Collapsed Cat?

[mystery_kid]

recently i put an r34 gt-t turbo in my r32gts-t

anyway since then i've had this odd sounds, it kind of sounds like it could be an exhaust leak or something rattling even

it loudest from under the passenger side door, but you can hear it a bit in the engine bay

at first i thought it was an exhaust leak from the joint in the exhaust between the front pipe and cat

i can confidently say that isn't the problem after replacing the gasket and bolts and what not

at first i instantly thought it was an exhaust leak from a turbo gasket but i have been over these and they certainly do no appear to be leaking all the nuts and bolts are done up tight the head to exhaust mani gasket has also been replaced a bit less than a year ago. (all gaskets were replaced with legit nissan items)

this sound is driving me insane, i'm now left thinking has my cat collapsed? could shit be rattling around inside of it because it sounds like it when i lay under the car

the cat isn't anything special it's been welded onto the exhaust on the outlet side of it because the exhaust is 3.5" and the front pipe is 3" the cat is either stock or something but it's 3"

is it even possible to have something rattling around in a cat? i'll admit i don't really know what goes into one

Thanks

Dan

ps. as far as losing power that goes with a cat dying etc, it does come on boost fairly late i realise it's a bigger turbo but it's dead set not full boosting until around 4500rpm for 0.8bar

[mad082]

the r34 turbo on an rb20 will boost at pretty high rpms. that's just the joys of owning the lag monster that is the rb20. 4500rpm might be a touch high though.

if the cat was collapsed then it may rattle, but you would also find that boost at high rpm would start to drop off.

also i would recheck all the manifold studs. make sure none are broken. other than that the only other real possibility is that the turbo is stuffed.

[mystery_kid]

i had all the studs replaced and helicoiled when i destroyed the thread for a couple of them inside the head

so they are all new

yeah i'm aware it will have some lag, that 4500rpm was a figure i had from just after i put the turbo on.

tbh i think it's even later now after i did a track day a few weeks ago and the sound that i think is the cat has kinda gotten a bit worse too

[GT-R32]

Tap your cat with a broomstick or something and if it sounds like it's full of sand... It's collapsed.

[Sparky206]

What was the reason for the new turbo?

Reason i ask is if you blew the exhaust wheel off the old one, then it WILL be sitting there in pieces at the front of your cat