Dual Exhaust + Cat

Modified FSJ Tech Area
nimslerpon
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Joined: Sat Oct 28, 2017 1:58 pm

Dual Exhaust + Cat

Postby nimslerpon » Tue May 15, 2018 5:53 pm

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

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Stuka
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Re: Dual Exhaust + Cat

Postby Stuka » Tue May 15, 2018 9:11 pm

Typically to pass emissions you need a cat on both exhausts if you are running dual exhaust.
1981 J10 AMC 258 with HEI and Weber 32/36 DGEV Carb, T176, NP208, D44/M23 with 4.56 gears and Detroit Locker, 6" lift, 33x12.50 Cooper STT's, BJ's Offroad Rear Dozer Bumper.
2017 JKU Rubicon Lifted
Pevious Jeeps: 1975 Cherokee, 2008 JK, 2005 KJ, 1989 XJ

nimslerpon
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Re: Dual Exhaust + Cat

Postby nimslerpon » Sat May 26, 2018 2:04 pm

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

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Stuka
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Re: Dual Exhaust + Cat

Postby Stuka » Sat May 26, 2018 6:51 pm

Any custom shop should be able to do what you want. Its nothing unusual or difficult.
1981 J10 AMC 258 with HEI and Weber 32/36 DGEV Carb, T176, NP208, D44/M23 with 4.56 gears and Detroit Locker, 6" lift, 33x12.50 Cooper STT's, BJ's Offroad Rear Dozer Bumper.
2017 JKU Rubicon Lifted
Pevious Jeeps: 1975 Cherokee, 2008 JK, 2005 KJ, 1989 XJ

nimslerpon
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Joined: Sat Oct 28, 2017 1:58 pm

Re: Dual Exhaust + Cat

Postby nimslerpon » Mon May 28, 2018 6:40 pm

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

Awesome. Thanks!

81waggy
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Re: Dual Exhaust + Cat

Postby 81waggy » Thu Jun 28, 2018 2:54 pm

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...More Power!

gopher_6_9
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Re: Dual Exhaust + Cat

Postby gopher_6_9 » Thu Jun 28, 2018 7:09 pm

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.....


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