My muffler and alot of the exhaust mount hardware is almost totally shot on my 2001 4.0L with about 150k miles.

Intake to tailpipe is totally stock except for a K&N air filter.

Do you think it's "worth it" to replace cat back or even headers to tailpipe when I repair this shyt?...or would you suggest to forget chasing any incremental HP and torque, and just replace the muffler and mount hardware with minimal cost. If the former, any good setups you recommend?

Appreciate your suggestions..

 

It depends on your budget. I wouldn't chase horsepower with XJ for me it would come down to the sound and quality of the replacement parts. I would complete an inspection of the complete exhaust system to begin and then replace what needs to be replaced.

 

I struggled with that question myself. '00. CA Emissions. I was getting a P0432. I also needed a new muffler and tailpipe. High flow cats maybe. Should I get a header since I am replacing the cat. Borla muffler and tailpipe maybe. With a decent header running about $350, $425 for the Borla, and Magnaflow high flow cats being through the roof said screw it. For a stock 4.0 with just a 4 hole injector upgrade figured it was not worth it. Just replaced the whole exhaust, front cat back, with Walker parts and called it a day. Now I toy with the idea about getting a motor built by a place local to me. Maybe not a stroker per se but a motor with a little something. Awhile back the opportunity to buy a TUPY head presented itself. $50. No idea of the condition. They would handle that for me too. If I were to go forward and do that then when it comes to exhaust I would bite the bullet and spend the money.

 

Do you have to pass an emissions test/inspection? The '01 has pre cats in the manifold, so, you may need to keep them. If not, a header, or even a manifold from a different year might be an improvement. The OEM "manifold" is already a header style, and if you don't have the pre-cats, I would never spend the money on an aftermarket header. WAY too expensive for too little gain. The factory design is not bad here.

With that said it might throw a code or something without the pre-cats, I'm not sure about those. I'm just glad I don't have any.

Aftermarket free flow cats are not very expensive. You can also get money for scrapping your OEM cat, it's full of precious metals. There are a lot of mufflers out there that sound way better than stock if you aren't going for silence...

 

it's a jeep, i like to keep them quiet. so i go stock replacement, walker parts.

for my harley... loud pipes save lives.

 

It's also the famous 4.0 inline 6, that comes with a very distinctive sound. It sounds very nice with the right muffler. It sounds like a broken UPS truck with the wrong exhaust. I like to let the sound out, but that's personal preference. (personally, I don't like unmuffled harleys)

As for "it's a jeep", Jeeps are supposed to make noise. It's not a Kia. Even the stock exhaust isn't exactly quiet...

 

IF you really want to hear a sad exhaust you should hear my 84 xj v6. The PO simply cut the exhaust off at the transmission mount. Said he was just using it around the ranch and didn't want to spend the money to replace the muffler.

Needless to say, when I get around to building it, I will be going back with the stock configuration. Nothing worse wheeling in the beauty of the mountains and listening to a AA fuel Dragster trying to cross a river....YUCK!

Don't get me wrong, loud has its place. I have a Harley and it's loud for a reason. That reason being I can let the cages on the road know I'm there. I don't abuse the loudness, but it's there if I need it.

Just my .02 worth.

Happy Jeepin'

 

If you want it not loud any oem replacement muffler well do,As far as any power gained from exhaust upgrades you might get 5hp which youll never really feel.

 

I was in the same situation as you. My Muffler was rotted and falling down. I looked online for the best deals. I listened to a lot of sound clips with different mufflers and tail pipes. The one that I liked the most was the Thrush Glass pack. I found one on craigslist for $15. The difference that I made is that I went with one that is for a larger vehicle. it is 2.5" diameter and 28 inches long. The one recommended for the Jeep is 2.25" diameter and 26 inches long. I have stock cat and tail pipe so 2.25" diameter. The larger diameter and longer length help give it a deeper sound then the standard glass pack. It gives a nice sound wile accelerating and is pretty quiet wile on the highway. It also has a nice tone wile at idle. I like the louder muffler in my jeep because I live out in the woods and there are a lot of critters that like to jump in the road.

 

I had an exhaust shop run 2.25 inch pipe from the headers back then I put a cheap $30 ebay muffler on it. It sounds good and cost me less than $120.
http://www.ebay.com/itm/Single-Chamb...dVbgdw&vxp=mtr

 

Stock replacement Walker from Advance Auto. I'm grown now, I don't wanna hear a loud exhaust anymore.

 

I agree, I almost went with a flowmaster setup from PerformanceCurve because the price was so low, but I managed to get a stock style replacement from a local shop, installed for $80.
It actually sounds pretty good, almost "stock+" if you will

Price was low, and I like my rig quiet for when I am wheeling in places I am not really supposed to

 

Maybe im getting old but im starting to like a not so loud exhaust now a days,Younger i always have glass packs on everything then spintech mufflers which are louder.Driving a loud car everyday can get anoyying and ring your ears,And worse case you could get electric exhaust cutouts if you want it loud and not at times.

 

i agree. even when i was younger, i had a 340 duster with headers and quiet mufflers until i opened it up.

loud mufflers are on underpowered cars/trucks and just annoying. good for kids.

my harley has stock pipes, for now, but v&h pipes and screamin eagle breather coming soon. but it's only a sporty, wanna keep it calm. next will be a glide with some grunt.

 

what do I do when half the exhaust is bad? Chop after the cat and put a short pipe with a turn down on it. cheap, CA legal, and sounds the same as a cherry bomb anyway. factory replacement exhaust manifold and downpipe from rockauto if necessary