Ok folks I have a 01 XJ sport. Ive had it a few months and well have had issues. So im changing the head, got the clearwater one new cast. Also replacing the exhaust header with Exhaust Header Ceramic Coated 4.0L Rugged Ridge. Got a great price on it. And while i was at it picked up Flowmaster Super 44 with tailpipe from performance curve, what a steal of a price. So now with the CEL on with po432 i figure there is only 2 other things to replace and thats the pre- cats and main cat.

So i have found 2 pre-cats. EASTERN CATALYTIC Part # 20376 or WALKER Part # 52304 w/Aftermarket Extensions Pipe 53440
So which one have you folks used and with what results?

So on the main cat, id like something like the thunderbolt but have seen it in 3", now if im correct we have a 2.25" from the precats and super 44 is a 2.5".
So whats do most do with this, expand it and reduce it?

Thanks for any info and help fellow XJ'ers.

 

There are only two precats. The third one is a resonator then there is a muffler- at least that what everything I have researched says.

 

Hummm, ok so the 3rd one before the muffler, a resonator is there a replacement or can we do without. I havent found any info on that, i thought it was cat lol. Thank for the reply

 

It doesn't cause any restriction in airflow just smooths out the tone so no real reason to remove it. I dented mine pretty bad though so I have considered replacing it with straight pipe.