Resonator Delete vs. Muffler Delete

What is the difference between a resonator delete and a muffler delete? What are the pros and cons, and is it even legal? Here's the ultimate guide.

Resonator delete vs. muffler delete. Which is better? Can you do both? Are they legal?

Let’s start with the most important and all-encompassing factor. It’s against the law to remove the muffler.

You can’t break the law for the sake of making your car sound a bit better.

Instead, consider performance cat-back exhausts or exhaust tips. You should still check that they’re permitted in your local area – they might not be.

If you’re looking to remove your exhaust or muffler for a racecar or non-road vehicle, read on. If you’re looking for tips to improve your car’s noise, skip to the end.

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What Is An Exhaust Muffler?

Exhaust Muffler

An exhaust muffler is a cuboid or cylinder towards the end of the system. On most cars, you can see it from the back. The pipe flows into it, and the exhaust tip – the very end – comes out.

Mufflers are designed to reduce your exhaust noise as much as possible.

If you were to cut one open, you’d find a series of pipes and chambers. The sound vibrations bounce through this space, losing energy as they’re absorbed by the walls.

The noise is drastically reduced when it gets out of your exhaust tip.

A muffler isn’t the only part of your exhaust system that reduces noise, although it is dedicated to this. The catalytic converter also slows the gas flow rate. This has the side effect of reducing noise (and engine power).

Removing your catalytic converter is also illegal, though.

What Is An Exhaust Resonator?

Exhaust Resonator

Resonators are also found in almost every passenger car. They’re a clever and surprisingly carefully engineered piece of kit.

You’ll find them together with your muffler (usually just before it).

Resonators are another chamber in your exhaust system. As the sound waves pass through, they echo within it.

Acoustic engineers create resonators to precise specifications. As the waves bounce and stretch (echo), they begin to collide with each other.

This phenomenon is known as destructive interference. It happens when two waves of equal frequency but opposite magnitude collide. They then cancel each other out, and from the noise, you get silence. Crazy but true.

Resonators aren’t about reducing noise levels, like the resonator. Their job is to eliminate all the high-pitched whining sounds – the ones nobody wants to hear!

Muffler Delete: Pros And Cons

Muffler Delete

Before discussing the pros and cons of muffler removal, remember it’s illegal. Everything discussed here applies only to non-road vehicles like racecars. Even then, you’ll need to check local and motorsport regulations.

A muffler delete’s primary and perhaps only advantage is a louder, throatier noise. Without all that sound-suppressing, you’ll end up with a much more aggressive car.

Despite what you might hear, a muffler delete won’t add much horsepower – if any. You might see microscopic gains, sure, but nothing noticeable whatsoever. That’s because the exhaust gas flow rate doesn’t improve significantly.

In racing situations, you might be looking to lose weight. If you’re permitted, removing the muffler might save you 10 lbs or so. If your car has two exhausts, double that.

Resonator Delete: Pros And Cons

Resonator Delete

Removing the resonator isn’t necessarily illegal. You’ll need to check local regulations, but many aftermarket modifications offer resonator bypasses.

But why would you? There are little to no benefits to removing your resonator. You’ll save a couple of pounds in weight, but that’s about it.

Some might claim that your exhaust will get better flow and improve your horsepower. Any gains will be minimal and, so far as you’re concerned, completely negligible.

Without the resonator, you’ll start hearing high-pitched grating frequencies. Your car will sound worse; there will be no real benefit whatsoever.

What’s the point? You should always leave the resonator alone!

How Much Is A Muffler And Resonator Delete?

Cost and Price

A muffler and resonator deletion will cost you around $200. Most of this is labor charges.

A technician will simply cut off the old muffler (and resonator, if applicable). They’ll then attach a new pipe of the same diameter.

That’s all there is to it. Yet again, a muffler and/or resonator deletion will make your car illegal for road use. The extra-loud noises you’ll be making mean the police will notice, too.

Save yourself money, time, and cop fines by doing something… well, legal, instead. See the next section for some suggestions.

Instead Of Muffler Or Resonator Deletes, Try These Alternatives…

Cat Back Exhaust System

If this guide has taught you nothing, it can be summed up here (and in the next section). Don’t waste your time with either muffler or resonator deletes!

Aftermarket exhausts with straight pipes avoid the catalytic converter, resonator, and muffler. You know what? Highly against the law. You should also avoid using one (unless it’s for racing purposes).

So, what can you do for a more assertive exhaust noise? Well, look at legitimate aftermarket exhaust systems. Road legal applications will be cat-backs – they attach to the catalytic converter and replace your exhaust from here through to the tip.

Yet again, you should check local noise regulations before installing one. Provided the performance exhaust comes with a muffler and resonator (which it should), you’ll probably be okay.


Don’t neglect to check!

Here’s some more information on the noise limits and laws in each state.

Which Is Better: Muffler Delete Or Resonator Delete?


It should be obvious that removing a muffler or a resonator is not recommended.

The only exception might be in racing scenarios if local authorities and motorsport regulators allow it.

It’s never a good idea to remove the resonator. A muffler delete might shed a little weight and improve your car’s noise. But it’s still illegal, so…

Instead of a muffler or resonator delete, look for cat-back performance exhausts or exhaust tips. These are more likely to be legal, but you should still check your local laws.

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Benjamin Kitchen

Ben is an IMI-qualified light vehicle technician from England with experience in a fast-fit garage. He aims to help drivers worldwide with common automotive problems. You’ll often find him working with his 1.2 Vauxhall Corsa. It may have a tiny engine, but in eight years it's never once let him down!