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The Official Exhaust Resonance Post!

 
Old 08-21-2007, 12:00 PM
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jakers
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Default The Official Exhaust Resonance Post!

I would like to consolidate the info on how the C4 nation has reduced or eliminated resonance. Yeah I know, go spend a $1200 on a Corsa, well for some of us that may not be a viable option in the immediate future! So anything else work. Say like cats or cones in the header etc... etc... ?

If you have successfully limited or eliminated resonance please share your technology...
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Old 08-21-2007, 12:15 PM
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Strick
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It seems that a louder exhaust system will produce resonance. If resonance is a problem you can't live with, stay with the OEM exhaust. It's a good exhaust with good flow, at least for the 92-96. It also seems that you should make sure your tips are at least 1" past the rear of the car. Also, make sure the entire system is not touching any part of the Vette except the hangers. Another thing that seems to produce resonance is the diameter of the exhaust system. The larger the diameter the more resonance is produced. Why? I don't have a clue except for slower flow. Some claim an "X" pipe will reduce resonance, some (like B&B folks) say removing the resonator and replacing it with an X pipe will produce about 30% more resonance and sound. I don't think anyone has the real answer to a loud exhaust with no resonance. Please prove me wrong.
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Old 08-21-2007, 12:21 PM
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Great idea to consolidate. I've been asking a lot of the same questions lately. Resonance is definately an important issue to me yet I like the sound of modified exhausts. What about LT headers with the stock exhaust? Does it produce more resonance?

I'm curious to see what people put for their aftermarket setups and how much resonance it causes.
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Old 08-21-2007, 12:25 PM
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You can extend the tips past the bumper, put in crossovers in the rear Y, or put steel wool in one of the outlets or plug it on longer trips. Systems that retain the cats generally have less as well.

Otherwise unless you get a particular catback that doesnt have it or doesnt have much, you'll be stuck with it.
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Old 08-21-2007, 01:17 PM
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DOH... should have titled this "official ANTI-resonance post"

I just finished adding even more.
True duals with teh flows on the end.
noisy as F and sounds like a cobra at WOT.
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Old 08-21-2007, 04:44 PM
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Originally Posted by GIJoe View Post
DOH... should have titled this "official ANTI-resonance post"

I just finished adding even more.
True duals with teh flows on the end.
noisy as F and sounds like a cobra at WOT.
You are right, I stand corrected, it should be the anti-resonance post. Maybe we can put together a Cabelas group buy on earmuffs?!
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Old 08-21-2007, 04:48 PM
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Originally Posted by Strick View Post
It seems that a louder exhaust system will produce resonance. If resonance is a problem you can't live with, stay with the OEM exhaust. It's a good exhaust with good flow, at least for the 92-96. It also seems that you should make sure your tips are at least 1" past the rear of the car. Also, make sure the entire system is not touching any part of the Vette except the hangers. Another thing that seems to produce resonance is the diameter of the exhaust system. The larger the diameter the more resonance is produced. Why? I don't have a clue except for slower flow. Some claim an "X" pipe will reduce resonance, some (like B&B folks) say removing the resonator and replacing it with an X pipe will produce about 30% more resonance and sound. I don't think anyone has the real answer to a loud exhaust with no resonance. Please prove me wrong.
Strick, you running a 1st Generation B&B? the "R" word, living with it or what?
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Old 08-21-2007, 05:03 PM
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Originally Posted by jakers View Post
Strick, you running a 1st Generation B&B? the "R" word, living with it or what?
I have 3 catback systems that I swap around. I have the newer version of the B&B catback 3" with resonator and it is pretty good as far as resonance goes. It's just too quiet. My other system is a muffler elim with a X-pipe, and it's loud and loaded with resonance at 1900 rpm if on a slight climb. I run Hooker shorties and OEM cats.
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Old 08-21-2007, 05:08 PM
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BerniesVette
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Has anyone tried running the center resonator with muffler eliminators to see how that sounds?
Bernie
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Old 08-21-2007, 05:14 PM
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Originally Posted by BerniesVette View Post
Has anyone tried running the center resonator with muffler eliminators to see how that sounds?
Bernie
I am running the B&B resonator, 3" B&B pipes, no mufflers, high flow cats, long tube headers........

Very loud......but no resonance....at least that I can hear..

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Old 08-21-2007, 06:57 PM
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1-Extend exhaust tips just past the bumper

2-Cats will dumb the sound down a bit as will manifold vs headers

2-Hangers-Use a rubber bushgin if you can so its not 100% solid mount. less transmits through the body

3-Smaller pipes, less resonance-Larger pipes slows down the exhaust gases, they spend more time tumbling around in the pipe. Low frequency vibrations.

4-Rolled tip muffs (referring to the edges of the muffler case) -Typically have some "give" to them to expand with increasing exhaust pressure. Welded muffs typically dont and almost always have no packing in them either that will absorb sound. .

5-Typically the bigger cased muffler the quieter they will be.

6-Buy a Buick

Having 2 dynomax super turbos (typically a quiet muff) and 2 inline dynomax "bullets" my car should be quiet inside..Its not. I bet $$ if I got rid of the 3" pipes it would quiet down. Resonates inside, quiet outside.

Last edited by cuisinartvette; 08-21-2007 at 07:03 PM.
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Old 08-21-2007, 07:37 PM
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Originally Posted by LT4BUD View Post
I am running the B&B resonator, 3" B&B pipes, no mufflers, high flow cats, long tube headers........

Very loud......but no resonance....at least that I can hear..

Do you find yourself saying: "What did you say?" a lot?
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Old 08-21-2007, 07:47 PM
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i run headers to nascar style side out pipes.. WHAT? Tons of noise and fire!!!
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Old 08-21-2007, 09:51 PM
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This is so simple that it is ridiculous, but I guess people want some off the shelf solution. But it works, nuff said

http://forums.corvetteforum.com/show...hlight=altered

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Old 08-21-2007, 10:08 PM
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Originally Posted by IcemanZ06 View Post
Great idea to consolidate. I've been asking a lot of the same questions lately. Resonance is definately an important issue to me yet I like the sound of modified exhausts. What about LT headers with the stock exhaust? Does it produce more resonance?

I'm curious to see what people put for their aftermarket setups and how much resonance it causes.
...i have a stock 88 and i have quite a bit of resonance.i read that in 1988, gm decided that the convertible 88 could not use the same stock exhaust as the coup 88 because they figured that the "vert" occupants could not handle the noise. they are/were probably correct!...i have quite a bit of resonance in my 88 and have to turn the radio up quite a bit to hear it!..man, that sucks!
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Old 08-21-2007, 10:47 PM
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Originally Posted by LD85 View Post
This is so simple that it is ridiculous, but I guess people want some off the shelf solution. But it works, nuff said

http://forums.corvetteforum.com/show...hlight=altered

Why was your thread locked?
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Old 08-21-2007, 10:54 PM
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Someone asked how the stock exhaust would handle the resonance created by headers. Well, I have headers going into the stock LT4 exhaust and I got resonance from this. It isn't much resonance but it bothers me, sounds a little too much like a truck for my tastes. I'm sure the lack of cats and the resulting increase in sound is mostly to blame. So the stock exhaust is not a magic solution to resonance, if you've got too good of flow going into it.
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Old 08-21-2007, 11:00 PM
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In that thread where they shoved steel wool into the muffler, nobody answered the question about it being flammable. Is the steel wool a fire hazard?
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Old 08-21-2007, 11:28 PM
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Originally Posted by LouisvilleLT4 View Post
In that thread where they shoved steel wool into the muffler, nobody answered the question about it being flammable. Is the steel wool a fire hazard?

I have pulled the steel wool out and looked at it 2-3 times, and you get carbon on the outside of th Steel Wool, nothing else, if you unwrap the Steel wool, the inside is still normal.

Questions to ask, at what temp does Steel Wool become flammable i.e. what is the Steel Wool flash point?

Doing GOOGLE, it looks like 121-C / 250F,, so exhaust at 250F, I doubt very very highly that the exhaust reaches this temp at the exit of the muffler.

http://www.utrechtart.com/msds/docs/CPLO.pdf
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Old 08-22-2007, 12:36 PM
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Originally Posted by BerniesVette View Post
Has anyone tried running the center resonator with muffler eliminators to see how that sounds?
Bernie
Yes, and it was loud. Acceleration was an attention getting experience. Not that it was all bad, but a little too much for me. So, I replaced the resonator with a Magnaflow dual in/dual out muffler. The Magnaflow has an x-pipe built into it and the casing is packed with sound absorbing material. I wish I had a sound clip for you, but the end result is a very muscular sound. Resonance is low and I think that low end torque is a little snappier. All I know for certain is that I am addicted to the sound and have received compliments from many.

Cat forward is bone stock, and the muffler was hooked up to factory pipes. The Magnaflow was under $100.
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