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Removing the rear 2 stock cats from stock h pipe?

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Old 12-26-2011, 02:45 AM
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Andy13186
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Default Removing the rear 2 stock cats from stock h pipe?

I was looking at these pics of a stock 04 gt h pipe. I have an 03 gt.





And it doesnt look like there are any 02 sensors behind the 2nd set of cats..


So would it be possible to remove the rear 2 cats, the big ones on the left (unless im looking at this pic backwards) and weld in pipe with no issues with check engine light etc?

anyone do this?
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Old 12-26-2011, 09:28 AM
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mineralpony
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I tried doing this last summer. My friend had the stock h pipe off of a 2003 GT. He cut the rear cats out and we tried to put it on my car (04 GT). It wouldn't line up. I'm not sure why but it wouldn't.

MAKE SURE YOU WELD THE NEW PIPING IN WHEN THE FRONT HALF OF THE H PIPE IS ON THE CAR TO AVOID ALIGNMENT ISSUES. I ran into so many of them....
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Old 12-26-2011, 12:01 PM
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02WhiteGTVert
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The first thing I did when I purchased my '02 GT in 2006 was have the 2 rear cats removed. A muffler shop in Tennessee did it. Appearantly, it's ok to remove "extra" cats..just not all of them...but anyway, no CEL came on. I later bought an O/R H and did MIL eliminators. Like mineral pony said, it needs to be done with the midpipe on the car to prevent alignment issues.
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Old 12-26-2011, 12:33 PM
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Andy13186
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Originally Posted by 02WhiteGTVert
The first thing I did when I purchased my '02 GT in 2006 was have the 2 rear cats removed. A muffler shop in Tennessee did it. Appearantly, it's ok to remove "extra" cats..just not all of them...but anyway, no CEL came on. I later bought an O/R H and did MIL eliminators. Like mineral pony said, it needs to be done with the midpipe on the car to prevent alignment issues.
Why did you decide to go for a offroad pipe? I would suspect the stock pipe with rear 2 cats removed would increase sound a bit, and possibly a bit of power. Did you notice any change in exhaust smell when removing the rear 2 cats, or switching to offroad?

thanks for the replies
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Old 12-26-2011, 12:37 PM
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02WhiteGTVert
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Originally Posted by Andy13186
Why did you decide to go for a offroad pipe? I would suspect the stock pipe with rear 2 cats removed would increase sound a bit, and possibly a bit of power. Did you notice any change in exhaust smell when removing the rear 2 cats, or switching to offroad?

thanks for the replies

the O/R H-Pipe was $40 with Mils when my friend set his GT back to stock and sold it..seemed like a legitimate reason lol.

It was a little louder and no I didn't notice the exhaust smell, not even after switching to the O/R.
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Old 12-26-2011, 01:29 PM
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WannaBeGearHead
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My buddy had his rear two cats taken off on his 01 GT just like you're asking. No check engine lights and it's been a few months now. You'll be fine.
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Old 12-26-2011, 09:21 PM
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kast1376
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Why not just purchase a used OR or catted x/h pipe? They usually go VERY cheap around here, a 100 bucks or so.
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Old 12-26-2011, 10:00 PM
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Andy13186
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Originally Posted by kast1376
Why not just purchase a used OR or catted x/h pipe? They usually go VERY cheap around here, a 100 bucks or so.
I want to make sure the check engine light doesnt come on

I play to take it to a muffler shop and having them cut the cats out and weld in the pipe, hopefully its inexpensive

Last edited by Andy13186; 12-26-2011 at 10:03 PM.
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Old 12-26-2011, 10:19 PM
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WannaBeGearHead
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Offer to let him keep the cats if he gives you a cheaper price.
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Old 12-26-2011, 10:34 PM
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kast1376
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Originally Posted by Andy13186
I want to make sure the check engine light doesnt come on

I play to take it to a muffler shop and having them cut the cats out and weld in the pipe, hopefully its inexpensive
My catted X doesn't trip my CEL light at all FWIW. MILS can be made cheap too. I *think* there is a sticky on how to do it.

Just food for thought of course. In the end its up to you
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