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nate
05-02-2005, 04:03 PM
Anyone have an idea how far away the cat needs to be from the floor, etc? I'm working with a tight area and I'd rather not burn the Jeep down or kill the cat from it overheating.

Nordic1
05-02-2005, 04:35 PM
I don't think it really matters for far the cat is from the floor... obviously you can't bolt the thing to the frame but I'm sure as long as there is a little air-flow, you'll be fine.

If you're really worried about heat, why not wrap the thing?

OverkillZJ
05-02-2005, 04:39 PM
If you're really worried about heat, why not wrap the thing?

Right. Rap the cat convertor so it gets even hotter. BRILLIANT!

JeepinHank
05-02-2005, 05:18 PM
Install it where you want, and run it. If the carpet starts to smoke - its too close.

Seriously though, I'm in the same boat as you. My thinking was to put it about an inch or so away from the floor pan, and about the same distance from the frame rail. VonZipper might be able to offer a little insight since he's been running his for a while now. Hopefully he will see this and offer up his experiences.

My plan was to run the cat in front of the front x-member, and then run a short piece of tubing through the belly skid area, and then to the muffler behind that. I've also considered tucking the cat up in the belly skid area, but I would think you'd need to come up with some sort of heat shield to to keep the t-case from getting too hot. Either way heat is going to be an issue.

Jim311
05-02-2005, 09:08 PM
Mine had a heat shield over it.... I suggest you do the same regardless of where you put it.

trailzj
05-02-2005, 11:47 PM
I smashed my cat into the floor on a obstacle, pryed it back about a fingers thickness away from the heat sheild. Its been around 6 months and I've had no problems.

Al

Nordic1
05-03-2005, 01:29 AM
If you're really worried about heat, why not wrap the thing?

Right. Rap the cat convertor so it gets even hotter. BRILLIANT!

Yea the internals get hotter but who cares... I cooked the crap out of mine and it still works. With wrap I am able to hold onto the cat with bare hands (mind you not for long but its a great improvement over stock).

nate
05-03-2005, 02:27 AM
Chase, because if you overheat the cat, you burn it out and it will plug up.

Hank, yeah I am thinking to run it kinda between the two crossmembers. Otherwise, it's gotta go right by the tranny. What I was trying to figure if I should put some holes in the skid to help with air flow. I'm curious how hot it really gets and if I really should worry about it. I may just run it and see.

So far I think I'll have to run a glasspack with a turn down... or a small tube muffler. It's gonna be tight for sure. I may sure bring it to the exhaust shop and have them figure something out :mrgreen:

JeepinHank
05-03-2005, 10:06 AM
How loud is a glass pack? I love the size, but I'm hesitant on making my heep any louder than it already is...

As for drilling holes in the skid to aid in airflow, I don't think I'd go that route unless it proves to be absolutely necessary. I have a feeling that you're biggest problem will be heat getting into other things on your rig, not getting out of the cat (if that makes any sense). You can maybe go the route of putting some reflective heat shield between the cat and the t-case if things seem to get too hot.

I've been thinking about using a high-temp paint on the skid just so that it doesn't cook it off when things get heated up. My plan is to take things out on a shakedown run, and check how hot everything is getting after a couple of hours.

OverkillZJ
05-03-2005, 11:56 AM
Chase, because if you overheat the cat, you burn it out and it will plug up.


I think what you meant to say was: "Chase, you're an idiot :toimonst: "

nate
05-03-2005, 02:31 PM
Yes, I did mean that, but I felt I could be respectful to a fellow board member :mrgreen:

Hank, with the glasspack, it's pretty loud. When I parked the Jeep, I just had a hollowed cat, then the glasspack and a turn down. It sounded ok, but it's not too quiet. Download the last few vidoes off my webpage and you'll be able to hear it.

JeepinHank
05-05-2005, 10:40 AM
I was talking to one of my mechanic buddies last night, while we were working on my heep. I asked him about the cat location, and he made a pretty good point. The stock cat is pretty much located in the same place (right next to the t-case), and you've still got a hot ass exhaust pipe running right next to it and the tranny no matter where you put the cat. It would be interesting to know if exhaust/tubing temps are hotter before, at, or after the cat, but I honestly have no clue.

The full belly skid shouldn't make too much of a difference considering the heat shields on both the floor pan and cat. Heat has a tendancy to travel up (I know - duh), so the biggest issue is the interior floor - which is shielded. The skid isn't going to make much of a difference over what we're experiencing right now. At highway speeds - there's plenty of air flow (that'll be the same with or without the skid), and when wheeling at a crawl - there's very little air flow either way.

Stock, there's probably an inch of space (at most) between the floor pan/heat shield and the catalytic converter - which pretty much keeps the exhaust up above the bottom of the frame rail. I'd go for about the same if you can.

Just figured I'd post back with someone else's opinion. Hope this helps.

Hank

Vonzipper
05-15-2005, 02:23 PM
Sorry guys, I missed post, There really isnt a good spot for the cat and my thought was to get the most airflow by the thing, I looked at putting it between the crossmembers and by the transmission, the transmission won, I've checked transmission temp with it in that location and no problems yet, wait till it get 100 deg here or on the Rubicon, I also thought of making it removable, it wouldnt be that hard. as far as my exhaust system , i dont run a muffler, I am running a small resonator between the crossmembers and that's it, not too loud, I know with the cat off it will be much louder so i guess it's a "work in progress"


Scott

dasVettemeister
05-16-2005, 01:51 AM
If you're really worried about heat, why not wrap the thing?

Right. Rap the cat convertor so it gets even hotter. BRILLIANT!

It's ok for parking lot use! :weedman:

Vonzipper
05-16-2005, 05:36 PM
The other thing to look out for Nate is quenching it in cold water like in Alaska, Thats the other reason I didnt want it by the crossmembers, I wanted water to move by it quick, We see alot of cat's fail just for that reason


Scott

norcaljr
05-16-2005, 06:25 PM
When I 1st went long arms, I ran a cherry bomb glass pack with a car sound cat, it was SOOOOOOO loud and sounded like shit. I ended up getting a round dynomax muffler from Kolak that worked really good.

When I went to a 4 link, that muffler was too long, so I had the shop push my cat as far forward as they could (over the crossmember) then got a small magnaflow muffler thats welded right to the cat, and then a down turn. Sounds ok, but i think im loosing a bit too much back pressure, so im thinking of re-doing with 2-1/4'' vs the 2-1/2''

OverkillZJ
05-16-2005, 06:59 PM
When I 1st went long arms, I ran a cherry bomb glass pack with a car sound cat, it was SOOOOOOO loud and sounded like shit. I ended up getting a round dynomax muffler from Kolak that worked really good.

When I went to a 4 link, that muffler was too long, so I had the shop push my cat as far forward as they could (over the crossmember) then got a small magnaflow muffler thats welded right to the cat, and then a down turn. Sounds ok, but i think im loosing a bit too much back pressure, so im thinking of re-doing with 2-1/4'' vs the 2-1/2''

I had the same experience, only I broke the cherry bomb off twice. They're very fragile at the ends.

I love the magnaflows, ran that for awhile until I had a little incident. Now I have a Moroso which I love too, mellow but throaty. but mostly, doesn't break so easly!

Just clears the 4 link.

Backpressur's fine for me, I have borla headers (2.5" lead pipe) to the 3" cat and 3" muffler then downturn. I think the diff is that the muffler isn't really a flow through like the magnaflow.

offroadjeepin
05-18-2005, 11:16 PM
Just Take the Cat OFF. Im runnin a Ravin With no cat. I love the Sound But did like it more when i had just the cat on it.

JeepinHank
05-19-2005, 09:21 AM
Just Take the Cat OFF. Im runnin a Ravin With no cat. I love the Sound But did like it more when i had just the cat on it.

My State / County just came under OBDII emissions regulations...

I drive a `96, so I fall under the regs. :axe: