Everytime i start my car i hear a rattle type sound which i thought was coming
from under the hood, today i finaly decided not to be lazy and check it, well
it sounded like it wasn't coming from under the hood, and i listen under my car
and i hear this weird sound coming from around my cat, really odd sound, like i
have an exhuast leak, im almost 100% postive that the cat is original, and
everyonce in a while when idleing i can hear a rattling under the passenger
side of the car, should i replace my cat, also wut kind should i get?

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88' GTA 350 MODS---> air foil, K&N, Shift Kit, 180* therm, TB bypass

 

I am having the same problem u are my cat rattles and leaks especially when I first start it. Right now am thinkin about dumpin the cat but that could hurt emissions. (but i might still do it anyway)Another option is to order a high flow cat(I think dynomax makes one) from jegs or summit, that could solve the problem, and give u a little better performance.

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I Love Smokin Tires
(stangs fear me)

 

My car rattled when I was stopped in drive. When I put it in neutral the rpms smoothed out and the rattle went away. Turned out that my heat shield on my cat had rusted apart and the top and bottom were rattling against each other.

 

a real ghetto way to fix the cat heat shield rattling is to take a few stainless hose clamps, and attach them to each other making one big clamp that is long enough to go around the whole cat. then just tighten it down and voila...heat shield rattles are over.

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=====================
1992 25th Anniversary z28 Convertible

 

hehe mine rattled too but it was "only" 115k miles old...something else was wrong somewhere in my exhaust because the sound coming out of the pipe made some wierd *** noises too...

 

You can get a catco cat from summit for $50. Its about 6" shorter than stock, so just buy a piece of pipe the same diameter. My catco cat was 3" ID so the 3" pipe slid right in. We cut the flange off my cat-back and put a 3" ID to 3" ID connector on the two and it worked great.

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Chuck Kulchar
1991 RS
Open Element w/K&N
3.42 - posi - disc
3" cat and Force II cat-back

 

its not the heat shield, its on tight, but do u guys think i should guy my cat? if so wut exactly do i do, just take it off and punch out all the stuff? i have another year before emissions, and i'll either sell the car back to my uncle or replace the cat before i get it tested? is there any disadvantages to gutting a cat?

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88' GTA 350 MODS---> air foil, K&N, Shift Kit, 180* therm, TB bypass

 

Simply put, yes. To gut a cat all you do is take it off and knock the insides out. Then if you have a carb set the A/F a little richer. I'm getting ready to hollow mine when my flowmaster comes in. The sound is much better (in my opinion) with a hollowed cat, then when it comes emmisions time you can slide a high flow cat on there.



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Matt

1984 Camaro Z28
-'78 350 with Edelbrock 600 Carb, Edelbrock Preformer RPM Air gap intake, ACCEL plugs & wires, 14" Accel filter.
-TH350 with Hurst Pro-matic shifter & B&M Street shift kit.
-Audiobahn single 12" Sub powered by Sony Xplode amp, Farenheit 6x9" & 4x6" speakers, with a Sony Xplode headunit.
- Eagle Alloys 15" Alum. Rims surrounded by P235/60R15 BF Goodrich Radial T/A's

 

Yea especialy with 200k on the cat you should defenetly replace it. The avarage life span is around 60k so you got your moneys worth .
But when you do replace/remove it you will think you got a 454 under the hood because that thing is full of crap and is choking performance.
SSC

 

where should we order? me too i got a bad cat....


decnet price for what to get..

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91 FireBird 305 V-8
Edelbrock Catback, Fourth Gen Console. i have six cupholders. all for starbucks!
ghetto rigged cold air intake,
GheTTo Riggers INC.
We Make Mcgyver look Like Crap
God Created The Earth, And Then Turned Up The Bass

 

i just learned that my cat was already gutted, talked to my uncle who owned the car behind me, and he said when he got it, it was already gutted.

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88' GTA 350 MODS---> air foil, K&N, Shift Kit, 180* therm, TB bypass

 

stoopid cat,

Mines welded on.. WTF with a U Bolt over it,

Dmnnn. iwth some pipe comming out, any of you got any recommendations...

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91 FireBird 305 V-8
Edelbrock Catback, Fourth Gen Console. i have six cupholders. all for starbucks!
ghetto rigged cold air intake,
GheTTo Riggers INC.
We Make Mcgyver look Like Crap
God Created The Earth, And Then Turned Up The Bass