New headers in, but what's this???
03-09-2006, 06:54 AM
#1
Melting Slicks
Thread Starter
New headers in, but what's this???
I recently had LT headers/cat/xpipe installed. Now I have a wicked resonance/vibration/buzz that goes through the whole car (and eardrums) at about 3500 rpms. I've had a Borla Quad cat back for a couple years, and never had any resonance problem. Anyone ever experience this? I still have the stock cat-back. Maybe I'll try to swap it back to see if it goes away. 
03-09-2006, 09:29 AM
#3
Burning Brakes
Check to be sure you have clearance from other structures from the headers all the way back to your mufflers, sounds like the pipes are buzzing against something.
03-09-2006, 09:34 AM
#4
Le Mans Master
Originally Posted by Just Enough
Check to be sure you have clearance from other structures from the headers all the way back to your mufflers, sounds like the pipes are buzzing against something.
03-09-2006, 09:48 AM
#5
Melting Slicks
Thread Starter
I double checked the clearance on a lift. No contact anywhere. It's a very professional installation. I don't want to name the header yet, beause I'm sure the installer will correct the problem. If it can't /won't be fixed, I'll elaborate. I was hoping someone had seen this and had a fix.
03-09-2006, 10:07 AM
#7
Le Mans Master
With stock cat back you should not be hearing resonance like that. With stock cat backs even with headers and no cats it should sound fairly quiet with no resonance.
Sounds like the system is loose, but you said you checked it. This is a strange one. I have heard of the internals on cats coming loose and causing noise but that is usually a rattle or clicking sound.
It really does sound like it is setting against something or loose.
Sounds like the system is loose, but you said you checked it. This is a strange one. I have heard of the internals on cats coming loose and causing noise but that is usually a rattle or clicking sound.
It really does sound like it is setting against something or loose.
03-09-2006, 10:44 AM
#8
Safety Car
Double check your clearance. Especially the passenger side where it goes over the axle. I had something similar and the pipe was touching the differential. There is not much room there at all.
03-09-2006, 01:52 PM
#9
Racer
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Is it from outside the car or inside?
I have a wild buzzing noise in the passenger compartment at that RPM after I installed my headers. It is coming from the driver side, rear speaker grill/trim/assembly.
I have a wild buzzing noise in the passenger compartment at that RPM after I installed my headers. It is coming from the driver side, rear speaker grill/trim/assembly.
03-09-2006, 02:18 PM
#10
Drifting
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Cruise-In IV Veteran
Cruise-In V Veteran
Originally Posted by EdsC5
I recently had LT headers/cat/xpipe installed. Now I have a wicked resonance/vibration/buzz that goes through the whole car (and eardrums) at about 3500 rpms. I've had a Borla Quad cat back for a couple years, and never had any resonance problem. Anyone ever experience this? I still have the stock cat-back. Maybe I'll try to swap it back to see if it goes away.
Had the same exact problem with my C4 after installing headers, and a new Corsa Catback with Random Tech mini cats.
After speaking with one of the techs at Corsa, I was informed that there was a reason why Corsa placed the resonators where they are on an unmodified system. And that is, to remove the resonance which occurs at that precise spot in the pipes.....some sort of mathematical formula that's beyond my feeble mind is used to arrive at that conclusion.
After explaining just what I had for an exhaust system and the exact measurements of where each component was located, he suggested that the Random Tech mini cats be moved downstream such and such a distance, and after having done so, the nasty WOT resonance at 3500 rpm virtually disappeared.
Just for what it's worth.
03-09-2006, 08:39 PM
#11
Pro
Originally Posted by EdsC5
I recently had LT headers/cat/xpipe installed. Now I have a wicked resonance/vibration/buzz that goes through the whole car (and eardrums) at about 3500 rpms. I've had a Borla Quad cat back for a couple years, and never had any resonance problem. Anyone ever experience this? I still have the stock cat-back. Maybe I'll try to swap it back to see if it goes away.
03-09-2006, 09:44 PM
#12
Melting Slicks
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CI 6-7, 9-10 Veteran
Originally Posted by Just Enough
Check to be sure you have clearance from other structures from the headers all the way back to your mufflers, sounds like the pipes are buzzing against something.
I had this happen to me, minor adjusting and all was fine. Are your connections welded together?? If not, the clamps may be the cause also. Good luck
03-10-2006, 05:56 AM
#14
Melting Slicks
Thread Starter
The problem does appear to be in the cats. When you tap on the right side cat there is an obvious tinny sound, like something broken internally. (Sort of sounds like a metallic snare drum) We're going to check it out next week. Thanks for all the responses. It's also throwing numerous HO2S codes for all four sensors. Have to double check all wiring, etc.
03-10-2006, 08:57 AM
#16
Safety Car
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Originally Posted by EdsC5
The problem does appear to be in the cats. When you tap on the right side cat there is an obvious tinny sound, like something broken internally. (Sort of sounds like a metallic snare drum) We're going to check it out next week. Thanks for all the responses. It's also throwing numerous HO2S codes for all four sensors. Have to double check all wiring, etc.
