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Cutting out Catalytic Converters

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Old Oct 13, 2010 | 01:03 AM
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Default Cutting out Catalytic Converters

I have a 2002 Pontiac Trans Am WS6. I am wondering if anyone has had their catalytic converters cut out and run just straight pipes. The guy I talked to at the exhaust shop said that he could do this for 240$, including the O2 simulators that would need to be put on so the SES light would not come on.

However, he said if I had a performance muffler, that my exhaust, post catalytic converter removal, would be somewhat louder and that I would hear a deceleration popping. I don't think I would like this popping noise he is talking about. At this point, my only options are to either have them cut out or pay to have the converter replaced, which is more expensive. I can't afford a new exhaust system (e.g. Borla).

I'm curious if anyone has any experience or knowledge on this subject. Thanks.
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Old Oct 13, 2010 | 02:23 AM
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Do it
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Old Oct 13, 2010 | 07:43 AM
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$240? Ouch. Even with stock manifolds, it shouldn't be that hard to bend some pipe up, but a flange on the manifold side, and install them.
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Old Oct 13, 2010 | 11:55 AM
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My brother just took off his cats, took a crow bar and stabbed the insides of them until all the cat material broke up and fell out and then reinstalled them and bought 02 simulators for I think $40?
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Old Oct 13, 2010 | 12:09 PM
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This thread says GM warranties the cats for 10years/120k miles, maybe check with your dealership:
https://ls1tech.com/forums/generatio...converter.html
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Old Oct 13, 2010 | 12:37 PM
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Originally Posted by massls1guy
This thread says GM warranties the cats for 10years/120k miles, maybe check with your dealership:
https://ls1tech.com/forums/generatio...converter.html
Thanks, I will check into that.
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Old Oct 13, 2010 | 01:43 PM
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For $240 you can buy brand new Mufflex tubes that
are a straight bolt-in, and keep your intact cats for
just-in-case. Or an annual drive to the inspection
station.

For the price of a long drill bit, a mini prybar and an
hour, you can bust out the bricks. The gutted shell
will be a bit "boomy" around 2KRPM but no rasp if you
dress some of the sharps you will find at the inlet
with a ball stone / burr and die grinder (or drill). This
will stand up to casual undercar inspection though
a smart trooper with infrared could notice its non-
functionality (It musta got old and blown out, yer
Honor!).

Check your local car club scene for someone who'll
kill the codes for beer.

Decel popping depends on tune more than pipe.
If you went for some kind of obnoxious exhaust like
a Loudmouth, yeah, catless will add to the obnoxious.
One with a real muffler, not so much.
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Old Oct 13, 2010 | 03:06 PM
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Now sounds like a great time to upgrade to longtube headers and a ORY. I wouldn't pay someone $240 to just remove the cats.
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Old Oct 13, 2010 | 04:36 PM
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Originally Posted by matt224
Now sounds like a great time to upgrade to longtube headers and a ORY. I wouldn't pay someone $240 to just remove the cats.
How much would that cost? I really know nothing about the exhaust systems. Additionally, the state I live does not require annual inspections.
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Old Oct 13, 2010 | 07:19 PM
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got my pacesetter cc lts and ory for about 520.
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Old Oct 13, 2010 | 08:39 PM
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Is there platinum in these cats? Just curious.
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Old Oct 13, 2010 | 08:49 PM
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why mess with it go LT headers or leave it alone.
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Old Oct 13, 2010 | 08:53 PM
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Default yes on platinum

Yes there is platinum, palladium, and cerium in our converters. What was that in reference to? As long as there not falling apart they are worth 25 to 35 a piece at a scrap recycling plant.
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Old Oct 13, 2010 | 09:07 PM
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For about the same price, you can get a clean bolt on install here:

http://www.summitracing.com/parts/WLK-88028/

OR save for some LTs and new ORY and a Frost mail tune, will be worth it in the long run.
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Old Oct 13, 2010 | 09:59 PM
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I hollowed out a pair of cats before, didn't notice any difference.
Then I cut the flanges off the cats, measured the angle of the bends to go from stock manifolds to an edelbrock ORY. Two pieces of bent 3" pipe cost $20, I welded the flanges on.

With a stock muffler it had a very noticable increase in off idle torque but sounded like ****.

Went with pacesetter headers, sounds better, the low end torque was less.
Later I did the rest of the exhaust.

Last edited by Jays_SSZ28; Jan 30, 2018 at 08:02 PM.
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Old Oct 14, 2010 | 10:44 AM
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Originally Posted by jtsta02
got my pacesetter cc lts and ory for about 520.
How loud is it? My WS6 is still my daily driver...I don't want something obnoxiously loud.
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Old Oct 14, 2010 | 03:30 PM
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On my old ws6 i just hallowed out the cats and on my new one i cut them out, on both cars i get a loud popping when i slow down. It seems to do it more with on the hallowed out cats.
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Old Oct 14, 2010 | 05:17 PM
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Originally Posted by mrobvious34
On my old ws6 i just hallowed out the cats and on my new one i cut them out, on both cars i get a loud popping when i slow down. It seems to do it more with on the hallowed out cats.
That is exactly what I was wondering. I won't be cutting them out then! I guess I'll save my money to try some of the suggestions listed above.
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Old Jan 3, 2011 | 02:13 PM
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Check out Texas Speed the have very good prices on these things.
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Old Jan 3, 2011 | 02:57 PM
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Originally Posted by tdevil55
For about the same price, you can get a clean bolt on install here:

http://www.summitracing.com/parts/WLK-88028/

OR save for some LTs and new ORY and a Frost mail tune, will be worth it in the long run.
Get it from a sponsor for the same price.
http://www.ws6project.com/user_stor/...oducts_id=2460

or another option:
http://www.ws6project.com/user_stor/...oducts_id=1099
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