Catalitic Converter Question

[bjoehandley]

I'm going to have to replace the 148k mile factory exhaust on my '98 XJ here before the last weekend in June and am thinking about doing the cat at the same time and maybe bumping up to 2.5" tubing from at least the cat back, if not maybe having it done header back. Any suggestions? The engine is stock with the exception of a cut open air box and drop in K&N filter.

 

[gradon]

Performance curve has 2.5" cats and cat-backs. Should be less than $200 shipped for it all. Make sure to get a cat with an o2 bung in it.

 

[aparke4]

go for it

i run a magnaflow cat and yes you need and 02 bung with a flowmaster and love it (I6 4.0) . I also have a custom downpipe to get rid of factory kink but since you have no lift I would just go cat back kit and new cat.

 

[bjoehandley]

I should be able to get the cat and muffler Advanced Auto a former customer works for (he gave me a deal on parts I bought last time) and theres a local chain that should be able to do the install for cheap too. I wasn't to sure about that kink on a stock height high pinion truck, probably should stay stock there then.

 

[bjoehandley]

You guys wouldn't happen to have a part number handy for the Magnaflow 2.5" OBD2 legal cat by chance?

 

[Ben824]

For what its worth I have had two cats put on my 97 XJ that didn't have O2 sensor bungs on them. Most muffler shops should carry bungs and can easily cut a hole and weld a bung on it. I haven't thrown a code yet and its been 7 years (5 years on the first one and 2 on the second).

This is the one I have now. http://www.summitracing.com/parts/MPE-54955/?rtype=10
I am pretty happy with it so far does the job and it is small and compact.

 

[gradon]

magnaflow 94236:
http://cgi.ebay.com/ebaymotors/Magn...ptZMotorsQ5fCarQ5fTruckQ5fPartsQ5fAccessories
Some take offers, so offer $60 for one.

 

[streetxj]

I noticed the older 4.0 ho exhausts have that huge kink on the exhaust pipe below the header. Is it for back pressure? Seems kinda pointless .

 

[seanyb505]

It's for clearance at full flex .

 

[bjoehandley]

Yup, IIRC, all 4.0 XJ's have that.

 

[aparke4]

For what its worth I have had two cats put on my 97 XJ that didn't have O2 sensor bungs on them. Most muffler shops should carry bungs and can easily cut a hole and weld a bung on it. I haven't thrown a code yet and its been 7 years (5 years on the first one and 2 on the second).

This is the one I have now. http://www.summitracing.com/parts/MPE-54955/?rtype=10
I am pretty happy with it so far does the job and it is small and compact.

yes this - i have done this on one of my XJ's and on a TJ

if you install your self get the cat with 02 bung - otherwise a muffler shop can install the bung for you like mentioned above for very little... that gets you the cat for less since it will be a universal with no 02 bung = cheaper.

 

[bjoehandley]

Well, I've ordered the cat and muffler today, both are 2.5" Magnaflow pieces and picked up a new rear hanger, that will be a PITA to replace..........

 

[bjoehandley]

Here's a XJ from Poland that's probably running a similar cat and muffler to what I've ordered.
http://www.youtube.com/watch?v=5K2i2o5zg9k&feature=related

 

[rckstarTV]

You guys wouldn't happen to have a part number handy for the Magnaflow 2.5" OBD2 legal cat by chance?

i would replace the cat until it goes out. thats a waste of money in my opinion. unless this cat has a bigger inlet and outlet you will gain no power over the stock one

 

[rckstarTV]

I noticed the older 4.0 ho exhausts have that huge kink on the exhaust pipe below the header. Is it for back pressure? Seems kinda pointless .

its not pointless if the manufacturer needed more back psi from the eng.

 

[bjoehandley]

The Cat and Muffler are in!

i would replace the cat until it goes out. thats a waste of money in my opinion. unless this cat has a bigger inlet and outlet you will gain no power over the stock one

The entire exhaust, cat and all, if what the truck left Toledo with 13 years ago and the check engine light is on as well.

its not pointless if the manufacturer needed more back psi from the eng.

It's not for back pressure, it can be hit by the 4wd model's front axle if that pipe wasn't clearanced, it should be pointless on the 2wd models since the front axle is different, but was likely used on there to keep parts consistent for all trucks.

 

[bjoehandley]

Got it all installed yesterday, it does have a slight rattle in somewhere but also seems to breath much better (especially over 4k:shocked: ) that what it did with what was left of the OE system and the Check Engine light went away too.arty: It is a little on the loud side, but it has already mellowed some since yesterday. a friend told me that the one on his Silverado took about a week to mellow from what it first sounded like.