The humble muffler plays an important role in your vehicle’s exhaust system. It’s largely responsible for the tone of your engine and your vehicle’s overall noise level, and has some influence on vehicle performance as well. As you can imagine, choosing the wrong muffler can have a host of bad consequences, which is why it’s a good idea to understand what mufflers do and why they are so important.
The Anatomy of a Muffler
A muffler typically has one inlet, one or two outlets, and a large chamber between. The exact composition of this chamber can change from one muffler to the next:
In a straight-through muffler design, there’s a single perforated tube from one end of the muffler to the other. This tube’s perforations are designed to “trap” high frequency sound waves and route them into a layer of packing material that surrounds the tube. In a chambered or baffled muffler, the muffler has a series of angled walls that are designed to “bounce” sound waves into one another, thus canceling them out and quieting the exhaust.
In a hybrid design, a combination of both perforated tubing and baffles is used to reduce engine noise.
While muffler manufacturers like to say that one design is better than the other – and often try to support their claims by talking about things like exhaust gas flow rates or the sophisticated technology they use – the fact is that any one of these designs can be effective. Therefore, choosing a good exhaust is less about technology and more about measured performance gains.
As far as durability, mufflers are commonly made of either:
- Aluminized mild steel
- Stainless steel
Stainless steel mufflers are considered to be the “top end” muffler types as they last longer and look better. Due to their location, mufflers constructed of anything else are prone to damage and rust — especially ones that are made from mild steel. This can happen in as little as 4 years.
Different Styles of Mufflers
Thanks to the many aftermarket manufacturers like Flowmaster, Magnaflow, Borla, and Dynomax, there’s quite the selection out there. This includes lines of direct fit mufflers as well as universal mufflers that will fit on anything that has the space. Performance and noise levels also vary greatly in range. If you had to break the selection down into three categories, here’s what they look like:
These are the mufflers that the factory chose for your vehicle, or the aftermarket equivalent. The design include chambers and cylinders that cancel out sound waves to the maximum degree . Don’t expect to see any power or torque gains from these mufflers. That’s not what they’re made to do. Their purpose is to keep your vehicle quiet.
These mufflers have a more freely flowing design, boosting power and noise. This category includes the largest range of mufflers in both style and performance. It can include louvered bullet style mufflers, or mufflers that have a very “stock” appearance, but whose internals have been reconfigured.
This is an encompassing term as there are many different styles meant for “race use only” or “off road use only”, technically. Many people still use them for high horsepower applications. While the debate about this rages on, the general censuses is that vehicles with less than 500 horsepower will actually lose power with these kinds of mufflers. Typically, a race muffler is a straight-through design that allows gases to move freely in and out with only minor deflection.
So, What’s the “Right” Muffler?
With a large variety of different types of mufflers and personal preferences, finding the right muffler is a large task. While there’s a lot to be said about choosing a muffler based on how it sounds (that’s certainly a reasonable criteria), it’s most important to choose a muffler that’s designed specifically for your vehicle. Most muffler manufacturers offer vehicle-specific mufflers, and if they don’t have a muffler that’s specifically designed for your vehicle, you can choose a universal fit muffler based on your engine size.
Choosing the right muffler size is important because a muffler that’s too small or too large will negatively impact performance, and that’s the last thing any muffler buyer wants.
But sound is important as well. You don’t want to weld something up only to find that you hate the sound. Check out Youtube before ordering your muffler so you can get the best idea of how it sounds.
A self-described “car nerd,” Jason is a automotive columnist who has written for the eBay Motors blog, Motor Car Digest, as well as his own sites TundraHeadquarters.com and AccurateAutoAdvice. With an engineering degree, a full-time job in the automotive parts industry, and a decade of experience working in auto dealerships, Jason brings an interesting perspective on all things automotive.