What’s your sound preference? Mild? Moderate? Aggressive? No sound at all? Maybe you want a different sound depending on what and where you’re driving? Choose an aggressive tone for your 1972 Dodge Charger that you lovingly restored and is parked in the garage, and another – shall we say – “less noticeable” tone for the Subaru Outback that’s parked in the driveway and shuttles the kids back and forth to their activities.
No matter what your harmonic preference or what you’re driving, there’s a muffler that will deliver exactly the sound you’re looking for. Welcome to the world of mufflers and sound enhancements – increasingly popular modifications that can personalize your ride.
Mufflers aren’t a new invention. The U.S. Patent Office records show that a patent for an engine muffler was awarded in 1897 to Milton and Marshall Reeves of the Reeves Pulley Company in Columbus, Ind. Mufflers in the early 1900s featured a “straight through” design that is still popular today. Essentially those early mufflers consisted of a pipe with holes, wrapped in something similar to steel wool, with the pipe passing through an outer shell. A big change to that early design occurred with a switch to a fiberglass packing material in place of the steel wool.
Contrary to the name, a muffler isn’t just muffling the sound. It’s actually destroying many of the sound waves. But let’s back up for second.
The two types of mufflers that most drivers have heard about are a chambered muffler and a straight through or “glasspack” muffler. In a chambered muffler, the sound waves generated by the engine at the end of the exhaust stroke enter the muffler and bounce around the muffler’s various chambers. As they do, they encounter friction which destroys some of the sound waves. Some of the sound waves that aren’t destroyed by friction bounce off a chamber wall and form a sound wave that’s an exact opposite, and those two sound waves cancel each other out, further reducing the noise that the vehicle produces.
In the straight-through muffler design, the sound waves pass through a straight pipe, with some of the waves being absorbed by the material surrounding the pipe, much like the earliest mufflers.
Still a third type of muffler design is a turbo style muffler in which the exhaust gases are forced into an s-shaped pattern and are peeled off and deadened by the muffler material.
Different types of mufflers yield different sounds, and that’s where personal preference and the type of vehicle enter the picture. Case in point, you’ll find more glasspacks on vintage muscle cars than you would on a custom Honda Civic.
Similarly, chambered mufflers deliver their own unique sounds depending on how many chambers they have and the chamber configuration, both of which determine which sound waves die and which escape and are heard.
The other consideration when choosing a muffler and exhaust system modification is, of course, backpressure. All those twists, turns and holes that the hot exhaust gases are forced through in the muffler slow down and restrict the gases’ migration toward the tailpipe. That restriction results in increased pressure, which forces the engine to work harder to expel the gas, which leads to a reduction in power. Less pressure equals more power, and more sound.
The muffler is just one popular modification when it comes to tweaking the exhaust system, with headers, catalytic converters and tailpipes presenting other options. Whatever you decide to modify, you’ll be in good company because exhaust system upgrades are increasingly popular and there are plenty of well-known suppliers in the game, including Walker, Flowmaster, and Magnaflow.
Begin your research by listening to as many different muffler sounds as you can, like the sound test of these eight Flowmaster mufflers that range from mild to wake-the-neighbors. Choose the one you like, and rest easy knowing you can always change up the sound if you get tired of it, or get too many complaints.
Editor’s note: When it’s time to make some noise, start with a muffler modification. Advance Auto Parts has you covered. Buy online, pick up in store, in 30 minutes.