Removing upper catalytic converters

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  1. #1
    JK Enthusiast HecJeep's Avatar
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    Default Removing upper catalytic converters

    Has anyone removed the upper catalytic converters?

    Here is the problem, they are to close to the exhaust manyfolds and whether you have shorty headers or stock manifols they trap too much heat and they crack.

    I know there are some post of losing power if you remove the lower ones and also the sensors would have to be put somewere along the pipe but I have not found anything on the uppers!

    Any advise?
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  2. #2
    JK Enthusiast Culprit's Avatar
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    Its illegal!

  3. #3
    JK Enthusiast duci05's Avatar
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    Quote Originally Posted by Culprit
    Its illegal!
    If you get caught.
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  4. #4
    JK Freak thrshr01's Avatar
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    you will more than likely cause a CEL To be set off.

  5. #5
    JK Enthusiast HecJeep's Avatar
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    Quote Originally Posted by karls10jk View Post
    Removing and modifying the cats is illegal. Have you thought about wrapping the upper with exhaust wrap to keep the heat "at bay" (pun intended but totally serious all the same)
    I am awere of the legal issues specially here in California, this thing has 4 cats!!! Little over kill Chrysler!
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  6. #6
    JK Newbie
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    back in the day with my old twin turbo Z, you could remove the cats and "gut" them by breaking apart all of the insides with a drill, hammer, whatever.. basically leaving a hollow cat

    Still looked legal and worked wonders for that engine.

    Not condoning, just sharing. I'd do anything back then for a few more hp.

  7. #7
    JK Freak thrshr01's Avatar
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    Quote Originally Posted by HecJeep View Post
    I am awere of the legal issues specially here in California, this thing has 4 cats!!! Little over kill Chrysler!
    It's not overkill by Chrysler. All manufacturer's are now doing 2 cats per bank. It actually does a great job at minizing the emissions that comes out of the tail pipe. Hate to risk sounding like a tree hugger but we should add that to our "tread lightly" motto. Pollution and emisions noise goes into consideration when they start closing trails down.

    Quote Originally Posted by monzter View Post
    back in the day with my old twin turbo Z, you could remove the cats and "gut" them by breaking apart all of the insides with a drill, hammer, whatever.. basically leaving a hollow cat

    Still looked legal and worked wonders for that engine.

    Not condoning, just sharing. I'd do anything back then for a few more hp.
    Actually "hollowing" out a cat is bad for performance. You want your outflow of exhuast to be smooth so the exhaust gasses stays hot (hot air moves faster) and have an even flow. Having that big hollow chamber will cool the air and "collect" in it causing back pressure and bad flow. Expansion chambers only work on 2 strokes.

  8. #8
    JK Enthusiast HecJeep's Avatar
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    Quote Originally Posted by thrshr01 View Post
    It's not overkill by Chrysler. All manufacturer's are now doing 2 cats per bank. It actually does a great job at minizing the emissions that comes out of the tail pipe. Hate to risk sounding like a tree hugger but we should add that to our "tread lightly" motto. Pollution and emisions noise goes into consideration when they start closing trails down.



    Actually "hollowing" out a cat is bad for performance. You want your outflow of exhuast to be smooth so the exhaust gasses stays hot (hot air moves faster) and have an even flow. Having that big hollow chamber will cool the air and "collect" in it causing back pressure and bad flow. Expansion chambers only work on 2 strokes.


    Thanks that makes alot of sence, maybe I'll just put the stock one back on and just be happy with that.
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