cat removal

[Brian Felts]

I have a 2000 Cherokee Sport 4x4.I want to add a header and remove my catalytic Converter to compliment my 40 series flowmaster. I have a 4.0 six with a k&n and homemade air intake.my engine is otherwise stock.I need to know how to fool the back o2 sensor.

[Eagle]

Three points:

1) What you are proposing is illegal under Federal law, and depending on where you live may be illegal under your state's laws.

2) IMHO we cannot advise you on this w/o becoming accessories. Anyone who does post after this is expressing his/her own opinions and is not speaking for NAXJA.

3) What is it you hope to accomplish by this? The new cats are pretty much high-flow and you won't gain much (if any) performance by removing it, so why break the law and give 4-wheelers a bad name for not caring about the environment?

[dvsjoker]

i have to agree with naxja i had removed mine looking for a problem and i cant wait to put it back many say its faster that no ttrue i have the same flowmaster and its loud to loud i think so stick with stock not cause the law persay but it just feel better

[Brian Felts]

You have enlightened me. I withdraw my question about removimg my cat.However i would appreciate info on a header for my 2000.It seems like us 2ooo up owners have been left in the cold on performance parts.

[seanR]

I agree, I have been looking for that kind of goodies and not many are availible.

[Brian Felts]

I agree with your opinion on 2wd xjs and v6 mustangs being the proud owner of a 2000 4x4 and an 85 5.0. so why did you assume my jeep was 2wd?

[Phil]

look at all his posts, that's his signature. ;)
Go up to user cp>edit profile and the stuff you enter for your signature will be in every post you make.

[Drewlee77]

There really isn't any point in putting a header on a 2000. Not only does it already have a tubular header (the new ones that don't crack), but that would require removing the two pre-cats - which for all the already-stated reasons, would be a bad thing, and is probably why there are no aftermarket headers. If you pulled off the cats (2 pre-cats, plus the cat - which is said to be the same as the V8 ZJ's - plenty of flow) and replaced the header you MIGHT gain 3-5 hp - if you were lucky. Just the header MIGHT give you as much as 3 hp, but probably less. It's not worth the money - especially since you'd have to have one custom built. It might not be the answer you were wanting - but basically, you already have a great exhaust.

Did you notice any gains with the 40 series? I haven't heard much talk on how restrictive the muffler is - but mine is just about crushed to death.... How loud is the 40 series delta in the cabin?

[Faux4X4]

Disclaimer- this is for information purposes only. I took off my cat 93 4.0 and I did notice a little more power. But when I wanted to smog it I could not get the test pipe off to put the cat back on, so I had to pay 35.00 at a muffler shop to get it put on. And for the pre-cat "problem" summit sells a plug that you stick in the O2 plug that fools it into thinking it is still there. Again I do not condone this nor does NAXJA :angel:

[Dr. Dyno]

The latest XJ's that have the redesigned exhaust manifold with expansion joints and dual outlet pipes with precats will see little if any benefit from a header. The front half of the exhaust is pretty good on these models unlike the earlier 4.0 HO models. The front pipe joining the cat is 2.5" in diameter and much better than the crushed pipe that came with the old ones. Just install a high-flow main cat and performance muffler and you're pretty much done on the exhaust side of things.

[XJ Saga]

My experience:
Headers: Jeep already installed one from the factory, I know people who have installed high dollar aftermarkets from Banks and resulted in no gains that they could even feel SOTP.

Cat conv: 00-01 XJ's use the same one for the 4.7 V8's so there is no flow issue for the I6 to even warrant an aftermarket.

Muffler: to date the ONLY restriction in the exhaust stream and a flow 40 or 50 will cure that with confirmed dyno gains.

Conclusion: Appreciate what Jeep engineers already managed to do for you. Crawl under your Jeep one time and examine your exhaust system, then go crawl under one of your buddies older XJ's and you'll see what I'm talking about.

[JnJ]

Hehe nice sig Sean.

Pround owner of a 98 Mustang Cobra. :D Oh ya and a 4wd XJ....and a 2wd MJ :( (this may change soon........)

[Brian Felts]

pre cats? is that a california thing?Mine has a cast iron split manifold dumping into a 2 into 1 cross pipethat turns 2 90s and goes into the cat.word around here is that the cat is problematic. Ive got 87k miles on my rig.what problems would i run into adapting a banks tj split header and downpipe to my xj?I have decided to keep a cat on it.:angel:

[94_2wdcherokee]

i agree

[Rob Bolin]

Don't even think about removing the cat, The 2000's are an obd II that means they measure exaust gasses before and after the cat... so removing will tell the ecu that it is running rich aand then lean out the mixture and keep leaning till you burn up the head there are Hi flow cats out there for around $120.00 ... as far as more power cut that $50.00 POS muffler off and run a straight pipe like all the other really fast jeeps, hacked mine off and wow what a differance and it only cost me $0000.000 pretty cool, and not really that loud. No one in my little group runs mufflers... Just a thought ..-

[JeepSpeed]

120 bones for a hi-flow cat? Hmmm, that sucks. Get a Carsound cat off ebay. Somewhere around 30-40 bucks, the guy who sells them is cool, and they are quality pieces. Universal fit, but I didn't have any real problems. This forum is where I learned about em, days before i wouldve bought a $100+ one. Passing on the knowledge. :D

[ReBeL XJ]

My 89 is straight piped. Me and a few friends got bored so we cut off the cheapo muffler. With it piped its loud and annoying as hell when it shifts into overdrive and the engine is warm. sounds like a damn fart pipe ricer is next to me. Im getting 2.5 in piping, catco hiflow cat and a single chamber flowmaster with dual 4in tips on her when i put the new motor in.

ya with the staight pipe i noticed more power(slightly) at acceleration but at highway speeds it almost feels like it bogs down and has less throttle response.

But hey to him his own. its your jeep not ours.:thumbdn:

[azxjman]

If anybody get more ideas to cut off there cat DO IT then send it to me because mine was removed without my consent by a boulder.

[dogtired]

Hi all

So, let me get this straight... my 2000 XJ 4.0L's only exhaust restriction is the muffler? Coolness! Was gonna replace the entire exhaust system eventually, the header, the cat as well as the muffler. Saves me a ton of moola! Thanks!

Originally posted by XJ Saga
My experience:
Headers: Jeep already installed one from the factory, I know people who have installed high dollar aftermarkets from Banks and resulted in no gains that they could even feel SOTP.

Cat conv: 00-01 XJ's use the same one for the 4.7 V8's so there is no flow issue for the I6 to even warrant an aftermarket.

Muffler: to date the ONLY restriction in the exhaust stream and a flow 40 or 50 will cure that with confirmed dyno gains.

Conclusion: Appreciate what Jeep engineers already managed to do for you. Crawl under your Jeep one time and examine your exhaust system, then go crawl under one of your buddies older XJ's and you'll see what I'm talking about.

[XJ Saga]

Originally posted by dogtired
Hi all

So, let me get this straight... my 2000 XJ 4.0L's only exhaust restriction is the muffler? Coolness! Was gonna replace the entire exhaust system eventually, the header, the cat as well as the muffler. Saves me a ton of moola! Thanks!

For the most part that is correct, the muffler I can confirm as well as the headers. One guy I know is running high 14's with his 00 XJ @ Englishtown raceway with all of the bolt on's I have with the exception of a Banks header, he stated to me that he could not even feel a seat of the pants difference after the header install. The only item I can't completely vouch for 100% is the cat, I've ordered a carsound at a good price so I'll let you know. But at most it'll yield 3-4 ponies and not much more. I know it's the same cat used on V8 ZJ's, but that does'nt mean it's not a restriction. Anywho I'll advise of my results with the carsound. As for the headers, unless you have problems with your factory version I would'nt bother until years down the road when the factory may finally need replacing. :)

[dogtired]

XJ Saga,

thanks for your input, I never heard of carsound... where ya get it and how much? As for the muffler... what company? I have used Flowmasters before when I had my 5.0L mustang, so I am familiar with them. Any other company specializes in XJ's exhaust or just stick with name brands?

[XJ Saga]

Originally posted by dogtired
XJ Saga,

thanks for your input, I never heard of carsound... where ya get it and how much? As for the muffler... what company? I have used Flowmasters before when I had my 5.0L mustang, so I am familiar with them. Any other company specializes in XJ's exhaust or just stick with name brands?

Carsound makes high flow catalytic convertors for just about every car including our XJ's. Many online and well known performance sites sell them as does Kolak on the JU forum, also you can get them on ebay too. As for the muffler Flowmaster's are very good, Gibson, Borla, and Banks are all equally on par

Regarding my previous post, I meant to say that the stock cat is the same as a V8 ZJ, it sort of sounded as if I meant the carsound cat. ;)

[hjeepxj]

Isnt carsound the guys that sell some cats on ebay for SUPER cheap?

XJ Saga, you ever ran your XJ at the track?

mmmm I love 14 second XJs :D

[XJ Saga]

Originally posted by hjeepxj
Isnt carsound the guys that sell some cats on ebay for SUPER cheap?

XJ Saga, you ever ran your XJ at the track?

mmmm I love 14 second XJs :D

Yep, I do believe carsound had the big sale going on ebay for $40. No tracktime yet, just 0-60 runs and 60ft times. Consistent mid to hi sixes 0-60, and 2.1 60ft, I'm pacing myself ;)

[hjeepxj]

Originally posted by XJ Saga
Yep, I do believe carsound had the big sale going on ebay for $40. No tracktime yet, just 0-60 runs and 60ft times. Consistent mid to hi sixes 0-60, and 2.1 60ft, I'm pacing myself ;)

:D


Keep us posted if you go to the track :D

[AZGOLDXJ]

Don't forget the MagnaFlow Performance mufflers they are completely flow through and sound great. they have 14" and 18" for the xj. I just installed the 18" five days ago with 2.5" cat back pipeing and i'm getting deep,rich tones at idle and lower speeds and at highway speeds its almost invisible. cost was $100.00 installed. Also go to [url]www.go.jeep-xj.info/ for more info on exhaust tech. worth considering.
Good luck, AZGOLDXJ.

[June]

Alright, let me get this straight because I'm still a little unsure. I was planning on replacing my cat and muffler soon. So it's not necessary for me to replace the cat on my 2001 XJ with a highflow cat? So I can just replace the muffler w/ another highflow version and that should be enough? Is this right? Thanks for the clarification.

June

[XJ Saga]

I've confirmed for myself that a highflow cat is well worth your time/money even for 01's. I say go for it.

[hjeepxj]

You can get highflow cats off of ebay for 40ish.

http://www.stores.ebay.com/id=60497141&ssPageName=L2