The catalytic converter and muffler are important components of an exhaust system. Although their jobs are different, exhaust gases pass through both parts.
Understanding how these parts work is also important for deciding which modifications will be the most effective when it comes to adding horsepower to your vehicle.
The big difference between a catalytic converter and muffler lies in the specific function each performs.
In what follows we’ll walk you through these differences as well as show you how these parts work together in our exploration of the exhaust system.
What’s a Catalytic Converter?
In short, a catalytic converter’s duty is to convert harmful gases from the combustion in an engine into less harmful emissions.
Every commercial and passenger vehicle manufactured after 1975 that’s legally allowed to use our public streets and highways with an internal combustion engine has a catalytic converter.
The pollutants caused by the exhaust of an engine include carbon monoxide, hydrocarbons and nitrogen oxide.
Exhaust emissions contribute to poor air quality, environmental pollution and respiratory illnesses like asthma.
As a public good, the EPA (Environmental Protection Agency) strengthened emissions control regulations, which lead to the mandate that every road vehicle should be manufactured with a catalytic converter.
What’s a Muffler?
Further down the exhaust system toward the rear bumper of a road vehicle is the muffler.
A muffler is designed to reduce the amount of emissions produced by an engine. And dampen the noise level of exhaust gases as they exit the tail pipe.
Mufflers are mostly used to turn down the volume of an engine while it’s in operation.
The Distance Between a Catalytic Converter and Muffler
In every vehicle the catalytic converter comes before the muffler.
You’ll always find the catalytic converter beneath a vehicle closer to the front with the muffler downstream closer to the rear.
To quieten the sound of exhaust gases exiting the tail pipe some vehicles are equipped with a resonator which you’ll find between the catalytic converter and muffler.
All these components work together with the rest of the exhaust system to expel gases from the engine.
Additionally, do you know why the muffler and exhaust pipe are almost always positioned at the rear of a vehicle?
It’s because the further away the muffler is from the front of the engine the quieter the vehicle will be. Some performance cars – like muscle cars – have what’s called a side dump exhaust.
Not only do I think this makes the car look more aggressive. But their close proximity with the engine also makes the car sound more aggressive.
It’s something I wanted to do to my Mustang before I wrecked it.
How Are Exhaust Gases Created in the First Place?
Inside an engine are cylinders. Above those cylinders are valves that open and close: intake and exhaust valves.
In a fuel injected engine fuel injectors spray gasoline into the cylinders. The intake valves open to allow oxygen into the cylinders.
This combination of gasoline and air causes a miniature explosion called a combustion which creates harmful gases and fumes.
Then the exhaust valves open to let those harmful gases and fumes escape the cylinder so that the cycle can happen again.
How Exhaust Gases Travel Through the Exhaust System
The gases and fumes then travel to an exhaust manifold from a port for each cylinder.
From the exhaust manifold those harmful gases and fumes travel to the catalytic converter where the harmful pollutants get cleaned out.
Then the exhaust gases travel through the catback which is a long pipe connecting the catalytic converter to the muffler.
Once in the muffler the exhaust gases are cleaned again and the sound they make as they travel through the exhaust system are quietened before they escape out the tail pipe as emissions.
Catalytic Converter vs Muffler Delete
A muffler delete eliminates the muffler and tail pipe but leaves the catalytic converter intact. The reason for this modification is to make your vehicle sound louder.
Which it will.
But before you do that I recommend checking with your local city and state ordinances to find out how legal making this kind of modification is if you plan to use your car, truck or SUV on public roads.
Otherwise, you could face emissions and noise violations which come with fines.
How a Muffler Suppresses Engine Noise
The consequence of an engine creating the power it needs to move a vehicle forward or backward is the creation of a lot of pulsating noises.
To cancel out these noises the inside of a muffler consists of chambers, baffles and tubes. These components work together to cancel out the sounds coming from an engine.
Catalytic Converter Theft
Thankfully this has never happened to one of my vehicles.
But catalytic converter theft is a thing, and you should be aware of it.
This exhaust component is the target of thieves because it’s made of precious metals like platinum, palladium and rhodium which are what act as a catalyst to transform pollutants from exhaust gases like carbon monoxide, hydrocarbons and nitrogen oxide into less harmful emissions.
And now that we’re facing supply chain issues the simple law of supply and demand have made catalytic converters even more coveted by thieves.
Vehicles with the Most Number of Stolen Catalytic Converters
Carfax looked at the service reports of more than 60,000 mechanics across the U.S. of vehicles that came in for a catalytic converter replacement.
They found that the list of targeted vehicles include:
1985-2021 Ford F-Series
1989-2020 Honda Accord
2007-2017 Jeep Patriot
1990-2022 Ford Econoline
1999-2021 Chevrolet Silverado
You’ll know if the catalytic converter has been stolen from your vehicle because the engine will sound A LOT LOUDER. And unless you have full coverage insurance, you’ll be on your own to replace it to the tune of $1,000 to $3,000.
Law makers are working to solve this problem.