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-   -   Removing upper catalytic converters (https://www.jk-forum.com/forums/modified-jk-tech-2/removing-upper-catalytic-converters-161972/)

HecJeep 02-01-2011 10:24 AM

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? :thinking:

Culprit 02-01-2011 12:25 PM

Its illegal!

duci05 02-01-2011 12:40 PM


Originally Posted by Culprit
Its illegal!

If you get caught.

thrshr01 02-01-2011 12:47 PM

you will more than likely cause a CEL To be set off.

HecJeep 02-01-2011 12:54 PM


Originally Posted by karls10jk (Post 2070609)
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!

monzter 02-01-2011 12:55 PM

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. :yup:

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

thrshr01 02-01-2011 01:53 PM


Originally Posted by HecJeep (Post 2070685)
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.


Originally Posted by monzter (Post 2070686)
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. :yup:

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.

HecJeep 02-01-2011 03:58 PM


Originally Posted by thrshr01 (Post 2070820)
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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