other penalties associated with the modification.
  3. License suspension or revocation: Depending on the severity of the illegal modification, you could face a suspension or revocation of your driver’s license. This means that you will not be able to legally operate a motor vehicle for a specified period of time.
  4. Increased risk of accidents: Some illegal exhaust modifications can make your vehicle louder or more prone to emitting harmful pollutants. This can increase the risk of accidents or collisions, as other drivers may not be able to hear your vehicle approaching or may be affected by the pollutants you are emitting.

Note: It’s important to note that the specific consequences you face for illegal exhaust modifications will depend on the laws and regulations in your jurisdiction. If you have any specific concerns, you should consult with a legal professional or your local Department of Motor Vehicles.

Also Read: Warranty and Insurance Worries? A Guide to Muffler Upgrades


You can totally make your car louder and still adhere to the law. There are many more ideas to legally make your car louder – even some aftermarket exhaust systems could be legal. Just make sure it’s within the sound limit and the emission is in check. 

Good luck in your journey and be sure to check out my other articles about car sounds and muffler upgrades. There are many more things to know before you commit.

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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