What's inside a resonator?

[Bambusiero]

Has anyone opened up an exhaust resonator to
see what's inside?

I'm curious to know if it's an acoustically tuned
"Helmholtz" resonator, where it's the chamber
dimensions that do the magic, or if it's just an
absorber type of thing.

 

[CJF]

I'm curious to know if it's an acoustically tuned
"Helmholtz" resonator, where it's the chamber
dimensions that do the magic, or if it's just an
absorber type of thing.

I have no idea what you're talking about.

HTH ,

Curtis

 

[Bear80]

look right up the tail pipe and you'll find out........which means it's absorber, usally can tell by the holes. Works like a glass pack.

 

[topend yobbo]

make sure you stick your eye right on it while its running to.
Come on fellas PLEASE.

 

[OZCAL]

I've never even looked outside an exhaust resonator to see what's outside of one

 

[Mickldo]

Three inch mandrel bent turbo exhausts don't have resonators.

 

[bjowett]

They are hollow chambers, oems tune them for specific applications. There are aftermarket units that probably work well for some applications, not so well for others.

res·o·na·tor ( P ) Pronunciation Key (rz-ntr)
n.
1. A resonating system.
2. A hollow chamber or cavity with dimensions chosen to permit internal resonant oscillation of electromagnetic or acoustical waves of specific frequencies.
3. A resonant circuit.

 

[Trinny]

They are hollow chambers, oems tune them for specific applications. There are aftermarket units that probably work well for some applications, not so well for others.

res·o·na·tor ( P ) Pronunciation Key (rz-ntr)
n.
1. A resonating system.
2. A hollow chamber or cavity with dimensions chosen to permit internal resonant oscillation of electromagnetic or acoustical waves of specific frequencies.
3. A resonant circuit.

Oh, now I get it





Reduces noise.

 

[NorCalDoug]

dunno what the OEM one has -- I didn't bother picking it up to look inside.

the aftermarket resonator I have was a solid surface (i.e. no holes) with smallish bumps in some sort of pattern on the inside. I took a look at it before the install.

 

[bjowett]

"Oh, now I get it"

All you'll get is the mud salute

 

[Bear80]

What does that mean?

This........ Just recently I had to tie up my tail pipe with zip ties. Happened to look up into the resonator. From what I recall of taking the resonator apart off my celica it did have some material in it. It had the same pattern of holes inside and would just guess that probably the 80 was the same.

 

[FirstToy]

If anyone has a stock resonator they are not using, PM me. I know someone that needs it. Thanks

 

[Beowulf]

I'm curious to know if it's an acoustically tuned
"Helmholtz" resonator ...

I cannot remember where, but I read that it is in fact a Helmholtz resonator.

-B-

 

[Bambusiero]

For some reason that picture makes me nervous.
I'm not even really sure why...

 

[Beowulf]

You mean my avatar?

-B-

 

[Bambusiero]

Beowulf Quote:
I cannot remember where, but I read that it is in fact a Helmholtz resonator.

Ah, sooo, velly impotant!

bjowett (paraphrased) Quote:
They are hollow chambers, oems tune them for specific applications. There are aftermarket units that probably work well for some applications, not so well for others.

res·o·na·tor ( P ) Pronunciation Key (rz-ntr)
n.
2. A hollow chamber or cavity with dimensions chosen to permit internal resonant oscillation of acoustical waves of specific frequencies.

Exactly, thank you, bjowett, for defining it for those that haven't heard of such nerdly stuff. Think of blowing on a Coke bottle (oops, sorry guys) beer bottle, and making it whistle. It's a resonant cavity at a certain frequency (tone). Sound waves travel down the tube, reflect off the far end, and travel back to the opening. Set up the length a certain way and you can either reinforce the source at the opening, or partly cancel it. Speaker makers use the concept all the time for reinforcement. (Bose Wave radio)

Apparently, mufflers do a pretty good job across the frequency range, but some particular tone gets through. So, they put in a special little tuned thingy to cancel out that particular tone. The resonator.
Hey, look at the size of those things. No way a little "glass pack" that size could do much. The BIG ones don't do much!

SOME people cut the thing off and get annoying droning or whistling in a certain RPM band.
Or, some OTHER people put in

Three inch mandrel bent turbo exhausts don't have resonators.

and they get whatever they get, who knows?

NorCalDoug Quote:
dunno what the OEM one has -- I didn't bother picking it up to look inside.

the aftermarket resonator I have was a solid surface (i.e. no holes) with smallish bumps in some sort of pattern on the inside. I took a look at it before the install.

So here's the thing. I think it would be just lucky to pick an aftermarket resonator and have it work. It has to be tuned to your engine & exhaust system design.
Change mufflers or cats very much, and you might change the sonic character of the whole system.

How many muffler shop guys do you think are up on this stuff?

BTW, there's another resonant damper (mechanical) built into the resonator mount. It looks like a rubber knob with no apperant purpose. I think the factory engineers put it there for some good reason.

 

[MaddBaggins]

Probably some family of bugs or something livin in mine since I cut it off and tossed it in the bushes.
2-1/2 pipe, 40 series Flowmaster and very hi flowing cats. Everything tucked up and outta the way, sounds like the James Earl Jones of ricers.

 

[Bambusiero]

Hey Baggins,

Got any photos of your rig's "Everything tucked up and outta the way" exhaust routing, under-the-frame pipe, etc.? I'm pondering such things right now.

 

[MaddBaggins]

Hey Baggins,

Got any photos of your rig's "Everything tucked up and outta the way" exhaust routing, under-the-frame pipe, etc.? I'm pondering such things right now.

I'll snap a few pics this afternoon. I will probably go to PHX next month for the CSC meeting if you want to get an up close look (I'm in Tucson)

 

[re_guderian]

SOME people cut the thing off and get annoying droning or whistling in a certain RPM band.

Yep. Got the whistle going on wih the exhaust coming through the rear bumper.