Even though you might drive your car every day, have you stopped to think about how the exhaust system works? I got into a heated discussion recently with a coworker about where the resonator goes in relation to the muffler, and I thought I should share the results with you.
To put it simply, a resonator should always go before your muffler in the exhaust system. Putting a resonator after the muffler will make the resonator useless. The resonator’s job is to change the frequency and resonance of the noise in your exhaust system. Doing this makes it easier for your muffler to restrict the volume and make everything quieter.
In this guide, I’ll answer the simple question, should you install a resonator before or after the muffler? I’ll also give you some insight into how these parts work, why they matter, and whether or not you even need them.
Explaining Your Exhaust System
Before getting into the sequence of your resonator and muffler, I need to explain what’s going on in your car’s exhaust system. It might just seem like a stretch of metal tubing, but there’s a lot of science going on.
First and foremost, let’s look at the engine. Inside your engine block, a ton of little explosions are happening. Fuel is mixing with air, compressing, getting ignited, exploding, and creating energy. This energy is used to drive your car forward.
The downside is that these explosions are very loud and create toxic gas — gas that can kill you if you breathe it in.
Instead of letting the noise and gas fill the engine compartment, engineers came up with a way to get rid of it: your exhaust system.
That’s right, your exhaust system has two jobs. It takes away the toxic gas, cleans it, then releases it. It also takes away the deafening noise of your engine and makes it quieter.
Through a combination of a manifold or header, metal tubes, catalytic converter, resonator, muffler, and tailpipe, your exhaust system does both of its jobs very well.
You can pop your hood, put your head in the engine compartment, and you won’t pass out or go deaf thanks to the exhaust system.
Through those parts that I just mentioned, the fumes are carried along with most of the noise. The catalytic converter cleans up the fumes, and the muffler and resonator are there to make things quieter.
What Is a Muffler?
The simple goal of your vehicle’s muffler is to change how loud your exhaust is. As the name suggests, it muffles the noise.
Mufflers typically have a few chambers and baffles inside, but they just look like a block of metal from the outside. Each of these chambers and baffles is designed to dissipate noise and make your exhaust much quieter.
This is a good thing since excessively noisy cars are illegal in all 50 states.
Every legal stock road vehicle in America comes with a muffler to eliminate a certain amount of engine noise.
In fact, people use their mufflers to troubleshoot exhaust troubles. If their exhaust is making a much louder noise, there’s a good chance there’s a crack, rust, or hole in the muffler or any of the tubings before the muffler.
What Is a Resonator?
The resonator on your vehicle changes the resonance of your vehicle’s exhaust note. What does that mean? Well, resonance is how a sound actually sounds. It refers to the frequency of the sound waves.
If something sounds high-pitched, that’s because the sound waves have a higher frequency. Another thing to mention is that certain frequencies are a lot harder to cancel out.
The goal of your resonator is to make your exhaust noise a certain frequency that’s easier to muffle.
If you take two of the same car and remove the resonator on one of them, you’ll probably hear a difference as they’re running. The one without the resonator will have a humming undertone, higher-pitched noises coming from the tailpipe, and the final sound will be a bit louder.
The Reason Your Engine Isn’t Silent
You might be scratching your head now. I mentioned that a resonator is only there to change the frequency of the exhaust, but why does that matter? Why do you even need a muffler in the first place — can’t your engine just be quieter?
There’s a trade-off between engine noise and performance. At a NASCAR race, you have to wear hearing protection because the cars are so powerful and loud. As engines get more powerful, they typically get bigger and louder.
If you want a silent vehicle that doesn’t have a muffler or resonator, then you would need a severely underpowered engine.
Instead, auto manufacturers create engines that are powerful enough for the market and include resonators and mufflers to dissipate most of the noise.
Mufflers Aren’t 100% Effective
Another point of confusion that people have is why cars make any noise at all if they have a muffler. After all, isn’t the muffler supposed to be like a silencer on your car?
This is a good observation, and it really highlights how loud engines are in the first place. Engine noise is so loud that even with specifically engineered resonators and mufflers, you’ll still be able to hear them.
The exception to this rule is any car that doesn’t have an engine, like an electric vehicle (EV).
Mufflers are optimized and dampen as much noise as they can, but they won’t remove 100% of your engine’s noise.
To do that would require a bigger, more expensive, more complicated muffler. It’s just not worth it for everyday consumer vehicles.
Should You Install a Resonator Before or After Muffler?
You might have guessed the answer by now, but in this section, I’ll explain if you should install a resonator before or after the muffler.
As a refresher: the resonator changes the pitch of your engine noise, and the muffler makes it quieter.
With that reasoning in mind, it makes sense that the resonator comes before the muffler on every vehicle. The resonator takes very high and low frequencies and funnels them into a more normalized resonance. From there, it feeds the noise into the muffler for it to do its job.
Since the frequencies are closer to the optimal resonance, the muffler can dampen more noise.
If you were to swap the position, and have the muffler before the resonator, then your tailpipe will be a lot louder. Higher and lower frequencies will get through the muffler without getting dampened, and the resonator would do nothing to quiet them after the fact.
It’s like putting the flour and eggs into your cake after taking it out of the oven. If the process isn’t right, then the final product won’t be right.
Not All Cars Have Resonators
It might be surprising to learn this, but not all cars have resonators. Since these are more expensive, you’ll typically find them in more luxurious cars like a Lexus. It’s how they achieve a quieter ride and fewer annoying buzzes and hums while driving.
However, plenty of entry-level sedans also have resonators. The best way to know is to look at the undercarriage of your vehicle and spot the exhaust system. You should notice the resonator between the catalytic converter and the muffler.
If it’s just a regular pipe going from the catalytic converter to the muffler, then there’s no resonator.
Frequently Asked Questions (FAQ)
Q: Do You Need a Resonator?
A: There is a process called a “resonator delete”, which entails removing the resonator from your car. Does that mean that your resonator is a useless piece of metal? No.
In reality, you don’t need a resonator on your vehicle for it to be street-legal. As long as you keep your muffler installed and intact, there’s nothing prohibiting you from doing a resonator delete.
However, the average driver really won’t notice a difference before and after removing their resonator. The difference in backpressure and weight won’t amount to much — you won’t notice a change in fuel efficiency, performance, or drivability.
If you have a trained ear, you might notice a different exhaust note and volume, but that’s about it.
In my opinion, it’s not worth it to remove your resonator. But, there’s nothing preventing you from doing it.
Q: Do You Need a Muffler?
A: For mufflers, it’s a different story. Since the muffler is there to eliminate a lot of exhaust noise, it’s a requirement for any street-legal vehicle. There are also “muffler deletes” that you can do to your vehicle, where you take the muffler out and replace it with a straight tube.
Doing this will make your car illegal to drive in all 50 states. It’s also something that vehicle inspectors are trained to look and listen for. If they come across a car with no muffler, then they’ll fail your vehicle and deem it illegal to drive on public roads.
Deleting a muffler has a much bigger impact than removing the resonator. In this case, you’ll notice a huge noise difference, and you might notice a performance increase if you’re in tune with your car.
But just to reiterate, you can’t drive your car on public roads after removing the muffler. You need a muffler if you want to have a street-legal car.
I just covered a lot about mufflers and resonators, as well as how your car’s exhaust system works. By now, you should know that the resonator always comes before the muffler if you want to see the best results.