A Beginner's Guide to Aftermarket Exhaust System Components

Author: CC

Mar. 07, 2024

Automobiles & Motorcycles

Let’s break down the anatomy of an exhaust system—each component, what it does, and why it matters.

Remember the first time you talked anatomy in the classroom? Yeah—well, this discussion of anatomy probably isn’t going to be nearly as eye-opening, exhilarating, frightening, or embarrassing (or all of the above) as that conversation. But for aspiring hot rodders, the “exhaust talk” is just as important.

We couldn’t find a creepy old gym teacher to teach our exhaust anatomy lesson, but hopefully we’ll do a better job anyway.

Why Choose Aftermarket Exhaust Components?

The factory exhaust system on your vehicle is designed to muffle sound as much as possible. This also means it restricts the flow of exhaust gases out of your engine, creating what’s called backpressure. While most engines require some backpressure to operate properly, it also robs power. Essentially, the engine has to use some of the power it generates to cram exhaust gases out of the tailpipe instead of using that power to drive the vehicle.

If you’d like to steal some of that power back, you can replace that stock exhaust with less-restrictive performance exhaust components. In some upcoming posts, we’ll show you how to choose the right components—exhaust kits, headers, mufflers, etc.—for your vehicle. But let’s start with a quick review of exhaust systems and components and some of the upgrade options that are available.

Headers/Exhaust Manifolds

The first exhaust components to handle spent exhaust gases from your engine, headers (also called exhaust manifolds in stock form) are bolted to the cylinder heads and scavenge exhaust gases from the combustion chambers.

Aftermarket headers are typically mandrel-bent to reduce exhaust restriction, allowing the exhaust gas to move freely from the engine. This reduces power-robbing backpressure and helps build up enough exhaust flow velocity to create energy pulses that actually pull, or scavenge, spent gases from the engine.

Headers are available in full-length and “shorty” dimensions and come in multiple configurations, including Tri-Y and 4-into-1. We’ll talk more about choosing the right design for your ride in a later post.


Also called head pipes, downpipes simply link the headers to the mufflers. Between these two points, a downpipe is often interrupted by the catalytic converter, depending on the application.

Catalytic Converter

If your vehicle was produced after 1975, chances are good that it came from the factory-equipped with a catalytic converter (also known as a “cat”). Unlike a muffler whose primary function is to lessen exhaust noise, a catalytic converter employs some serious science to reduce the amount of harmful emissions your vehicle releases into the air.

Why do you need a catalytic converter? It’s the law. State and federal regulations require you to have one of these air fresheners if you’re traveling on public roads.

The way they work is pretty simple: exhaust gases flow through two ceramic honeycombs contained in the cat, each of which is usually coated with a combination of precious metals. When those exhaust gases come into contact with the coating, a chemical reaction is initiated that converts your vehicle’s emissions to nitrogen, carbon dioxide, oxygen, and water before releasing them into the atmosphere.


One of the most recognizable components of the exhaust system, the muffler is responsible for exhaust noise reduction. While the job description of a muffler sounds simple, the way in which a muffler performs its main task is varied and complicated.

Depending on the style, a muffler uses some combination of baffles, chambers, perforated tubes, and/or sound deadening material to achieve this goal. Muffler manufacturers configure these components in different ways to produce different exhaust tones. Ideally, an aftermarket muffler will provide a good performance exhaust tone without creating too much power-stealing backpressure.

Crossover Pipes

Crossover pipes are designed to balance the exhaust flow on a dual exhaust system. Typically installed near the headers, crossover pipes reduce uneven exhaust flow from the two banks of engine cylinders by giving exhaust pulses an avenue to travel between the two sides of the dual exhaust system. This reduces backpressure by preventing an exhaust build-up on either side of the system.

The two most common types of crossover pipes are X-pipes and H-pipes. As their names suggest, X-pipes are shaped like the letter “X,” and H-pipes look similar to an “H.”


The tailpipe is often the last piece of the exhaust system puzzle. It runs from the muffler to the back or side of your vehicle. Many aftermarket manufacturers will finish off their tailpipes with a chrome exhaust tip or polished exhaust tip. You can also buy exhaust tips separately in your choice of finishes or shapes.

Now that you know the basic anatomy of an automotive exhaust system, we’ll help you get to second base by showing you how to choose the right exhaust for your ride.

A lot of people consider cars more than just a means of transport. For many, cars show their personality. This is why so many people upgrade and modify their cars to their liking. Because of this, the aftermarket is full of modifications such as suspensions, wheels, tires, body kits, and much more.

In this guide, we’ll cover one of the underrated modifications done to cars - the after market exhaust system. You’ll find out what an aftermarket exhaust system is, what are the exhaust system parts, and why you should choose an aftermarket exhaust system compared to a stock exhaust system.

What is an Aftermarket Exhaust System?

An aftermarket exhaust system isn’t just a muffler or an exhaust tip. It includes exhaust system parts such as the exhaust manifold, pipes, mufflers, catalytic converters, and everything between the engine and the exhaust tip.

An aftermarket exhaust system is different from a stock system. Although it does the same job, aftermarket exhausts usually provide better exhaust flow, thus increasing the car’s performance abilities, and altering its sound. The sound itself is a big enough reason for many people to consider changing certain parts of a exhaust system, but the biggest reason for using an aftermarket exhaust in your car is to let it breathe better.

Key exhaust system parts include:

  • Exhaust manifold
  • Oxygen sensors
  • Catalytic converter
  • Resonator
  • Exhaust pipes
  • Mufflers
  • Tailpipe

Depending on the year, make, and model of your car, certain parts from the list may be absent from your car, but most commonly, you’ll find these parts under your car.

Aftermarket Exhaust Systems vs Stock Exhaust Systems

When it comes to the difference between an aftermarket exhaust and a stock exhaust system, the exhaust system parts are usually the same, however, they’re made differently to improve exhaust flow.

Stock exhaust systems are made to reduce as much noise as possible coming from a car’s exhaust. Without an exhaust system, a car, no matter how large or small the engine might be, would be unbearable to drive from the noise it would emit. The stock exhaust system reduces this sound as much as possible, but by doing so, it also restricts the exhaust flow, limiting the total power output of the engine. 

Aftermarket exhausts, on the other hand, focus on providing better flow throughout the entire system. Noise-canceling isn’t the main thing with aftermarket exhaust systems, which is why they’re usually louder but have a specific rumble they emit that enthusiasts usually enjoy hearing.

The key differences between stock and aftermarket exhaust systems are:

  • Pipe diameter
  • Bending technique
  • Materials used in manufacturing

The pipe diameter is a key difference because a larger diameter used in aftermarket exhaust systems allows more air to flow through them. 

The bending technique with most stock exhausts is called crush bending. It’s the most affordable technique, which is why most car manufacturers still use it, however, this technique lessens the diameter of the tubing on the bend, and decreases the performance capabilities of a car. In aftermarket exhaust systems, the bending technique used is called mandrel bending which doesn’t restrict flow and doesn’t change the diameter of the tubes. 

Lastly, aftermarket exhaust systems are made from higher quality materials than stock exhaust systems. The material used in manufacturing parts of a exhaust system directly affects its performance capabilities. This is why stainless steel is most commonly used for performance and aftermarket exhaust systems. Because of the unrestricted flow, installing a performance exhaust can also improve fuel economy.

Why You Should Choose an Aftermarket Exhaust System

Although aftermarket exhaust systems cost more than stock ones, there are a couple of advantages you should consider.

Compared to stock parts of an exhaust system, aftermarket parts are usually made from higher quality materials such as stainless steel. The materials used are commonly resistant to corrosion, and heat. Better materials mean more longevity for the parts, and looking at it in the long run, aftermarket exhaust systems are a worthy investment compared to stock parts that are made from lower-quality materials. 

Another reason for choosing aftermarket exhaust system parts is the sound they can produce. As we already mentioned, stock exhaust systems reduce the noise by limiting exhaust flow, but when the pipe diameter is larger, a deeper, more sporty sound is emitted from the exhaust. Depending on the muffler, the noise difference can be minimal, but with better flow altogether.

Even adding a few aftermarket exhaust system parts can add a few horsepower and increase torque, which is more noticeable if you already modified the engine in any way.

Lastly, an aftermarket exhaust can increase fuel economy, which may not be a significant difference right away, but after a few thousand miles, you’ll notice a few extra dollars in your wallet.

How To Choose an Aftermarket Exhaust System

Before choosing an aftermarket exhaust system for your car, you should gather enough information about what kind of exhaust system you need. Some cars have a single exhaust, some have dual exhausts. Choosing the material is also a key factor, not just because it affects how long the exhaust is going to last, but the price as well. The most expensive option is stainless steel, however, this material is resistant to corrosion, so if you live in a snowy or rainy area, this should be your top choice.

Another thing to consider is whether you need a full exhaust system or a partial one. One of the more popular options is choosing a catback exhaust which starts right after the catalytic converter. It’s easy to install and doesn’t cost as much as a full exhaust system. It will still give you a noticeable performance increase and will give your car the sound to turn heads.

Exhaust systems are an important component in any car, and whether you choose an aftermarket system, or a stock one, you can find a wide variety of exhaust parts at JEGS. You’ll find brands such as Mishimoto, JEGS, Borla, Flowtech, and many others that cover a variety of makes and models.

A Beginner's Guide to Aftermarket Exhaust System Components

Aftermarket Exhaust Systems & Parts - Beginner's Guide




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