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What Is A Cat-Back Exhaust?

A cat back exhaust system.

Your car's exhaust plays a significant role in your performance. But did you know there is more to it than just performance? One of the most popular car modifications is the cat-back exhaust. So what is a cat-back exhaust?

A cat-back exhaust is the part of the exhaust system behind the catalytic converters. Having a cat-back exhaust installed on your car brings several benefits, such as improved sound quality, performance, and gas mileage. A cat-back system can be expensive, though, and there are different types from which to choose.

If you're considering installing a cat-back exhaust system on your car, you need to keep a few things in mind. Let's take a closer look at the performance exhaust system.

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    A cat back exhaust system.
    A cat back exhaust system.

    What Is A Cat-Back Exhaust System?

    The cat-back exhaust system is found behind the catalytic converter. Cat-back systems are found on every car, but they can be exchanged for cat-back parts from aftermarket exhaust systems. Car enthusiasts often use these modifications when customizing their cars.

    Behind the cat-back is the muffler, which is mainly responsible for sound absorption. You'll find the resonator on the opposite side, closer to the engine. While these parts are separate from the cat-back, they will also be changed when replacing your factory exhaust system.

    The catalytic converter and the exhaust manifold usually are not replaced when replacing stock exhaust systems because they are vital to complying with laws and regulations. But you can make further modifications to the exhaust system at your own risk.

    What Are The Benefits Of A Cat-Back Exhaust?

    Switching to a cat-back exhaust system can bring several benefits to your car. These are some main reasons people modify their vehicle's exhaust system.

    Does A Cat-Back Exhaust Make A Car Louder?

    One of the most significant changes that a cat-back modification brings is the sound output of the engine. The exhaust pipe is one of the main contributing factors to the car's sound.

    Installing a cat-back exhaust can give the car a more aggressive sound, which is what most of the car community is after.

    Changing the exhaust system could make the car's engine sound too loud. In this case, you could use sound-absorbing packing material in the muffler to dampen the engine's volume.

    How Much Horsepower Does Cat-Back Exhaust Add?

    Another key benefit to replacing your cat-back exhaust system is the boost in the vehicle's performance. You can sometimes add up to 10% of additional horsepower!

    Most stock exhausts are designed to detract from the vehicle's performance. Replacing stock exhausts with cat-back exhaust systems can be considered a performance upgrade that gives your engine more power.

    Cat-back exhaust systems have a larger diameter than standard mufflers. This means more free flow for air moving through the exhaust systems. With more airflow space, your engine will have a performance boost.

    A cat back exhaust system can increase fuel efficiency.
    A cat back exhaust system can increase fuel efficiency.

    How Much MPG Does A Cat-Back Exhaust Add?

    With the engine benefiting in performance and the exhaust system sounding louder, you might wonder how a cat-back exhaust system will affect your car's fuel mileage.

    A cat-back exhaust improves the engine's efficiency at the expense of a quieter muffler. As a result, a cat-back exhaust can add between 1 - 2 MPG.

    A cat-back exhaust system results in better fuel economy than a standard exhaust system. But, you might be wondering how it achieves less fuel consumption.

    When cars have cat-back exhaust systems, there is smoother exhaust gas flow. This means that the engine doesn't need to work as hard to get rid of exhaust gases exhaust fumes, thus resulting in better fuel economy.

    What's The Difference Between A Cat-Back Exhaust And A Regular Exhaust?

    Cat-back exhaust systems have a larger diameter than standard exhaust systems. This allows for better exhaust flow which provides a wide range of benefits. From the outside, you'll notice that cat-back systems have bigger exhaust pipes than standard exhaust tips.

    In addition to the bigger exhaust tips, the cat-back system will also have larger diameter piping. Cat-back systems are usually made from aluminized steel which also provides corrosion resistance.

    Aside from a performance boost, you can also expect better fuel economy and a louder, more impressive engine noise!

    Custom cat back exhaust are often installed by people looking to improve the performace of their sports cars.
    Custom cat back exhaust are often installed by people looking to improve the performace of their sports cars.

    Is A Cat-Back Louder Than A Muffler Delete?

    While a cat-back system will make your car louder, it's not as loud as a muffler delete. Muffler delete exhaust systems are significantly louder, cheaper; although some cat-back systems technically include a muffler delete as part of the package.

    You can also fit different types of mufflers for the exhaust system. You can choose the system that suits you best, between straight-through mufflers, glass pack mufflers, and mufflers with perforated baffles.

    Different Types of Cat-Back Exhaust Systems

    There are several types of cat-back systems to choose from, including a single exhaust, dual exhaust, and dual exit (a modification of the single exhaust).

    Most people prefer the dual exhaust for the sportier look, increased performance, and unique sound. A dual exhaust system has two exhaust tips compared to just one on the single exhaust system.

    You can also find other modifications such as mid-pipe, X-pipe, Y-pipe, and H-pipe systems. As you can see, the customization options for your entire exhaust system are endless.

    Is Cat-Back Louder Than Straight Pipe?

    Cars with a straight pipe exhaust are the loudest. In addition, vehicles with a straight pipe exhaust modification create more pollutants because the catalytic converter is removed.

    One of the benefits of a cat-back is that it still has the catalytic converter attached to the exhaust pipe, which cleans the exhaust gases.

    Will A Cat-Back Exhaust Pass Inspection?

    You will still pass any inspections with a cat-back system installed on your car. That's because the original exhaust's catalytic converter (CAT) will still be fitted to your vehicle.

    The CAT is the most important system component for passing inspection because it's vital in cleaning exhaust fumes and removing any pollutants and toxic gases before expelling them into the environment.

    However, you still need to be careful when installing any aftermarket exhaust systems onto your vehicle, even if it is a cat-back system. As mentioned, there are different types, so double-check the legality of the component fitted to your car.


    You might have heard a lot of people talking about vehicle modifications and wondered: “what is a cat-back exhaust?” Hopefully, this article has answered your question.

    The cat-back is the section of the exhaust behind the catalytic converter. You can replace this section of the exhaust system with an aftermarket version which will make your car louder and more fuel efficient and give your car additional horsepower.