Do After-Market Exhaust Systems Really Work?

In a word, yes. However, there’s a little bit more to it than that. If you don’t understand HOW upgrading your exhaust system or muffler(s) adds power, you could end up buying a system that you’re really not happy with. Here’s what you need to know:

How After-Market Exhaust Systems Add Power

98% of new vehicles come with exhaust systems that are fairly restrictive. Unless you’ve purchased a dedicated sports car like a Corvette, Porsche, or Ferrari, the auto manfacturer has sold you a car with a limited exhaust system.

Are you driving a dedicated sportscar? No? Then your exhaust system is probably restrictive. Image copyright John Perser.

Why do manufacturers do this? Because restrictive exhausts are quiet and inexpensive. Automakers strive to make a great product, but they often cut corners in places where most consumers will never notice. The factory exhaust system is one of these places.

After-market exhaust systems add power because:

• They are often made with superior quality materials
• Better airflow
• They are louder

1. Better Materials

Borla exhaust systems, for example, use 201 or 304 series stainless steel for pipes and mufflers which is thicker, stronger, and more resistant to corrosion than just about any factory exhaust system. Thicker and stronger steel also doesn’t resonate as easily, which reduces noise and eliminates “drone” without impacting performance.

Flowmaster and Magnaflow use upgraded materials in their mufflers that improve sound-deadening without resorting to restrictive exhaust path designs like most factory mufflers.

2. Better Airflow

In many ways, the modern engine is really just a big pump. You put air and fuel in, and you get exhaust and horsepower out. The more air and fuel you can put it, the more horsepower you’ll have. Therefore, if you make your exhaust system flow better, your “pump” can work better. However, there is a catch – larger systems aren’t always better. See After-Market Exhausts Can Disrupt Your Car’s Power Curve for more info.

3. Louder

The cheapest and easiest way to make an exhaust system quiet is to completely disrupt the flow of exhaust gases. Most factory mufflers use a very basic design that essentially forces all the exhaust gases to find their own way out – sort of like stuffing an ice cream cone until something breaks.

The type of design illustrated above is the cheapest, easiest, and most common way to make an exhaust system quiet. Of course, disrupting exhaust gas so dramatically causes a flow restriction. Because a lot of new car customers don’t want a car with a loud exhaust, most new cars come with this type of setup. When you go with an after-market system, you get more noise, but you also get more power.