When people think about mufflers and their purpose, the general consensus is that their function on your car is to make your engine noise quieter. While this is true, their designs are quite complicated, as you don’t want your car to develop too much or too little back pressure, which will lead to decreased performance. Our performance shop pros sat down to talk to us about why you should never skimp on a high-quality muffler.
How Do Mufflers Work?
While mufflers do vary in their design, the basic concept is always the same. Your car’s muffler is rectangular shaped box towards the rear of the car in front of the exhaust tips. If we cut a muffler open, we will be presented with two sections of exhaust pipe on either end of the muffler. Between these two pipes there are a series of resonating chambers and baffles where sound waves travel into and are then either trapped and resonated to a lower frequency, or are absorbed by various insulation, but still have enough paths for the exhaust gas to flow through. If you can’t quite imagine what the inside of a muffler looks like, Wikipedia has uploaded a picture of a muffler that has been cut open for your reference.
Mufflers and Performance
There is a common misconception that in order to get the best performance out of your exhaust, you need to cut your muffler off. This is wrong simply because removing your muffler may not improve the velocity at which exhaust gas travels out of the engine. For the best performance your car’s engine needs to be able to breathe. Much like any living animal, your car pulls in fresh air and needs to dispose of exhaust gas as fast as possible.
When you cut your muffler off and replace it with a piece of exhaust tubing, you can inadvertently change the pressure in your exhaust system. Many people believe that decreasing the pressure in your exhaust will increase your performance, but the science behind exhaust flow is a little counterintuitive. If exhaust gases are under too much pressure, your engine cannot get rid of the exhaust gases as quickly as it needs to and can begin to suffocate the engine. On the other hand, too little exhaust pressure reduces the velocity at which at exhaust gas can travel, leading to this gas staying in the exhaust for longer, and suffocating your engine.
Deleting your muffler also cheapens the experience of driving your car as the droning sounds of a muffler-less engine fills the cabin of the car, as well as turning your engines once guttural roar, into high-frequency squeal that nobody will enjoy.
Performance Mufflers and Valves
There are multiple benefits of a performance exhaust and muffler; they are designed to have the same performance benefit of a straight pipe exhaust, while keeping the luxury of a quiet exhaust. High performance exhausts do away with the traditional muffler with resonating chambers and replaces it with single straight pipe. On this single straight pipe, there are holes cut into the pipe, which resembles a heat guard on a barrel of a machine gun. Surrounding this pipe is a large amount of sound-deadening material, which varies from rough fiberglass to aluminum meshing. This allows for exhaust gases to travel through the muffler at peak velocity, while sound waves can escape through the holes in the pipe and be absorbed by the sound-deadening materials.
On some high-end sports cars, the exhaust features valves that sit just before the muffler. The valves are there to direct the flow of the exhaust gases, either into the muffler to reduce sound, or to bypass the muffler entirely to give the car the loud free flowing exhaust note. Often these valves are linked to the cars ECU, so they only bypass the muffler when the car is in sport mode, or the car is revved pass a certain rpm. Valve exhausts are becoming more and more popular as they give the driver the best of both worlds when it comes to exhaust sounds.
If you’ve decided to change your car’s muffler, there are several aftermarket upgrades you can do to your exhaust to get the most out of your exhaust system and muffler. Whether you’re looking for a custom exhaust system, or a full drop in exhaust, look no further than Foreign Affairs Motorsport, South Florida’s Premier European Auto Repair, Performance & Race Facility Since 1978.