Catalytic convertor replacement on 07 3.8

Danarch

Danarch

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My son has 07, 3.8L and finally ordered replacement cat’s. The parts go from the exhaust manifold to the about mid point back. From what I can tell the system simply bolts up to the exhaust manifold. On other vehicles they have had some sort of “gasket ring” where the exhaust mounts to the exhaust manifold. I am not sure the exact name of the part. Does anyone know on the Jeep does the new exhaust simply bolt up to the exhaust manifold without anything at the connection? Just would like to have all the parts prior to getting it. He has ordered all new O2 sensors. Thank you for any input.
 
Thinking it’s the “donut” gasket that u are speaking of. Don’t think our 07’s have them from what I’ve been told🍺🍺
 
BigAL07 said:
Thinking it’s the “donut” gasket that u are speaking of. Don’t think our 07’s have them from what I’ve been told🍺🍺
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Thank you for the info, that is a good description as it sort of does look like a donut, just a lager hole 😂.
 
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Danarch said:
Thank you for the info, that is a good description as it sort of does look like a donut, just a lager hole 😂.
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Had mine done in the Fall . The kit comes with the mini donuts . I have to do mine again as the unit I got the cross pipe hung to low to put on trans skid plate .
Found a place up here that specializes in exhaust systems and gautentee perfect fit . It’s next on the list to get done .
May I ask where you purchased cats?
 
Speartip said:
Had mine done in the Fall . The kit comes with the mini donuts . I have to do mine again as the unit I got the cross pipe hung to low to put on trans skid plate .
Found a place up here that specializes in exhaust systems and gautentee perfect fit . It’s next on the list to get done .
May I ask where you purchased cats?
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He ordered them from RockAuto.com. I did’t see any donuts in the kit, just the cat’s and pipe and a couple of clamps.
 
So in case anyone else sees and and has the same question, I decided to go look up the part my son ordered and per their information an inlet gasket is not required. I am not sure if it varies by mfr or not.

IMG_1182.jpeg
 
Danarch said:
So in case anyone else sees and and has the same question, I decided to go look up the part my son ordered and per their information an inlet gasket is not required. I am not sure if it varies by mfr or not.

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So are those Cats the same as OEM if not he could get downstream O2 CEL's and have to get O2 foolers like I did.
 
@BLACKJKU well they better be! Cost the poor kid $2,600 for CA CARB compliant cat’s. They said OEM replacement, have the EO number stamped / engraved on them. He also bought all four new o2 sensors to install. He took time off Labor Day weekend, so we will install them then. Actually looks pretty simple, assuming the bolts come out. I need to go out and look at what type of bolts hold the exhaust to the manifold as figure best to just install new ones and have them on hand. I hate getting into a project to only realize I have to run somewhere to get parts or a tool.
 
BLACKJKU said:
He could have bought long tube headers and high flow cats for that price.
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Bear in mind that long tube headers are not street legal anywhere in the US. It is illegal to change the number or locations of the cats. Yes, it's a stupid law, but it's something to keep in mind.
 
Dirty Dog said:
Bear in mind that long tube headers are not street legal anywhere in the US. It is illegal to change the number or locations of the cats. Yes, it's a stupid law, but it's something to keep in mind.
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Never heard of that law in Indiana, but we don't have inspections either.
 
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I am sure he could have, but in CA we have special rules and replacement cat’s have to be CARB certified (not sure exactly what the difference is, other then cost) and they have to have the executive order (EO) engraved on the cat’s. By law the inspection place is supposed to check and if the EO is not engraved or is different then what is in the system they won’t pass. The EO number is in the image below. It is crazy!
IMG_5866.png
 
Dirty Dog said:
It's Federal. Indiana is still part of the US...
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How many cats does the 3.8 engine use, I have 2 cats? My Jeep had shorty headers on it when I bought it and a hacked up dual exhaust so what I put on was a great improvement.
 
Danarch said:
I am sure he could have, but in CA we have special rules and replacement cat’s have to be CARB certified (not sure exactly what the difference is, other then cost) and they have to have the executive order (EO) engraved on the cat’s. By law the inspection place is supposed to check and if the EO is not engraved or is different then what is in the system they won’t pass. The EO number is in the image below. It is crazy!
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The California Air Resource Board (CARB) makes the rules for CA, and they can make them stricter than the federal laws, but never less strict. Most aftermarket parts manufacturers are CARB compliant, because it would be silly to voluntarily cut yourself off from such a large market.

Again, I think it's a stupid law. I used to own a '95 TA Convertible. Fun car. Had an ATI Procharged 383 stroker LT1 in it. Technically not street legal, because I had dual exhaust with two Random Tech cats. The factory only included one. It could pass the sniffer test easily. I'm a firm supporter of clean air. I'd like my grandkids to be able to breathe. But putting the sniffer in the exhaust should be the only test you have to pass. My Corvette is also technically not street legal, because I have long tube headers, which moves the cats further from the engine. It also passes the sniffer with flying colors.
 
Ahhh it’s so nice to live in TN, at times. I have never in my 40 years of driving had a car emissions checked. I actually just finished moving my mustang from 1 shop to another, no hood and lots of shiny aluminum parts showing and very loud. Seen 2 cops, they just wave and we all go on our way.
 
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There are 4 of them. Well at lease I count each as a cat, maybe the pair in each side is one.

I am not sure why the difference is between a CARB certified cat and typical cat.

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Others have said it, but I'll chime in. You do not need to use the donut. Unless your headers are worn at the connection joint, than all will be well. ReTorque the bolts within 100 miles though. I have the same kit on mine. I installed headers too. Make sure he pulls the heat shields off and inspects the manifolds as they are very prone to Crack. Suck to do all that work to have to pull it all apart to replace them. I got 180.00 for my old cats at a recycling station.

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