Exhaust Systems

Exhaust Systems

The exhaust system is designed to reduce noise and air pollution. Your car’s engine creates both and the exhaust system helps to lessen their effect. According to the Union of Concerned Scientists, “Transportation is the largest single source of air pollution in the United States.” Making sure the exhaust system is doing its job is important.

If you notice bad smells coming from your exhaust pipe or if your car is backfiring, you may have a problem with the exhaust system. Below is an overview of the exhaust system components and the roles they play.

Exhaust Manifold

As toxic fumes leave the engine, they exit through the exhaust manifold(s) and travel to the catalytic converter(s).

Catalytic Converter

The catalytic converter is encased in a stainless steel housing that contains ceramic blocks. These blocks hold thousands of micro ducts (nearly 400 per square inch), which are coated with precious metals. As fumes travel through these ducts, a chemical reaction transforms the toxic gases into oxygen, nitrogen, carbon dioxide and water vapor. (The primary composition of air is a mixture 78% nitrogen, 21% oxygen, along with water vapor, carbon dioxide, argon, and various other components.)

But here’s the catch, the catalytic converter works most efficiently when it is heated up (we’re talking 1300 degrees). A car has to drive about six miles before it heats up the catalytic converter, which means that short car trips are causing a lot more pollution. So combining errands isn’t just good for your schedule, it’s better for the planet.

Ideally, a catalytic converter should last about 100,000 miles. Sometimes a car can bottom out or run over a big rock and cause damage to it. An engine burning excessive oil can also cause a catalytic converter to wear out prematurely. So maintaining your car properly can save you a lot of money in the long run. Even certain fuel additives can contribute to a shorter life span of your catalytic converter.


After going through the catalytic converter, the transformed gases, along with sound waves from the engine, travel along the resonator. This is a steel tube that helps to reduce sound waves.


Next, exhaust gases and sound waves travel through exhaust pipes to the muffler. The muffler is made up of expansion chambers of different sizes. The first chamber is covered in drill holes. As sound waves emerge from the tiny holes, their movement is restricted. This causes friction and destroys many of the sound waves. Sound waves with greater intensity travel into the second chamber where they collide with the walls and are destroyed due to further friction. Sound waves with the greatest intensity travel on to the Helmholtz resonator where they collide with the wall of the resonator, bouncing back and creating an opposite sound wave of the same frequency that cancels it out. In the third chamber, noise is further reduced as a result of friction. The end result? Muffled sound.

Tail Pipe

When the exhaust system has eliminated all of the gases it can, the remaining gases and vapors are released into the atmosphere via the tail pipe. gases. The tail pipe can get very hot, so be careful not to touch it when the car has been running. You may occasionally see water dripping from the tail pipe. It is a result of water vapor formed in the catalytic converter.

Hangers & Brackets

Most of the exhaust system is suspended from the underside of the car by a series of brackets and hangers. If one or more of them gives out, you may hear a scraping noise as a section of your exhaust system runs along the ground. Taking care of this right away will save you money. Like many mechanical issues, the longer it goes unresolved, the more expensive it can get.