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Question for anyone who has replaced their pre-cats (00-01 Cherokees only!)

P

PumpinIron

NAXJA Forum User
Location
Portland, OR
I have a 2001 Cherokee and I recently purchased a set of Banks Torque Tube headers. In the process of installing them I plan on replacing all 4 oxygen sensors on the car as well as replacing the pre-cats in the stock down pipe. I don't have any error codes but the car has 131k on the stock cats so I figure that they're due to be changed anyways. Besides that, I just replaced the entire exhaust system with an aftermarket one so the rest of the exhaust system ought to be updated as well.

I had planned on purchasing the Walker pre-cats / down pipe that is sold on Amazon and at most auto part stores here...

http://www.amazon.com/Walker-52304-Certified-Catalytic-Converter/dp/B000VKYCQM

However, upon reading more about that part it seems that it's a genuine piece of crap. The welds are horrible, the O2 sensor holes are not aligned correctly, etc. (just read the review on that page and you'll see).

Anyways, it looks like my options are limited so I'm curious to see what other people who own a 2000-2001 Cherokee have done to replace the pre-cats.

To top this all off, I'm confused as to why the 00-01 Cherokees even had these pre-cats to begin with. I mean I've already got a cat downstream before the muffler so why on earth do I need the ones in the down pipe?

I really wish I could just get rid of the cats in the down pipe and keep the one before the muffler...

BTW: I am placing this in the modified section because I'm hoping that some guys on here might have found some sort of 'performance' replacement part or something along those lines.
 
I Can Tell You Not To Trust Most Exhaust Shops. The One I Went To Wanted $2200 And Swore Mine Was Cracked In A Few Places.

I Took It Home To Find Lose Flange Bolt. Tightened It Up And No Leaks.
 
I won't trust an exhaust shop to do it. You can buy replacement pre-cats for around $220 all day long. The issue is that I am trying to find one that someone here has experience with and can verify fitment and quality.

I would like to just get rid of the pre-cats altogether but if I did that I am sure it would throw a CEL.
 
You would need pipes with O2 bungs in them. But, removing the pre-cats is not really an issue. Other than the law stating you are not supposed to. So, in theory, you could buy an aftermarket header/manifold for a 99-down. And weld in bungs.
 
Johnnie Walker said:
You would need pipes with O2 bungs in them. But, removing the pre-cats is not really an issue. Other than the law stating you are not supposed to. So, in theory, you could buy an aftermarket header/manifold for a 99-down. And weld in bungs.
Click to expand...

That is exactly what I was thinking. However, don't you think that removing the pre cats would cause a CEL even if I had the bungs welded in with the downstream O2 sensors in place?
 
Root Moose said:
A thread you may find interesting.

http://www.naxja.org/forum/showthread.php?t=1109544&highlight=observations

As to removing the pre-cats... you'd have to replace the downstreams with O2 sensor simulators. Really, for the PITA factor at the price point of the APN down pipe, just run the cats and call it done.
Click to expand...

I think you're right. It's not worth the hassle... I ordered 4 new O2 sensors so now I just need to order new pre-cats.

The Walker ones are $220 but apparently they fit horribly and are extremely crappy quality. That being said, it appears you had good luck with the Catco 1031 fitting good? I read that the quality wasn't the greatest but I'm not dishing out $650 for those Magnaflows because that is just insane (I could drake a set for cheaper than that).
 
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Quality was fine for a part that is being installed on a normal daily driver Jeep. I'll do it again on my 2000 when the time comes.
 
Gotcha. I'm just going to order one then in that case. I don't see any 'performance' options out there for this setup (minus the Magnaflow pre-cats which even then aren't really 'performance', just nice quality) so I'll just take what I can get and be happy that I'm not paying $1000 plus for cats like the dealer would likely charge.
 
My 2001 XJ has Banks Torque Tube headers. They fit fine with the stock mini-cats.
Why do you want to replace the mini-cats? Mine has about the same amount of miles and passes the bi-annual smog test without problems.
Just install the header and be done with it, unless you know they the mini-cats are bad.

Now for the bad news, the Banks Torque Tube header is just about impossible to install, with the engine installed.
You cannot get to a couple of the lower manifold bolts. Lifting the engine and removing the driver's side motor mount and bracket will give you more room to maneuver. It's will still be very tight.

I installed mine when the head was off, allowing both the intake and exhaust manifolds to be bolted up, along with the mini-cats, before installing the head on the engine.
For all the work it was, the Banks header didn't add much, due to the tiny, restrictive exhaust ports on the 0331 head.
I wouldn't bother installing one unless the engine or head was removed.

Now the cool thing about the Banks header is it looks like it will cover the exhaust ports on the 7120 and 0630 heads.
 
Just recently replaced my entire exhaust with 2.5 SS No Restrictions

Mine is a 1998 XJ Sport,
Granted its not 00'-01', I don't see the difference.

Still working to post a build thread... however here are some spoilers.

Started with a Doug Thorley Exhaust Manifold



Welded the rest





 
I'm not sure why you would want to replace the pre cats. Take them down and shine I light through them. Cats don't go bad unless there is bad stuff coming out of the motor. Fuel, oil, etc etc
 
You can install the Banks torque tube header with the engine in the engine bay. I went through this last month.

It's a bitch, but almost all of the bolts can be accessed from the side of the engine with a combination of sockets and extensions. There is one bolt at the front of the the rear bank on the bottom that can be reached from underneath the engine using a normal wrench by sliding your arm directly vertical to the bolt.

Thankfully the bolts don't require large torque for installing.
 
I am only replacing the pre cats because they are so cheap that I might as well. Not to mention mine are so rusted that they are probably going to rust through at any point now. Plus, I may not have a CEL but no catalytic convertor is probably performing optimally with 131k miles on it I suspect.

My Banks torque tubes have been ceramic coated so while I do not expect to see any power gains from them I do expect to see slightly reduced intake temps which will be good for the supercharger!

I can clearly see that installing them will be a bitch. I am almost contemplating just paying someone else to do it because I simply don't feel like wrestling with those hard to reach bolts.
 
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