Single Catalytic Converter Replacement

Ok, so I've looked at a few threads and elsewhere online, but can't find anything specific to my potential project. I have a 2008 JK and the cats have gone bad. I've replaced the O2 sensors on both the upstream and downstream and its still throwing codes. Instead of buying a new pipe with the converters on it, would it be possible to replace the pipes and install a single catalytic converter? My theory is that if I get a catalytic converter that matches with the 3.8L engine and relocate the O2 downstream sensors after the cat on the single pipe, it should work. Would this be a valid option or a waste?

wickedrebel90 said:

Ok, so I've looked at a few threads and elsewhere online, but can't find anything specific to my potential project. I have a 2008 JK and the cats have gone bad. I've replaced the O2 sensors on both the upstream and downstream and its still throwing codes. Instead of buying a new pipe with the converters on it, would it be possible to replace the pipes and install a single catalytic converter? My theory is that if I get a catalytic converter that matches with the 3.8L engine and relocate the O2 downstream sensors after the cat on the single pipe, it should work. Would this be a valid option or a waste?

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Nope it will not work. The system has two o2's so you would need both of them for the computers sake otherwise you will still throw a code. You can buy weld in cats and just put them in the oem spots. Just make sure they have a hole for the second o2 either in the cat, like oem, or slightly after the cat

wickedrebel90 said:

Ok, so I've looked at a few threads and elsewhere online, but can't find anything specific to my potential project. I have a 2008 JK and the cats have gone bad. I've replaced the O2 sensors on both the upstream and downstream and its still throwing codes. Instead of buying a new pipe with the converters on it, would it be possible to replace the pipes and install a single catalytic converter? My theory is that if I get a catalytic converter that matches with the 3.8L engine and relocate the O2 downstream sensors after the cat on the single pipe, it should work. Would this be a valid option or a waste?

Click to expand...

Assuming you're thinking to put an aftermarket cat farther down in the exhaust stream, it could work, but you'd have to extend your O2 wiring for the 4 sensors. My biggest concern would be if you use a "high flow" cat, you may end up throwing a code anyway.

My prior car had a 3" aftermarket turbo-back exhaust with a 3" high flow cat and it caused the sensors to think the car was running rich. I had a to use a spacer to back out the O2 sensor to avoid the code and then pull it prior to an inspection since a spacer isn't legal. Just something to be aware of.

(The closer the cat or cats are to the manifold, the quicker they warm up. You'd also want to make sure your cat is up to operating temp prior to an inspection if you're moving it farther away from the manifolds. Better chance to pass inspection that way.)