Can You Make A Glasspack Quieter?

can you make a glasspack quieter

A glasspack is a type of muffler found in automobiles where the exhaust gas passes straight through the center of the muffler. While it is an essential part of the muffler, many people have complaints about the volume of their glasspack. This dilemma causes people to wonder if there are any alternative solutions to fix their loud glasspack.

Can you make a glasspack quieter? It is possible to make a glasspack quieter. The main factor in changing the volume of your glasspack is to replace it with a longer one. Glasspacks are loud because of a variety of factors such as size, age, and shape.

Making your glasspack quieter is a simple process that does not involve many steps. There are a few different ways to think about changing the volume of your glasspack. After reading the instructions below your questions about glasspacks and the volume of them should be clear.

Can You Make a Glasspack Quieter?

The longer the glasspack, the better when it comes to volume control. Some glasspacks are about six to eight inches long which would be considered a medium size for a glasspack. At their longest, glasspacks can be anywhere from 22 inches to 34 inches.

You have to make sure that the glasspack you are buying will suit your automobiles, as many long glasspacks (22-34 inches) were made for older vehicles produced from the 1960’s to the 1980’s. The length of the glasspack is the ultimate determining factor when it comes to noise in your vehicle.

Another way to make your glasspack quieter is to replace it because glasspacks tend to get louder over time. This is not as effective as changing the length, but it is worth trying if you don’t feel comfortable with changing the size of your glasspack. Replacing your glasspack with a new one that is the same size but newer works best with older vehicles.

While resonators may sound like a good option to have instead of a glasspack, it has been said by professionals that they are not nearly as effective in reducing sound in comparison to a long glasspack. A short glasspack has a similar effect as a resonator, so that is something to keep in mind when determining whether or not you should buy a resonator or a glasspack.

[Related Article: How To Reduce Noise For Your Motorcycle Helmet In 8 Simple Steps]

How Does a Glasspack Work?

A glasspack is a type of muffler found in cars, trucks, and other vehicles. It is used to reduce back pressure in automobiles. Back pressure is defined as “a resistance or force opposing the desired flow of fluid through pipes, leading to friction loss and pressure drop”. This is how a glasspack works:

  • Exhaust gas passes through the middle: The exhaust gas coming from the vehicle passes through the middle of the muffler, which creates a barrier between the inner glasspack and the rest of the pipe.
  • Sound energy to physical energy: It takes sound energy and converts it in physical energy by moving the fiberglass fibers. These fiberglass fibers absorb the sound waves which helps muffle the sound coming from the front end of the automobile and it relays it to the back.
  • Creating turbulence: When you hear the roar of the engine, that is the motor creating turbulence. The turbulence helps propel the vehicle and helps movement on the back end.

Why is My Glasspack Not Quiet?

Glasspacks are one of the oldest and most simple designs of mufflers. While they help with reducing pressure in the back end of the vehicle, they are well known for being noisy. There are a variety of reasons why your glasspack is not quiet:

  • Age
  • Length
  • Shape
  • Constriction
  • Directionality
  • Resonator


While it isn’t the biggest creator of noise in glasspacks, the age of the glasspack will affect the noise. The older the glasspack is, the more likely it is to be loud. This is because age wears out the fiberglass surrounding the pipe and the fiberglass absorbs some of the noise. The best solution to fix this, replace your glasspack with a new model. However, you have to make sure that the new glasspack you get is suitable for your vehicle because newer glasspacks might not work for older vehicles.


There are many varieties of length when it comes to glasspacks. These sizes vary from less than ten inches all the way up to 34 inches. Because of the size difference, there is also a difference in noise. The smaller the glasspack, the louder it will be. Newer models of automobiles tend to have shorter glasspacks and older automobiles tend to have longer glasspacks.

The reason why longer glasspacks are usually quieter is because the sound waves have further to travel, therefore there is less noise coming out of the end of the pipe.


There are two common types of glasspacks- Louver and perforated.

There might not be a huge difference in sound between the two forms but, because of the diameter of Louver glasspacks, Louver glasspacks are more likely to be louder. Therefore, perforated glasspacks are more likely to be quieter.

  • Louver: Louver glasspacks are more common in older vehicles. The difference between the two forms of glasspacks is that Louver is an obstructed pipe and a perforated is an unobstructed pipe. There might not be a huge difference in sound between the two forms but, because of the diameter of Louver glasspacks, Louver glasspacks are more likely to be louder. Therefore, perforated glasspacks are more likely to be quieter.
  • Perforated: Perforated glasspacks are more common for vehicles made since the 2000s.

Older automobiles were likely to have their pipes “necked down” which means that the sound waves are trapped in the front of the pipe which causes the sound to be canceled, which makes it quieter.


The direction of the glasspack, whether it be forward or backwards, can change a bit of the volume on your glasspack. The proper way for the direction of the glasspack is forward, so make sure it is on the right way in order for the noise to be correct.


While it is not the main factor in noise control, the pitch of your muffler can be helped by using a resonator. It can take the high pitched, screeching noise coming from the back of your car and turn in into a low, mellow noise.

[Related Article: How To Soundproof Noise From Boat Engine – Inboard & Outboard Motor]

The Best Glasspack Products

The internet is a great resource to find glasspack products that will suit the needs of your vehicle. Amazon, while not being very well known for its selection of car parts, actually has many incredible options when it comes to useful glasspacks.

Cherry Bomb 87522 Glasspack Muffler

This Cherry Bomb 87522 glasspack muffler has over 240 reviews with the average rating being 4.5 stars. It is 8 inches, so it is a bit on the shorter side, but it has many impressive design features such as the straight through design and its reversible, compact design. Many reviewers also say that the quality of its deep, mellow sound is great.

AP Exhaust 351211S Glasspack Muffler

This AP Exhaust 351211S glasspack muffler is a great value for just slightly over $25. It has an average of 4.5 stars when it comes to ratings. Reviewers noticed the high quality and great sound of this aluminized glass pack.

This powerful 2.25 inch Red Hot Flowtech glasspack muffler is known for being durable and long lasting. It has an average review of 4.4 stars out of 5 stars and reviewers say that it is easy to install and performs really well.

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