What Does the Exhaust Damper Do?

[gaijin]

Anyone know the purpose of the Exhaust Damper which is located on the tailpipe just in front of the Resonator next to the spare tire?

Here's a drawing from the Tech Manual:

The Manual has no explanation of the part

Any help is appreciated.

 

[bjowett]

It eliminates or reduces vibrations so we have a comfy driving experience.

 

[gaijin]

It eliminates or reduces vibrations so we have a comfy driving experience.

Well ... from the name of the part, that was my thought also.

But ... I have never seen such a thing on any other vehicle - ever - in any vehicle I have ever known or worked on in 50 years of playing around with cars/trucks.

It's located only a couple of feet away in either direction from heavy rubber mounting points. It's hard to imagine that any vibration/sympathetic vibration could possibly manifest itself in that part of the exhaust system.

This is not a small part - it's about 2.5" in diameter.

I suspect there is a "story behind the story" about this part and am hoping that someone might have heard it.

Do all LC200's have this part?

Do other LC series have this part? I didn't have it on my LC100, LC80 or LC40.

It's very curious. What kind of horrendous symptom must have occured (and why?) for Toyota to have engineered and implemented use of this part?

I'm hoping someone can shed some light on this so it doesn't become one of life's unsolved mysteries.

 

[jcmiro]

Think of an exhaust like a horn or trumpet. When you open a valve or compartment the sound changes. What this part does is change or muffle part of the frequencies that we perceive as annoying.

 

[gaijin]

Think of an exhaust like a horn or trumpet. When you open a valve or compartment the sound changes. What this part does is change or muffle part of the frequencies that we perceive as annoying.

So ... ALL other exhaust systems that do NOT have such a damper emit "frequencies that we perceive as annoying?"

 

[bjowett]

These weights are added to various components, all with same intent. In the case of our exhaust, there is a vibration frequency present in the system that Toyota has deemed unacceptable. That vibration could create a sound we find annoying, or even a physical vibration that can cause durability issues. Our combination of engine and/or the design of the exhaust are unique to the vehicle... they create it, the weight deals with it. I suspect we see more of these today because NHV standards are much higher, and they are easier to design into things with today's computers.

 

[jcmiro]

@gaijin: nope...It depends, but I suspect not all our exhausts and manifolds have the same design spec.

 

[lx200inAR]

Well ... from the name of the part, that was my thought also.

But ... I have never seen such a thing on any other vehicle - ever - in any vehicle I have ever known or worked on in 50 years of playing around with cars/trucks.

It's located only a couple of feet away in either direction from heavy rubber mounting points. It's hard to imagine that any vibration/sympathetic vibration could possibly manifest itself in that part of the exhaust system.

This is not a small part - it's about 2.5" in diameter.

I suspect there is a "story behind the story" about this part and am hoping that someone might have heard it.

Do all LC200's have this part?

Do other LC series have this part? I didn't have it on my LC100, LC80 or LC40.

It's very curious. What kind of horrendous symptom must have occured (and why?) for Toyota to have engineered and implemented use of this part?

I'm hoping someone can shed some light on this so it doesn't become one of life's unsolved mysteries.

I was googling the same question and this post is the first that came up. With a little more research i found some more info. It does appear that Toyota is starting to install these more as a quick google of "Toyota Exhaust Damper" turns up a gaggle of part numbers. It appears it is purely there to improve exhaust noise.

I found a pdf on ClubLexus that is called "FUNDAMENTALS OF NOISE, VIBRATION, AND HARSHNESS", I guess published by Toyota. There is a section of the guide called "Dynamic Dampers" on page 26. I believe this is what is installed on the exhaust pipe.

Club Lexus PDF Link

Here's the relevant text:

A dynamic damper consists of springs (rubber) and a plumb weight
that are fitted to a resonance system. When a dynamic damper is
added, a large vibration having a single natural frequency is divided
into two vibrations having two smaller natural frequencies.
The vibration level and sound pressure level are reduced as a result.

Edit: adding PDF here.

 

[lx200inAR]

Surely this wins Zombie post of the day.

 

[hoser]

100 series had these mass dampers as well (case by case). 4-5 different sizes depending on the resonant frequency (Toyota called it "booming"). This is in addition to the frame damper/weight.