[SpyderSoldier]

Hello everyone,

I was wondering if the secondary cats function as resonators that dampen vibrations? Bc I was getting this vibration/resonance pitter patter sound towards the trunk after getting my secondary cats deleted, not sure if I need to go to an exhaust shop to get this checked out/or what my solutions are. I still have my secondary cats handy, but I don't wanna get the volume decreased again haha
Let me know if anyone had this issue with their secondary cats.
Attached video of the sound below:
https://youtu.be/u0pijSuOsTc

[Megahurtz]

sound creates vibrations.........louder sound, more vibrations........

[MT-SS1LE]

Originally Posted by SpyderSoldier

Hello everyone,

I was wondering if the secondary cats function as resonators that dampen vibrations? Bc I was getting this vibration/resonance pitter patter sound towards the trunk after getting my secondary cats deleted, not sure if I need to go to an exhaust shop to get this checked out/or what my solutions are. I still have my secondary cats handy, but I don't wanna get the volume decreased again haha
Let me know if anyone had this issue with their secondary cats.
Attached video of the sound below:
https://youtu.be/u0pijSuOsTc

I've been thinking about doing this. How much louder is it without the secondary cats? Any noticeable power gain?

[GreyGhost702]

Sweet vibrations. I had a terrible "clicking" noise after firing up the car with the new build. Dealt with it 'til I had the engine break-in completed. Set the car on jack stands outside one day and fired it up so I could slide myself on a creeper under the car while it was running so I could locate the offending sound. Just go at it with a 12" socket extension touching virtually everything that looked like it might have movement. I did some small 1" x 1" square adhesive heat shielding as padding on the back sides of some of the metal heat shielding under the car, as I found they were "buzzing" a bit and this softened the connection to the chassis well and I don't have to worry about it melting. The clicking under the car wasn't as pronounced and had a really hard time hunting it down. I thought it might be the NPP valves clicking so I stuck a longer extension up there and didn't have enough effect. There's all kinds of heat shielding around the muffler area and connectors and shit, I still need to go over those. But as I reached my hand around the rear bumper to reposition myself I grabbed the edge of the license plate and the clicking stopped. So it turned out the license plate was vibrating with the cam. A touch of doubled sided 3M here and there, screw the plate back on, no more clicks.

Now that I have driven the car for a while and put a lot of WOT time on the car, I have developed yet another "chirp" I need to hunt and kill, but it sounds like a spring time job.

I suggest the same approach, get the car off the ground safely by whatever method you can so that you can get under there and touch stuff until you find the offender. You'll probably find things along the way that are making noises you aren't hearing in the cabin, as well. Heat shielding is often a noise maker when it picks up the right frequencies or you start shaking the car. Adhesive heat shielding is cheap (relatively) and will help dampen vibrations and is very wear resilient. You can slide this stuff behind cables and stick it to the chassis to keep connectors from vibrating against the car, all kinds of clever ways to apply it.

Your sound almost sounds like it's in the trunk itself. But sounds are a PITA to locate sometimes. I thought my click was under the car, and it was the damn license plate. You really have to feel around for it and molest your car.

[SamSmoothCastel]

Secondary Cat Delete + Borla ATTAK NPP = Worth every penny

[tortilla-flats]

Is your exhaust hitting the tunnel cross over?

[KingLT1]

Originally Posted by Megahurtz

sound creates vibrations.........louder sound, more vibrations........

Mind Blown!!

[Dynamical]

Racecah problems

[SpyderSoldier]

Originally Posted by GreyGhost702

Sweet vibrations. I had a terrible "clicking" noise after firing up the car with the new build. Dealt with it 'til I had the engine break-in completed. Set the car on jack stands outside one day and fired it up so I could slide myself on a creeper under the car while it was running so I could locate the offending sound. Just go at it with a 12" socket extension touching virtually everything that looked like it might have movement. I did some small 1" x 1" square adhesive heat shielding as padding on the back sides of some of the metal heat shielding under the car, as I found they were "buzzing" a bit and this softened the connection to the chassis well and I don't have to worry about it melting. The clicking under the car wasn't as pronounced and had a really hard time hunting it down. I thought it might be the NPP valves clicking so I stuck a longer extension up there and didn't have enough effect. There's all kinds of heat shielding around the muffler area and connectors and shit, I still need to go over those. But as I reached my hand around the rear bumper to reposition myself I grabbed the edge of the license plate and the clicking stopped. So it turned out the license plate was vibrating with the cam. A touch of doubled sided 3M here and there, screw the plate back on, no more clicks.

Now that I have driven the car for a while and put a lot of WOT time on the car, I have developed yet another "chirp" I need to hunt and kill, but it sounds like a spring time job.

I suggest the same approach, get the car off the ground safely by whatever method you can so that you can get under there and touch stuff until you find the offender. You'll probably find things along the way that are making noises you aren't hearing in the cabin, as well. Heat shielding is often a noise maker when it picks up the right frequencies or you start shaking the car. Adhesive heat shielding is cheap (relatively) and will help dampen vibrations and is very wear resilient. You can slide this stuff behind cables and stick it to the chassis to keep connectors from vibrating against the car, all kinds of clever ways to apply it.

Your sound almost sounds like it's in the trunk itself. But sounds are a PITA to locate sometimes. I thought my click was under the car, and it was the damn license plate. You really have to feel around for it and molest your car.

Thanks dude. Ya I took it into the dealer and they worked w the intermediate heat shield and mentioned it had a bit of play. But it didn’t d anything to the sound, they proceeded to blame the lack of the secondary cats as there’s nothing to dampen that vibration and it’s causing the resonance lol.

I think it might be the muffler or something above it, as I checked all along the inside of the trunk and there’s nothing loose there

[Ventmaster]

OP my car makes a similar sound. It comes and goes but is most prevalent at steady cruise 30-40mph at low RPM (like 1500). It's been driving me a little crazy! Anyway, thanks to GreyGhost's post I checked my license plate and realized I have a plastic frame around it (actually I knew it was there-it kind've implies I might be a member of law enforcement, but likely doesn't fool anyone), that could be the source of my creaky/squeeky/crackling sort of sound. Just put some 3M on it and got my fingers crossed hard! It can't be that easy... can it?
Please keep us updated if you discern where your noise is comimg from.

[Patriot Motorsports USA]

Originally Posted by tortilla-flats

Is your exhaust hitting the tunnel cross over?

That was exactly what I was thinking!! If you watch the video I just posted, I removed my cats but installed the Magnaflow resonated-X with massive results and ZERO noise or drone!

[SpyderSoldier]

Originally Posted by Ventmaster

OP my car makes a similar sound. It comes and goes but is most prevalent at steady cruise 30-40mph at low RPM (like 1500). It's been driving me a little crazy! Anyway, thanks to GreyGhost's post I checked my license plate and realized I have a plastic frame around it (actually I knew it was there-it kind've implies I might be a member of law enforcement, but likely doesn't fool anyone), that could be the source of my creaky/squeeky/crackling sort of sound. Just put some 3M on it and got my fingers crossed hard! It can't be that easy... can it?
Please keep us updated if you discern where your noise is comimg from.

Okay update! I just took my car into my stereo shop to get some sound deadening around my dashcam wires & I mentioned the sound to them. So they took a while localizing the sound, turns out its a flappy fender liner vent that comes loose over time due to resonance from NPP/loud exhaust systems and causes a kind of tinging noise! They tightened it and added sound deadening on it, whisper quiet now. Been ignoring it for 6 months and it was driving me crazy haha

I had taken it to a muffler shop yesterday assuming it was an exhaust concern but they tested it, whacked it all over and was not replicating that sound. No leaks were noted either. That's how we figured it was a trim issue

[Hostile_1LE]

Originally Posted by SpyderSoldier

Okay update! I just took my car into my stereo shop to get some sound deadening around my dashcam wires & I mentioned the sound to them. So they took a while localizing the sound, turns out its a flappy fender liner vent that comes loose over time due to resonance from NPP/loud exhaust systems and causes a kind of tinging noise! They tightened it and added sound deadening on it, whisper quiet now. Been ignoring it for 6 months and it was driving me crazy haha

I had taken it to a muffler shop yesterday assuming it was an exhaust concern but they tested it, whacked it all over and was not replicating that sound. No leaks were noted either. That's how we figured it was a trim issue

where exactly is the fender vent?

[SpyderSoldier]

Originally Posted by Hostile_1LE

where exactly is the fender vent?

Sorry for the late response as I had just gotten back from the holidays. But they mentioned they had to take the entire trunk liner apart on either side to access it, almost close to the wheel well area. It's an absolute pain to get to, but if you can take it to any stereo shop that deals with sound deadening, they may be able to help you. I also think the dealer should too (but i have terrible experiences there as they blame everything on unrelated mods) as long as you just point them in that direction.

I think resonance tends to loosen things over time especially with any custom exhaust work so no wonder I saw this only 2.5 years after owning the car. All fixed though! Finally can just enjoy the drive, this rattle was driving me crazy for the past 6 months lol