The Official Exhaust Resonance Post!
08-22-2007, 08:09 PM
#22
Team Owner
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St. Jude Donor '05
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.
No worries
08-22-2007, 09:02 PM
#23
Race Director
A bag of Steel Wool cost be $1.99 at Home Depot, I take 4-pieces and unroll two of them and wrap them around the other two pieces, the push it into one side of the exhaust.
So this is the end result, resonance gone,, lost maybe 2-5 hp,,,
for me no issues,
Reversible, pull it out when you go to the track but on the street, you wont miss 2-5 hp.
So this is the end result, resonance gone,, lost maybe 2-5 hp,,,
for me no issues,
Reversible, pull it out when you go to the track but on the street, you wont miss 2-5 hp.
09-07-2007, 01:43 AM
#27
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St. Jude Donor '05
its a short exhaust system to begin with and mufflers being the exit with no tailpipe afterwards makes the chances of resonance real high if something is changed.
09-07-2007, 01:44 AM
#28
Le Mans Master
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St. Jude Donor '03 & '05
Of course gears help, as you will not be in that rpm range often
09-07-2007, 07:28 AM
#29
Le Mans Master
I have two Magnaflows with stock resonator and stock cats with the tipe extended past the bumper. I do have resonance at 1000-1500 rpm's.
Last edited by runner140*; 09-07-2007 at 07:31 AM. Reason: correction
09-07-2007, 07:50 AM
#30
Melting Slicks
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Hey lt4obsesses,
I had a local shop remove my mufflers and the sound is great but the resonance is terrible in city traffic. You wouldn't have the part number of the magnaflow muffler you used would you? I think that is what I need!
Bernie
I had a local shop remove my mufflers and the sound is great but the resonance is terrible in city traffic. You wouldn't have the part number of the magnaflow muffler you used would you? I think that is what I need!
Bernie
09-07-2007, 08:29 AM
#31
Melting Slicks
Why couldnt Chevrolet just have come up with something like they did in 1962 called Off road exhaust system, and just give C4 and C5 owners a specific sound which would stop all this tension of trying to get their exhaust system right.The closest I ever heard a car have that specific old Corvette sound was my sons 85 Z28 with headers and one flowmaster muffler which sat in front of the rear axle, And there was NO resonance at all. My 84 has flowmaster 40s with gutted cat and does not sound as good as his car and the resonance is very loud.His did have a 305 if that makes any difference?
09-07-2007, 10:54 AM
#32
Le Mans Master
Does anyone know if switching to the mass backed carpet replacements from wilcox helps with the insulation? Or do you really need a layer of acoustic insulation in there too? I really think dampening the sound in the interior is a large part of the key to reducing resonance. The interior on my '85 transfers so much sound on the highway and I know a lot of it is road noise too, not just exhaust.
09-07-2007, 11:03 AM
#33
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St. Jude Donor '05
Mass backing will definitely help as opposed to not having it.
Magnaflows will still resonate btw.
Magnaflows will still resonate btw.
09-09-2007, 03:24 PM
#35
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St. Jude Donor '05
Resonance between 1100-2000 is bad. Even in this clip when Im just crusing the rpm range is well above that and still booms...
This is with dual 3's, dual dynomax "bullet" resonators and Dynomax super turbos. Bet with a smaller pipe it would be more manageable.
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This is with dual 3's, dual dynomax "bullet" resonators and Dynomax super turbos. Bet with a smaller pipe it would be more manageable.
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09-09-2007, 04:07 PM
#36
Drifting
About the steel wool trick... doesn't steel wool rust like crazy when you have it in a hot, occasionally moist place like the mufflers? Wouldn't that rust spread to the mufflers? Or is there some sort of "stainless steel wool" you can buy?
09-09-2007, 06:49 PM
#37
Intermediate
steel wool installed
I tried the steel wool trick years ago. On my car, I had a set of smittys and scavenger pipes, and got a noise ticket. So I poked steel wool up the pipes, (drilled holes in the pipes to hold the wool in them) and drove to the other town to get signed off. It worked, and Man it was quiet!! It was neat dark when I left and so I pushed it up to the neat triple mark. I passed this car, and got about 50 feet ahead of him, and two great big ***** of burning steel wool rolled out and scared the living crap out of us. Yes steel wool will get hot and glow from really hot exhaust. That my lesson
09-09-2007, 09:02 PM
#38
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Why couldnt Chevrolet just have come up with something like they did in 1962 called Off road exhaust system, and just give C4 and C5 owners a specific sound which would stop all this tension of trying to get their exhaust system right.The closest I ever heard a car have that specific old Corvette sound was my sons 85 Z28 with headers and one flowmaster muffler which sat in front of the rear axle, And there was NO resonance at all. My 84 has flowmaster 40s with gutted cat and does not sound as good as his car and the resonance is very loud.His did have a 305 if that makes any difference?
and dual outputs to run to the back. It would be similar to a eliminator setup with one muffler. Would that be too restrictive?
09-09-2007, 09:18 PM
#39
Race Director
crossfire84 = "two great big ***** of burning steel wool rolled out and scared the living crap out of us. Yes steel wool will get hot and glow from really hot exhaust. That my lesson"
No way your exhaust got up to 250f