GMC Mufflers

FAQs—GMC Muffler

1. What’s the difference between a stainless steel and an aluminized muffler?

The main difference between the stainless steel muffler and the aluminized muffler is the outer shell of the unit. Stainless steel mufflers are fitted with a polished stainless steel shell and have a stainless construction. Aluminized mufflers, on the other hand, have stainless internal components and necks but have an aluminized outer shell.

Stainless steel mufflers are often recommended than aluminized mufflers because they are more durable than aluminum and are less susceptible to corrosion. Most aluminized mufflers sold in the market nowadays have a rust resistant coating as well.

2. What do “single exhaust” and “dual exhaust” mean?

In a single exhaust system, the primary exhaust tubes lead to a single collector and muffler to draw the gases out. Cheap and fairly efficient, this is the most common muffler configuration in most GMC vehicles. Dual exhaust systems, on the other hand, keep the exhaust streaming to two cylinder banks and out from a pair of muffler. This configuration allows increased flow of exhaust gases from the engine to the tailpipe.

3. Are performance mufflers legal to use?

The legality of aftermarket performance mufflers depends mainly on the type of muffler you want to use and the state where you live. Many performance mufflers sold in the market today comply with federal regulations, but they may not meet the guidelines of individual states. Mufflers that are designed to modify the sound of the exhaust must also comply with sound level limits of various states. Make sure to check your state laws to see if the muffler you are planning to install on your vehicle meets all of their guidelines.

4. Do mufflers have an initial break-in period?

Mufflers, particularly in the case of aftermarket mufflers, typically have a break-in period of a few hundred miles until they reach a slightly louder and deeper sound. During this break-in period, the exhaust may also temporarily expel white smoke and emit a slight odor caused by the thermal grease used during the pipe bending process being burned off by the hot exhaust gases.

5. Does a bigger muffler pipe mean more engine power?

Contrary to rumors, a muffler with a bigger diameter exhaust does not equate to additional power. In fact, having a muffler with a big pipe may cause an imbalance in back pressure reduction, exhaust velocity, and other variables that affect the efficiency and effectiveness of the exhaust system of your vehicle.

Rather than focusing on getting a muffler with a bigger pipe, it is better to get a muffler with a more efficient pipe. The muffler must have a balanced design in order to boost the car’s maximum engine output, exhaust gas velocity, and sound levels. This is why it is very important to get the proper size of piping in order to cut down the backpressure from the exhaust while at the same time maintaining thermal efficiency.

6. What causes discoloration in the muffler tips?

An inevitable condition no matter what type of muffler you have, discoloration is caused by the leftover residue from the compounds used to polish the surface of the muffler and the muffler tip. This compound, which is often made up of various metals ground into fine particles, becomes embedded in the microscopic pores of the tip. And over time, the particulates from the compound oxidize and change color from the heat of the exhaust, resulting in a yellow or gold tint. This discoloration is further aggravated by very high temperature exhaust gases from modified exhaust systems or by driving in especially harsh climates.

The type of muffler tip you have may also influence the severity of the discoloration. A single-walled muffler, for example, lacks a thermal barrier and thus more exposed to heat that accelerates oxidization.

However, despite its unsightly appearance, discoloration in the various parts of the muffler is not proven to have an adverse effect on the performance of the engine and exhaust system. In fact, discoloration in the muffler tips and other muffler components can be removed via regular cleaning with a wheel cleaner. Investing in a double-walled muffler tip can also reduce discoloration as it has better insulation against the heat of the exhaust gases.

7. What are the advantages of a custom muffler?

While they are more expensive than a standard OEM muffler, customized mufflers offer power and efficiency as they are specifically tailored for your GMC model. These aftermarket mufflers can provide a more efficient path for gases to escape your engine, allowing it to “breathe” better and allow spent fuel and air exit the combustion chambers faster. A high quality custom muffler can also create a deeper, more aggressive note from exhaust particularly when accelerating.