Dual Exhaust + Cat

Modified FSJ Tech Area
Post Reply

Topic author
nimslerpon
Posts: 22
Joined: Sat Oct 28, 2017 1:58 pm

Dual Exhaust + Cat

Post 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
User avatar

Stuka
Site Admin
Posts: 11789
Joined: Thu May 12, 2011 5:53 pm
Location: CA
Contact:

Re: Dual Exhaust + Cat

Post by Stuka »

Typically to pass emissions you need a cat on both exhausts if you are running dual exhaust.
2017 JKU Rubicon
Pevious Jeeps: 1981 J10, 1975 Cherokee, 2008 JK, 2005 KJ, 1989 XJ

Topic author
nimslerpon
Posts: 22
Joined: Sat Oct 28, 2017 1:58 pm

Re: Dual Exhaust + Cat

Post by nimslerpon »

True. Well I’ll talk to a local muffler/emissions shop and see if they have any solutions.
User avatar

Stuka
Site Admin
Posts: 11789
Joined: Thu May 12, 2011 5:53 pm
Location: CA
Contact:

Re: Dual Exhaust + Cat

Post by Stuka »

Any custom shop should be able to do what you want. Its nothing unusual or difficult.
2017 JKU Rubicon
Pevious Jeeps: 1981 J10, 1975 Cherokee, 2008 JK, 2005 KJ, 1989 XJ

Topic author
nimslerpon
Posts: 22
Joined: Sat Oct 28, 2017 1:58 pm

Re: Dual Exhaust + Cat

Post by nimslerpon »

Stuka wrote:Any custom shop should be able to do what you want. Its nothing unusual or difficult.
Awesome. Thanks!

81waggy
Posts: 111
Joined: Wed Mar 09, 2016 7:30 am

Re: Dual Exhaust + Cat

Post 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.
81 Wagoneer with a TBI 350 Vortec.
83 Wagoneer - 360 Quadratrac
69 Wagoneer - 350 Diesel trail rig
70 Wagoneer - 1414x

gopher_6_9
Posts: 20
Joined: Wed May 29, 2013 5:48 am
Location: lawrenceburg, tn

Re: Dual Exhaust + Cat

Post 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.....
Post Reply