Rattle/Rasp After JDL Catted UEL Header Install
 

So I've searched endlessly and I'm at a loss at what's causing this sound.

I picked up a JDL Catted UEL header for their black friday deal and overall I love how it sounds paired with my Nameless resonated and catted FP/OP and Nameless axleback.

My issue is after the install I developed this rasp/rattle which no one has been able to identify. I've been told that it's just what high flow cats sound like. I had two shops check it for me and they said there are no leaks after I checked it myself. I tried replacing the OP > Header gasket to see if that would fix it and I'm still getting this sound. It only occurs under high load once it gets to around 4-5k RPM. It makes me not want to drive my car hard at all because I hate the sound.

Any ideas what it could be? The only thing I haven't done yet is get under the car with someone else revving it so I could isolate where exactly it's coming from. I've never heard this sound coming from other video clips.

[ame="https://www.youtube.com/watch?v=LK82fw2yCos"]VIDEO CLIP[/ame]

I had this same, or very similar, noise w/ my JDL EL header paired w/ a Greddy Supreme SP catback. I checked my gaskets and contact points several times after installing, because I thought it always sounded like metal contacting metal and/or a leak. I encountered this sound briefly between 3200 and 4000 under medium to high load; after 4k the sound was gone.

I added an overpipe --this may have helped a little, but not much.

I wrapped my header/overpipe --may have quieted down the header, but did nothing for the metallic rasp sound.

I swapped out the oem front pipe for JDL's Ultra-quiet catted front pipe --this helped. It shrunk the window of revs where I was hearing this noise, and changed it. The rasp was still there, but now the car sounded angrier:)

Finally, I replaced the JDL front pipe with a Fujitsubo double resonated front pipe. Finally, all that rasp sound was GONE. 100% GONE. But, now my car smelled like a catless car, and lost it some of the character in it's exhaust note. Also, w/ the catless Fujitsubo front pipe, the car was noticeably quieter than the JDL UQFP --i'd say it was like the OEM pipe, minus all the rasp.

I have a similar sound with my catless EL 4--2-1 headers. They are coated. It happens in a small window around 3k till 3800. Bit more purnocued when the car is cold. When the car is warm I mostly can't hear it. I have a stock OP, modified OE FP with cat and switched resonator by vibrant and a mxp sp CB. Car is very quiet and the wine from the SC is very noticeable.

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Similar sound with the JDL 4-2-1 here. I also initially thought it was a leak, and I may have had one, but even after completely re-torquing the system and checking for leaks the sound is still there. My current theory, based on what some other posters have said, is that the collector design of this header just has some flow dynamics that interact poorly with most front pipe configurations / resonator positions. I will probably swap over to a JDL UQFP (and maybe weld in an additional res? I don't think there are any catted + dual res FPs out there) to try to mitigate.

I think your right on with your theory. It's a metallic tone right?

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Yeah, sounds pretty much exactly like the video in the OP. Not really noticeable in the cabin, but pretty rough with the window down and driving near a wall. 2.5k - 3.5k RPM range.

I've got the JDL EL catted headers. Same sound from it. Was even more noticeable when I was using the Berk FP. I moved on the the JDL FP, it has helped. Instead of getting that same reverberating sound between 3400-5200 rpms, it narrowed the noise down to about 3800-4200 rpms.

Yup notice the same as well.

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Check your header to skid plate clearance especially on the right side. It could be rattling and or getting close enough to reverberate off of the skid plate under load. Typically sounds like a metallic exhaust leak between 2500-3500rpm under load. The engine rocks to the right and the header will move at least an inch down closer to skid plate. So it might look like it has plenty of clearance when it really doesn’t. Mine made a weird noise between that rpm. Used a rubber mallet put the skid plate on a barbell plate, and hammered it into the hole to “bubble” it down giving another inch of clearance. Fixed my noise. Worth looking into at least.

I suspected this at first but the sound is still there even with the skid plate completely off.

IT seems as something inside the resonator or cat part of your FP is loose and creates this rattle, try fit the OEM FP and see what happens!

This is what I'm suspecting since I didn't have this issue with the stock header. Until I get under the car with someone else revving it I won't be able to isolate it, I just know it's coming from the front and it sounds like some other people have the same experience until they get the right front pipe to work with their system.

3" Berk catted - custom resonated front pipe, hope it will remove any rasp/rattle - as in your case - due to OEM catback:

https://oimg.photobucket.com/albums/...pskw3sygcu.jpg

https://oimg.photobucket.com/albums/...psl32rrw70.jpg

Where did you get that resonator?