The Official Exhaust Resonance Post!
#1
Melting Slicks
Thread Starter
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...
If you have successfully limited or eliminated resonance please share your technology...
#2
Race Director
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.
#3
Le Mans Master
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'm curious to see what people put for their aftermarket setups and how much resonance it causes.
#4
Team Owner
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C7 of the Year - Unmodified Finalist 2021
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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.
Otherwise unless you get a particular catback that doesnt have it or doesnt have much, you'll be stuck with it.
#5
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St. Jude Donor '08-'09
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.
I just finished adding even more.
True duals with teh flows on the end.
noisy as F and sounds like a cobra at WOT.
#6
Melting Slicks
Thread Starter
You are right, I stand corrected, it should be the anti-resonance post. Maybe we can put together a Cabelas group buy on earmuffs?!
#7
Melting Slicks
Thread Starter
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.
#8
Race Director
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.
#10
Safety Car
#11
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St. Jude Donor '05
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 $$ if I got rid of the 3" pipes it would quiet down. Resonates inside, quiet outside.
2-Cats will dumb the sound down a bit as will manifold vs headers
2-Hangers-Use a rubber bushgin if you can so its not 100% solid mount. less transmits through the body
3-Smaller pipes, less resonance-Larger pipes slows down the exhaust gases, they spend more time tumbling around in the pipe. Low frequency vibrations.
4-Rolled tip muffs (referring to the edges of the muffler case) -Typically have some "give" to them to expand with increasing exhaust pressure. Welded muffs typically dont and almost always have no packing in them either that will absorb sound. .
5-Typically the bigger cased muffler the quieter they will be.
6-Buy a Buick
Having 2 dynomax super turbos (typically a quiet muff) and 2 inline dynomax "bullets" my car should be quiet inside..Its not. I bet $$ if I got rid of the 3" pipes it would quiet down. Resonates inside, quiet outside.
Last edited by cv67; 08-21-2007 at 06:03 PM.
#12
Race Director
#14
Race Director
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
http://forums.corvetteforum.com/show...hlight=altered
#15
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'm curious to see what people put for their aftermarket setups and how much resonance it causes.
#16
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
http://forums.corvetteforum.com/show...hlight=altered
#17
Drifting
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.
#19
Race Director
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
#20
Le Mans Master
Cat forward is bone stock, and the muffler was hooked up to factory pipes. The Magnaflow was under $100.