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Dual Exhaust + Cat

Posted: Tue May 15, 2018 5:53 pm
by nimslerpon
I am in the process of installing all the wonderful EPA components on my ‘79 J10 and as I started poking through the manual, I realized the Catalytic converter in the diagram is set up for a single-pipe exhaust. I have 2 separate pipes coming off the manifold and they don’t converge at any point, so I am now trying to figure out what to do. For the purpose of passing the physical inspection, I might get away with just tacking the cat on to 1 of the pipes and calling it good, but I wanted to see if anyone else here has some better insight on this.Image

Re: Dual Exhaust + Cat

Posted: Tue May 15, 2018 9:11 pm
by Stuka
Typically to pass emissions you need a cat on both exhausts if you are running dual exhaust.

Re: Dual Exhaust + Cat

Posted: Sat May 26, 2018 2:04 pm
by nimslerpon
True. Well I’ll talk to a local muffler/emissions shop and see if they have any solutions.

Re: Dual Exhaust + Cat

Posted: Sat May 26, 2018 6:51 pm
by Stuka
Any custom shop should be able to do what you want. Its nothing unusual or difficult.

Re: Dual Exhaust + Cat

Posted: Mon May 28, 2018 6:40 pm
by nimslerpon
Stuka wrote:Any custom shop should be able to do what you want. Its nothing unusual or difficult.
Awesome. Thanks!

Re: Dual Exhaust + Cat

Posted: Thu Jun 28, 2018 2:54 pm
by 81waggy
check your state's requirements. Here in NC, anything older than 99 (I think) is exempt from emissions because of the lack of OBD plug, and over 35 years exempt from safety inspection.

Re: Dual Exhaust + Cat

Posted: Thu Jun 28, 2018 7:09 pm
by gopher_6_9
Depends on how strict they are. Federal law says if it came with one cat, one cat must be maintained. As a muffler shop I cannot add a second cat and run true duals. If it has already been run that way I can however replace both cats and am not required to convert it back to a single cat..... Not sure how that will work with a state Inspection, my assumption would be if it has cats on it they'll pass it but.....