Types of Mufflers
What is a muffler?
A muffler is a part of a car's exhaust system that is designed to reduce the amount of noise that an engine produces. Performance mufflers not only seek to reduce sound levels, but to also reduce back pressure. Adding a performance muffler to your car or truck can increase your engines performance and efficiency. They can also help to reduce wear on engine components, by reducing engine heat and boosting exhaust flow. Another advantage of a performance cat-back or muffler replacement is that it improves the sound of your exhaust, so that your exhaust note is more aggressive and exiting. If you are interested in upgrading your muffler with an aftermarket unit, which type is appropriate for your application? There are many types of mufflers available and each has its benefits and drawbacks.
These mufflers are easy to spot because they are only slightly larger in diameter than the inlet / outlet diameter. Their small size lends them for use on cars that have limited clearance. As you might expect, bullet mufflers offer great flow, but little in the way of sound reduction. In fact, the flow rate is not that much different than a straight pipe. The draw back of bullet mufflers is that they are not as effective at reducing decibel levels. Bullet mufflers are offered in perforated, louvered, and chambered designs.
Perforated Bullet Mufflers
Bullet style perforated mufflers are mufflers that have a straight through flow path. As the exhaust enters the muffler, it passes through a perforated section. These holes allow sound to escape and be deadened. Due to their straight through design, if you peer into the flow path you should be able to see through to the other side. The straight through design is very good for exhaust flow, but does not do that much to quiet down the exhaust. Some bullet perforated mufflers such as the ones SLP makes use hollow space to muffle sound, while others called glasspacks are filled with fiberglass.
Louvered Bullet Mufflers
Louvered bullet mufflers, as you might expect, use louvers that protrude slightly into the exhaust path to reduce sound levels. Because the louvers block the exhaust flow slightly, louvered mufflers offer slightly less flow than perforated models. However, since the louvers trap more sound, they do tend to reduce noise levels more than perforated mufflers. When you look into a louvered pipe you should still be able to see through the muffler, because the louvers only block about 20% of the exhaust path. Another advantage of louvered mufflers is they tend to be not much thicker than the pipe itself(most of the suppression area is inside of the diameter of the pipe). Like perforated mufflers, louvered mufflers may contain fiberglass packing or just an empty void.
Chambered Bullet Mufflers
As the name suggests, a chambered bullet muffler traps sound by channeling it into chambers or crimps. This is accomplished by simply crimping a straight pipe into sound blocking chambers. No fiberglass is used. Chambered bullet designs give your car or truck a very deep tone, but they do sacrifice flow more than perforated or louvered bullet mufflers. They also offer plenty of clearance, as they are not much bigger than your exhaust piping itself. Chambered mufflers can be identified by looking for crimps on the outside of the exhaust piping.
Full Case Muffler
While they do offer great flow rates, for many street cars, bullet mufflers will not sufficiently reduce the sound of the engine. Unless you like your exhaust very loud, you are probably willing to sacrifice some exhaust flow for a muffler that keeps your exhaust tone to a more streetable level. A full case muffler will keep your exhaust system's sound level in check, while still offering significant performance gains over OEM setups. Making it a great option for high-performance street cars.
Flowmaster Case Mufflers
One of the most famous makers of full case mufflers is Flowmaster. Flowmaster case mufflers come in single and dual chamber variates. Single chambered mufflers have one chamber that wraps around the outer wall of the muffler and contains a few baffles. The dual chambered models have an inner wall that separates the muffler into two sections. You can think of the dual chambered Flowmaster as two single chambers connected end-to-end.
There are many other muffler types in the market place. Most, are variations and combinations of these principles in that they may employ one or more of the sound deadening techniques outlined in this summery. Sound levels and performance vary with type, size, and design.