Exhaust System

What Is A Cat Back Exhaust Systems?

Mike Cross
Updated Aug 25, 2021
What Is A Cat Back Exhaust Systems

Replacing an exhaust system or some of its components seems like a simple and straightforward job. You just take your car to the workshop where they will replace broken mufflers or pipes. This is true if you are keeping your car stock. The situation is totally different if you want to tune-up your exhaust to improve performance, sound or looks of your car.

You might think it all comes down to replacing an end muffler with aftermarket one. But dig a bit deeper into this subject, and you will come across things such as mufflers, resonators, pipe diameters, back pressure and so on. You might conclude that exhaust system is not that simple at all. Replace one part while leaving others stock, and you might end upsetting the exhaust balance. A last thing you want is loss of power or exhaust that sounds like an old truck. How to make sure this will not happen to you? Well, this is where cat back exhaust systems come into play.

What Is A Cat Back Exhaust Systems
What Is A Cat Back Exhaust Systems

What is a cat back exhaust systems?


Your engine has an exhaust manifold, which is followed by a catalytic converter. Everything past the catalytic converter and all the way to the exhaust tail pipe tips is called a cat-back. This always refers to an aftermarket performance systems. In most applications, cat back systems have:

  • Resonator
  • Connecting pipes
  • Muffler with exhaust tip

In your exhaust system, resonator is first 'in line of fire'. This is where you have a chance for increasing your engine power and throttle response. Majority of stock systems use chambered resonators. These are great for noise reduction, but they increase exhaust back pressure. Replacing these with straight through resonators will increase the exhaust speed and flow. Your exhaust will be louder, but this will be OK as long as there is no exhaust drone. Choosing a resonator with correct length and diameter is crucial for avoiding it.

When it comes to pipes, there are two things to consider: diameter and bending. It is common to use a bit larger pipe diameter. This will increase exhaust flow rate, resulting in more power from your engine. Yet, significantly larger pipe diameter will have negative impact on your performance. Also, all bends should be mandrel made, as this will ensure continuous exhaust flow.

Mufflers are a final element of your exhaust system and have the biggest impact on the overall exhaust note. It has least effect on the exhaust flow and back pressure. This means that you can choose one that will bring the noise down, without affecting the engine power. Also, exhaust tips are a part of the exhaust system that is always visible. Right exhaust tip will bring up the visual appearance of your car. You can choose from mufflers with a single or dual exists, and with various tip shapes for the best result.


Stock systems are usually made from aluminized steel. Most aftermarket cat back exhaust systems are made from stainless steel. This has many advantages. It is durable, so most manufacturers give 10+ years to life-long warranty. It gives a nice and deep exhaust note. And polished finish will make your exhaust system look stunning.

Either fiberglass or stainless steel mesh is used for sound deadening. Glasspacks, which are quite cheap, use fiberglass. Their downside is a shorter life-span, because the fiberglass burns out over the time. Go for the resonator with stainless steel mesh if you want your resonator to last long.


On V6 or V8 engines, X-pipes or H-pipes can be used instead of resonators. In this case, noise and drone cancelation are achieved by their careful design and positioning.

When buying a cat back system, make sure that it has hangers welded on same places as stock system. Also check if a selected cat back system comes with new bolts, nuts and exhaust gaskets.


If you are planning on tuning up an exhaust system on your car, make sure you have chosen a correct exhaust component. You don't want to upset the exhaust flow balance, as this would result in power loss and nasty exhaust sound.

In the end, a cat back systems is the best way to go. They are tailored specifically for your car and engine type by professionals with decades of expertise. This is a guarantee that your car will achieve better engine performance, sound sportier and look more attractive. And, as they are 'bolt-on', you will be able to can fit it yourself.

Mike Cross
Life is too short to drive with stock audio

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