Exhaust System Resonator

[Shel_B]

How does a resonator alter the sound of an exhaust system? Does it create back pressure, as some mufflers do? I've heard of people removing the resonator in their system so I would imagine it's not a very important piece of the exhaust system, unlike a cat or a muffler.

 

[atikovi]

It's usually a packaging decision by the car manufacturer. When one muffler would be too big to fit under the car for ideal sound reduction, a smaller one is fitted along with a resonator for an extra 10-20% noise reduction. Most are straight through, so no significant added back pressure.

 

[Skippy722]

Here’s a video showing a sound difference all else being equal. On HEMI’s removing the resonators tends to create a bit more drone than removing/replacing the muffler.

I removed the resonators on my Durango and while it sounded good it definitely droned a bit On the highway. I replaced the factory muffler with a flowmaster on my ram but kept the resonator, definitely louder though.

 

[kschachn]

How does a resonator alter the sound of an exhaust system? Does it create back pressure, as some mufflers do? I've heard of people removing the resonator in their system so I would imagine it's not a very important piece of the exhaust system, unlike a cat or a muffler.

As noted it may not be a "very important" piece but it does reduce the emission of certain frequencies. A resonator (any resonator) is a cavity that resonates at a particular frequency and has some sort of mass to dampen the energy. All sorts of equipment use them (look up rockets) to reduce sound pressure or mechanical vibration of a specified frequency. More sophisticated ones have active damping to attenuate a range of frequencies.

 

[ARCOgraphite]

Das ist wichtig !

 

[Shel_B]

Das ist wichtig !

View attachment 139404

What is this supposed to mean or represent?

 

[ARCOgraphite]

Professor of physiology at Koenigsberg, Dr. Hermann von Hemholtz

 

[Shel_B]

Professor of physiology at Koenigsberg, Dr. Hermann von Hemholtz

Now that you've said who this person is, perhaps you can take a moment to respond to the question. What does he have to do with automotive exhaust systems? Please remember, not everyone is as smart as you ...

 

[ARCOgraphite]

The resonator is important as others have said, it is usually specified (tuned) to eliminate specific resonances in the system which may cause a loud "droning" at a certain engine rpm and specific highway speeds.
It's like tuning and Organ pipe or the box resonance in a ported loudspeaker but to reverse effect: mitigation.
Dr. Hemholtz, a brilliant polymath from the mid 19th century, was a pioneer in this area of acoustics and auditory perception which eventually crossed over into electronic circuits decades later.

My question to you is, do you have a rusted or damaged resonator on the Camry? Just wondering why the general query.

By the by, I ain't so smart ! My Highschool Science teacher - Mr. Wilkinson - made us learn just a bit about each person behind the science. Somehow I remember this - and I don't have a good memory!

Amps - Andre-Marie Ampere
Watts - James Watt
Ohms - Georg Ohm - looks like Beethoven !
Volts - Alessandro Volta
Torr - Evangelista Torricelli
Joule - James Joule - Our teacher pronounced his name Jowl

and ... a couple more that I do now forget !

- Ken

 

[Shel_B]

The resonator is important as others have said, it is usually specified (tuned) to eliminate specific resonances in the system which may cause a loud "droning" at a certain engine rpm and specific highway speeds.
It's like tuning and Organ pipe or the box resonance in a ported loudspeaker but to reverse effect: mitigation.
Dr. Hemholtz, a brilliant polymath from the mid 19th century, was a pioneer in this area of acoustics and auditory perception which eventually crossed over into electronic circuits decades later.

My question to you is, do you have a rusted or damaged resonator on the Camry? Just wondering why the general query.

Thanks for the explanation.

The exhaust system on the Camry is just fine, although last year I replaced the rusted flex pipe.

A few days ago I was watching one of the car repair YouTubers and he was under the car pointing out various items and features. He pointed out the resonator and the muffler, and that started my hamster-wheel brain spinning and thinking about the resonator. I realized I was ignorant of its whys and wherefores, and here we are.

 

[Cujet]

Here is an example of a Helmholtz resonator tuned to reduce a particularly annoying frequency

 

[Brian123]

The resonator is important as others have said, it is usually specified (tuned) to eliminate specific resonances in the system which may cause a loud "droning" at a certain engine rpm and specific highway speeds.
It's like tuning and Organ pipe or the box resonance in a ported loudspeaker but to reverse effect: mitigation.
Dr. Hemholtz, a brilliant polymath from the mid 19th century, was a pioneer in this area of acoustics and auditory perception which eventually crossed over into electronic circuits decades later.

My question to you is, do you have a rusted or damaged resonator on the Camry? Just wondering why the general query.

By the by, I ain't so smart ! My Highschool Science teacher - Mr. Wilkinson - made us learn just a bit about each person behind the science. Somehow I remember this - and I don't have a good memory!

Amps - Andre-Marie Ampere
Watts - James Watt
Ohms - Georg Ohm - looks like Beethoven !
Volts - Alessandro Volta
Torr - Evangelista Torricelli
Joule - James Joule - Our teacher pronounced his name Jowl

and ... a couple more that I do now forget !

- Ken

I have seen this also where the resonator was deleted by certain people, and later they complained about certain noises. I also saw where certain people changed there mufflers and it was great for awhile, but later it was an annoyance. Hot Rod Magazine back in the 1980's or maybe later, think the artcile was called Merrie Melodies showed in a dyno test that there was not much of a difference in the Horespower of a car.

Back to the OP's question, a resonator may help with a better sound, as far as Backpressure, unless you have alot of Horespower this is a non issue. Todays cars are not going to be put out there with an exhaust causing issues.

 

[Egg_Head]

I had a 1993 Volvo 944 Turbo. The low-buck upgrade then was to delete the resonator and muffler and just add back a Flowmaster 50 series muffler and stock pig-tail pipe welded back on the end. Best sounding tone, zero drone, I have ever heard in a "sleeper" package. Most turbos abate the exhaust noise enough that the resonator-delete is not obnoxious, NA cars are a different story.

 

[wtd]

I installed some over the axle pipes in my 2014 Mustang GT that eliminated the resonators and I did not get any drone. I'm also running GT 500 mufflers which I put on prior to the OTA pipes. It gave my car a deeper tone without the resonators. I think it depends on what mufflers you are running in conjunction with no resonators on whether you will get any additional drone.

 

[kschachn]

Also as an aside many cars have a resonator or two on the intake as well.

 

[Jmitchelltfo]

I installed a Unitronic catback (factory tune and DP) on my Mk8 GTi and there is a noticeable, but not terribly bad drone around 2500 rpm. That happens to be exactly where I spend most of the time when I’m on the interstate with my 6 speed. I love the tone and volume otherwise though.

I watched quite a few videos about Helmholtz/quarter wave/J pipe resonators and this one was the most informative about the science and practical application of curing drone. After doing the calculations based on the spreadsheet that was linked in the video, I came up with 51 inches as the optimal length. I’ll either have to do multiple 180° bends (like shown in the video) or try to squeeze a 51” J pipe in the mid pipe area.

I’m 42 and already have tinnitus from too many unplanned weapons free situations, where I was caught without ear pro. I’m sure most younger guys wouldn’t be bothered by this issue, but I’d really like to take care of it.

 

[K20FA5]

I’ve heard of a lot of guys complaining about the chopper sound on the GM trucks with the AFM. I wanted mine a bit louder but didn’t want that sound or the drone. I ended up removing my stock muffler and the flapper valve, since it was starting to squeak, and replaced it with a Borla Touring muffler. I kept the stock resonator by the tailpipe. It’s a little louder, and I don’t hear the chopper sound when AFM kicks in. It was obviously tuned for the V4 sound.

 

[AZjeff]

Das ist wichtig !

Is German for that is important. Imagine he was responding to the well written explanation preceding his response.

He might have meant Das is richtig which is that is correct.