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  1. #1
    Sr. Apprentice 1500ExtChevy's Avatar
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    Default Cutting the Catalytic Converter

    I'm hoping someone has some insight on Catalytic Converters for me. I am looking to cut open that Cat along the welded seam and pry it open and flush out the Cats will it turn on any OBD codes? My dad has a 2500 Duramax that he did it to but no codes for him wondering if it would be the same? Thanks.
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  2. #2

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    I did this on my truck . it will throw a o2 sensor code and your service engine light will come on . You will have to put cats back on it and drive through the drive cycle before it will pass emissions this will usually take a couple hundred miles to do . My advice would be to buy another set of cats and a y pipe to swap out for emissions . Kinda expensive but it will save you a lot of time cutting and welding new cats on every year
    [/SIGPIC]2001 gmc 1500 ex cab,3" body lift,3" leveling kit,315/75/16 hancook dynapro mt's, punched cats, custom flowmaster exhaust, k&n with custom intake,camo kit, Dual trumpet air horns,Siren, Custom camo interior LIFT IT FAT GIRLS CANT JUMP

  3. #3

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    What you can do, is take a reciprocating saw, make CLEAN cuts to cut off the cats. And then unbolt the pipe from the manifolds, and weld on flanges to each end, so that you can unbolt your cats, and take them off. And then do the same to a piece of pipe. So you can bolt and unbolt. Instead of cutting and welding. Welding is a pain in the arse if you don't unbolt the pipe from the manifolds. I know, because my exhaust has a crap load of leaks.

    I also have my cats cut off. My 02 sensors are very dirty, so my truck doesn't have the code on all the time. It just decides when it wants it on or not.
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  4. #4

    Default

    Go and look up oxygen sensor spacers. I have made them out of spark plug anti foulers, and used ready made ones. You can use them on the rear o2 sensors when you have a bad cat or no cat and avoid p0420 codes. This is the item number of one on ebay 140355455139
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  5. #5

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    they make ho2 eleminators for that. it basically has resistors inside to send a good signal back to the pcm. their pretty cheap too
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  6. #6
    Sr. Apprentice 1500ExtChevy's Avatar
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    Default

    Now what about removing the muffler on the truck? Will that increase the sound of the exhaust? Thanks again guys or gals.

  7. #7
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    Default

    removing the muffler will make it uhhhh quite loud.... I dont know what year you have.. I know that in my 02 chevy with the 5.3 i could set off car alarms in a parking lot very easly.. And on my 88 it wasnt as bad but still loud... I wouldnt do it id just put your choice of performace muffler in if you want some more sound.
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  8. #8

    Default

    Quote Originally Posted by Loggerhead Mike View Post
    they make ho2 eleminators for that. it basically has resistors inside to send a good signal back to the pcm. their pretty cheap too
    Where can I find these at?
    1998 silverado 1500 4x4 - 5.7L vortec
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  9. #9
    Sr. Apprentice dannys99's Avatar
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    Default

    Heck with cutting the cats, just take a hammer handle and beat the ceramic out of it. I just cut mine out and put a strait pipe. Your check engine light will come on because it will think the cat is not cleaning the exhaust. As far as performance I barely noticed a difference,only on the top end, but it sure sounded a lot better. I am running no cats with 30 series flowmasters and a crossover pipe, It is prety loud.
    "If I were lie'n I'd be cry'n and I aint shed a tear"

  10. #10
    Sr. Apprentice 1500ExtChevy's Avatar
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    Default

    Yeah defintaly dont want to mess with emissions had an 02 Grand Prix GT grinded down the seem of the Cat. where it was welded pryed open that Cat. and smashed up the ceramic inside and sucked it out with a wet/dry vac and welded it closed. Unfortunately about 3 months later emissions came and well had to spend a 100 for new a Cat. and go back.


    But easier said then done I will prolly just buy my buddies wireless exhaust cutout off his 07 TB SS since it sticks half open on him he's getting rid of it for half price so thats my easy way out.

    Thanks again guys for the much informative opinions and thoughts.

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