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DPG belly skid + big round catalytic convertor

W

winkosmosis

NAXJA Forum User
Location
Maui, Hawaii
According to Dirk at DPG Offroad, most round cats fit fine with the belly skid, but a few need the cat relocated by a muffler shop. I have the bad luck of a non fitting cat.



sidemeasure.jpg


But the big problem is that there seems to be no way to move it enough. The segment of pipe between the cat and the muffler contains the O2 sensor, so only about 2" can be cut to move the cat rearward. The muffler can't really be moved back because it will conflict with the pinion.
o2sensor.jpg



How about cutting the skid and bending the pieces downward to clear the cat and also provide some protection? Is that doable with the 3/16 steel? My dad thinks bending will be possible by cutting a groove into the steel but I'm skeptical.
cutDPGskid.jpg


Could also replace the cat with a flatter one
 
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POLAR_JEEP_04 said:
http://www.jegs.com/i/Magnaflow/642/94306/10002/-1

87 at jegs... i would think a muffler shop would charge around 75 to put it on if they would even install it. some shops wont install parts unless its their part so they can mark up the price
Click to expand...

Thanks. That one is stainless steel for less money.

Edit: But that one doesn't have the O2 sensor hole I think... not "direct fit". I realized that the cat bolts on with U clamps, so I could install one myself if it's made for the XJ... Right? Do you just undo the U bolts and pull it apart?

Any direct fit stainless?
 
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You will probably have to cut the cat off. I've never had any luck unbolting an old exhaust. You can buy a bung and weld it on for your O2 sensor.
 
smccollamjr said:
You will probably have to cut the cat off. I've never had any luck unbolting an old exhaust. You can buy a bung and weld it on for your O2 sensor.
Click to expand...
Wrong!
We cut a notch around my big round cat. Used a plasma cutter. It was a free way to make it fit, but I would try t buy a flat one to fit. If you know someone with a welder, you can weld it in place of the old one yourself and not pay a shop.
 
Didn't think it was that hard to remove a cat. What if you heat the outer pipes with a butane torch? I really don't like the thought of hammering and twisting the cat and putting all that stress on all those old seals and bolts. Seems like it could create leaks.

I have a feeling this could add up to some big costs... The price of the flat cat + labor cutting out the old one + welding new pipes for the new one. I might as well buy a whole new exhaust :p. Maybe the best thing is to cut the skid. I hate to mess up such a nice piece of hardware though.

I found a stainless steel cat though http://www.autopartswarehouse.com/sku/Jeep/Cherokee/Catco/Catalytic_Converter/19962000/CAT9327.html?tlc=Engine+%26+Drivetrain
 
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call around some muffler shops for a quote on a flat cat. They will get their markup in either the part or labor. Someone probably has something in stock, I would think for $200, you could have it in/out of a shop tommorow with a new flat cat, and you'll be back to installing your skid in the evening.
 
Looks like you're in the same position I was. Although since you're in Texas you may be able to work around it. I had my muffler shop look up aftermarket replacement cats and they told me that there's aftermarket options listed for the XJ through '98, but '99 and newer they could only install an OEM cat. I don't know if Texas follows the same guidelines or not, but that was the CA rule.

When I installed my DPG skid, I was working around having the 242 TC as well as the oversize cat. I figured out a workaround by modifying my tranny mount. Here's the thread detailing what I did to gain about 1/2" of clearance.

http://www.naxja.org/forum/showthread.php?t=971301

With that said, the cat is still closer to the skid than I would like it to be. After one particular day of wheeling, it started rattling against the skid whenever I started up the engine. I temporarily fixed that with a BFH by knocking it back up where it was supposed to be. I have a final fix in the works though. I'm about to get my exhaust rebuilt (using the OEM cat) and when they lay it out I'm going to have them shorten the hanger coming off the tranny mount about 1/2" Even with it raised like it is now, I still have over an inch between it and the floor pan. Shortening the hanger should give me about 3/4" clearance between the cat and floorpan while providing me 1/2" - 3/4" of clearance between the cat and the skid plate. New engine mounts should hopefully alleviate the possibility of rattling on start up.

Moral of the story, I'd hate to cut up a perfectly good skid if it there was any way to avoid it. Hope this gives you some ideas.
 
Remember, it's illegal to remove and replace a functioning cat! Ha!

In all seriousness I'd look for otherways to fix this problem.

The best soultion would just be to relocate your cat and/or muffler to fit the skid.

The second best solution would be to modify the skid in a way that would allow the cat to fit without removing any structural integrity. Find out if it would affect any warranty present with the skid plate though.

The third best solution would be to replace the cat with a different flat style cat. And I don't really consider it a "best" solution either, seems like a waste of money to me!

If you were down this way I'd say come down here, I've got a flux welder and we could figure out something. Looks like the joint between the cat and muffler is leaking anyways!
 
fyrfytr1717 said:
I have a final fix in the works though. I'm about to get my exhaust rebuilt (using the OEM cat) and when they lay it out I'm going to have them shorten the hanger coming off the tranny mount about 1/2" Even with it raised like it is now, I still have over an inch between it and the floor pan. Shortening the hanger should give me about 3/4" clearance between the cat and floorpan while providing me 1/2" - 3/4" of clearance between the cat and the skid plate.
Click to expand...
You have to watch for other stuff when you do this. My cat is right next to the floor and it now has a puncture wound from a seat bolt.
 
fyrfytr1717 said:
Looks like you're in the same position I was. Although since you're in Texas you may be able to work around it. I had my muffler shop look up aftermarket replacement cats and they told me that there's aftermarket options listed for the XJ through '98, but '99 and newer they could only install an OEM cat. I don't know if Texas follows the same guidelines or not, but that was the CA rule.

When I installed my DPG skid, I was working around having the 242 TC as well as the oversize cat. I figured out a workaround by modifying my tranny mount. Here's the thread detailing what I did to gain about 1/2" of clearance.

http://www.naxja.org/forum/showthread.php?t=971301

With that said, the cat is still closer to the skid than I would like it to be. After one particular day of wheeling, it started rattling against the skid whenever I started up the engine. I temporarily fixed that with a BFH by knocking it back up where it was supposed to be. I have a final fix in the works though. I'm about to get my exhaust rebuilt (using the OEM cat) and when they lay it out I'm going to have them shorten the hanger coming off the tranny mount about 1/2" Even with it raised like it is now, I still have over an inch between it and the floor pan. Shortening the hanger should give me about 3/4" clearance between the cat and floorpan while providing me 1/2" - 3/4" of clearance between the cat and the skid plate. New engine mounts should hopefully alleviate the possibility of rattling on start up.

Moral of the story, I'd hate to cut up a perfectly good skid if it there was any way to avoid it. Hope this gives you some ideas.
Click to expand...

Does that mean if I replace my cat I won't be able to get it registered in California if I ever happened to move there??
 
Blaine B. said:
Remember, it's illegal to remove and replace a functioning cat! Ha!

In all seriousness I'd look for otherways to fix this problem.

The best soultion would just be to relocate your cat and/or muffler to fit the skid.
Click to expand...
I can't see any way to relocate them. They can't move backward 3" because t here isn't enough free straight pipe.

If they could be moved I'd have an unprotected cat hanging down-- but on the other hand I'd like to get a sheet of 1/8" steel bent into a long skid for the cat and muffler anyway, and bolt that to the DPG and to the framerail.

The second best solution would be to modify the skid in a way that would allow the cat to fit without removing any structural integrity. Find out if it would affect any warranty present with the skid plate though.
Click to expand...
I'm sure cutting and bending a big piece would void the warranty. I'm sure it would be strong enough still, although some of the frame rigidity benefit might be lost.

The third best solution would be to replace the cat with a different flat style cat. And I don't really consider it a "best" solution either, seems like a waste of money to me!
Click to expand...
If I could do it for about $100 it would be worth not spending a day cutting the skid... But for $200 or $300 that's getting ridiculous.

If you were down this way I'd say come down here, I've got a flux welder and we could figure out something. Looks like the joint between the cat and muffler is leaking anyways!
Click to expand...
Do you think it's leaking because of the greyish residue? I replaced the U clamps because the old ones were rusted out, so maybe that fixed the leaking
 
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