Yet another exhaust question
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2nd Gear
Joined: Oct 2005
Posts: 2
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Yet another exhaust question
I have a 1988 C4 convertible and have recently installed the magnaflow SS system on it. Like others on here it has exhibited the dreaded resonance at about 1800 RPM. 
I need an alternative that is quiet on the inside. I can change out the whole system and sell this one at a loss (anyone interested let me know....make a sweet deal on it...less than 200 miles on it). or I can keep the Y-pipe and change out the mufflers. Any thoughts or ideas on something quite, yet looks good please advise.
Mike
I need an alternative that is quiet on the inside. I can change out the whole system and sell this one at a loss (anyone interested let me know....make a sweet deal on it...less than 200 miles on it). or I can keep the Y-pipe and change out the mufflers. Any thoughts or ideas on something quite, yet looks good please advise.Mike
Safety Car
Joined: Aug 2004
Posts: 4,908
Likes: 735
From: Southwest Kansas
2022 Corvette of the Year Finalist -- Unmodified
2021 C6 of the Year Winner - Unmodified
Well, I guess I'll be the first to come on here and say "Corsa". It seems that if you want No resonance it has to be Corsa. They are proud of there stuff, but they do not have that resonance of the other systems. (Flame suit on)
There will be people come on here and say that "their" system doesn't have have any resonance and there will be other who claim that those systems do have it. But the only one that I have read on here, who without a nay vote, claims no resonance, is Corsa. You might get lucky and not have any resonance with some other system, but I'd almost guaranttee none with a Corsa. And the systems for the L98 are less expensive than the LTx versions.
I bought mine from TBryne during the group purchase they offered this summer.
There will be people come on here and say that "their" system doesn't have have any resonance and there will be other who claim that those systems do have it. But the only one that I have read on here, who without a nay vote, claims no resonance, is Corsa. You might get lucky and not have any resonance with some other system, but I'd almost guaranttee none with a Corsa. And the systems for the L98 are less expensive than the LTx versions.
I bought mine from TBryne during the group purchase they offered this summer.
Melting Slicks
Joined: May 2003
Posts: 3,490
Likes: 68
From: Hewitt NJ
Originally Posted by rugby!
i went from stock (to quiet) to magnaflow (way to load) to corsa (just about right) i am very happy with the corsas. try them i think you will be happy
Le Mans Master
Joined: May 2005
Posts: 5,214
Likes: 65
From: Queensland, AUSTRALIA
did it sound anything like this?? Im not familiar from the system you described.
http://videos.streetfire.net/player....9-0497EA6C1586
the one in this clip is loud outside, but was nice and quiet at highway speed, ONLY AFTER i did what im now doing on my 94, and no resonance after i did the rear compartment (see thread link below) Might be cheaper than changing exhaust again.
http://forums.corvetteforum.com/show...39&forum_id=34
http://videos.streetfire.net/player....9-0497EA6C1586
the one in this clip is loud outside, but was nice and quiet at highway speed, ONLY AFTER i did what im now doing on my 94, and no resonance after i did the rear compartment (see thread link below) Might be cheaper than changing exhaust again.
http://forums.corvetteforum.com/show...39&forum_id=34
Team Owner
Joined: Dec 2000
Posts: 90,675
Likes: 304
From: SE NY
Cruise-In II Veteran
While investigating the issue on my '88 I found that the hatch fiberglass panels seem to have a natural frequency of around 20-30Hz, which amplifies the sound generated by some exhaust systems.
So, you have several optins:
-replace the exhaust system with one that generates lower sound level in the "resonance" frequency range
-install sound deadening (like Dynamat) in the rear hatch to reduce the transmitted sound level
-find a way to lower the natural resonant frequency of the fiberglass flooring in the hatch area.
To see what I mean, put your had under the carpet in the hatch and do a little brake stand. You will feel the strong vibration of the panels that enhance the exhaust sound at that frequency. Yea, I know, that's why it's called "resonance"...
So, you have several optins:
-replace the exhaust system with one that generates lower sound level in the "resonance" frequency range
-install sound deadening (like Dynamat) in the rear hatch to reduce the transmitted sound level
-find a way to lower the natural resonant frequency of the fiberglass flooring in the hatch area.
To see what I mean, put your had under the carpet in the hatch and do a little brake stand. You will feel the strong vibration of the panels that enhance the exhaust sound at that frequency. Yea, I know, that's why it's called "resonance"...
