Turbocube

Alright, so my XJ has an OEM exhaust system complete with rusted, cracked, cast-iron exhaust manifold, ridiculously restrictive downpipe, 18-year-old catalytic converter that complies to California law (this post may cause cancer), rusty stock muffler, and tailpipe that is almost as far from the rear bumper as it is from the road...

So, I'm thinking this is a great time to overhaul the entire exhaust system. I'm going to use this thread to attract older, wiser members who would be kind enough to bestow their knowledge.

Anyhow, down to business. I adhere to two principles in how I look at my relationship with my vehicle; 1) Don't replace, upgrade. 2) Do it yourself, learn and have fun. Only problem is, I've never touched a welder. So, while I know I can replace the exhaust manifold myself, I know I also can't finish the job. Any advice on how to go about getting the exhaust system welded together and installed while still doing most of the work myself? Of course I'd be thrilled to learn to weld myself, but I don't think I'd want to use my amateur knowledge on my exhaust...

I also am looking for guidance and suggestions on choosing the proper parts.

Exhaust Headers ~ Definitely want something higher performance than the stock manifold, but I also can't afford a Borla exhaust system. I figure almost any headers will be considerably more efficient than the standard manifold (correct me if I'm wrong!) so my main concern here is getting one that has been proven reliable and won't crack. I'd also like to keep the cost under $300 for the new headers/manifold if possible.

Catalytic Converter ~ I seem to recall seeing somewhere online, cats being sold that are built to be highly efficient at moving the exhaust through, to the point that they aren't even legal in California. Well, if its not legal in Cali, it must be awesome, so I want one!

Muffler ~ Okay, I'm going to be very honest with you guys. I kind of want something obnoxious. But only when I want to be - if I'm going WOT, I want it to be loud, but if I'm just cruising on the highway or driving to work, I don't want a Super 44 drone in the cabin, if that makes sense. I'm looking for a sound closer to the Flowmaster Outlaw than the Super Series. Any suggestions?

2.5" Diameter Pipe ~ Widening the diameter of the exhaust piping the whole way back seems like, with my very basic knowledge, to be a good idea. I figure if I buy the above parts separately I can also buy the pipe separately, and it be less expensive than a complete kit. Is this a correct assumption?

Thanks in advance to everyone!

98cherokee531

I can chime in and say that my 98 sport has a nice throaty sound using a knock off flow master 40 series muffler. It's the same muffler as an original 40 just doesn't say flow master and it cost me 38 bucks. My tubing is still 2.25 and I wish to move up to 2.5 but it sounds good as is. I do not get any drone inside the cab either. I have a spectre cowl intake as well and when you have it at wot between the intake and exhaust it sounds good for a i6

98XJ40K

Check out Performance Curve, vendor on here is Mudfrog. He has great deals on FM/MF mufflers with 2.5" mandrel bent tailpipe. You can get that setup for ~$105. Also has a wide variety of cats.

He also stocks all sizes of pipe and mandrel bends. You can get the ones you need, cut to fit, and have someone weld it up for you. Or you can use a bunch of clamps... Either way, you can do most yourself.

As for the header, a stainless header by APN from ineedparts.com for ~$160 ish. I have it and have zero complaints.

You might want to check out another guy on here for a bored throttle body, his name is thexjfiles or xjfiles, ~$50 after you return you core.

And if you need a 99+ intake manifold to help with all that new airflow, hit me up. I just happen to have one I'm about to take off a donor XJ.

Hope this helps!

EZEARL

I just put a cat-back system on my '96 about 2wks ago. Instead of taking it and having it welded I used lap joint band clamps w/hi temp rtv in the 3 slip joints. No leaks or movement at the seams so far.

yarom

X2 on performance curve. Great pricing....

98XJ40K

There is a sticky in this section about mufflers and exhaust that has hundreds of posts with good info as well.

Turbocube

Thanks guys. Hey 98XJ40K (nice to see I'm not the only Full-Time RWD XJ driver on the board ) - Thanks for the recommendations. I like how this is adding up. Only concern is the collector diameter on the headers, 2.25", if I'm using 2.5" piping it seems a little weird. What's you guys' take on that issue?

So I've been told that using clamps to assemble an exhaust may work but is inferior in all ways to welding. Is this true? I would prefer to be able to use clamps and do it all myself but, I don't want the thing to fall apart.

Finally, any suggestions the catalytic? I live in Florida (no mandatory vehicle inspections) if that helps...

P.S. ~ I'm sure that if I did decide to swap my intake manifold, other parts/sensors would be needed, correct? How difficult is this process for a beginner?

cleenrob

here let me run you through my current set up:
-APN exhaust manifold
-Walker downpipe(no crush after the collecter)
-Magnaflow cat
-Flowmaster 40
-rustys mandrel bent 2.5'' tail pipe

overall i like my set up flows wayy better than stock at least. id like it to be a little quiter tho. i will say that you should have a custom mandrel bent down pipe made. my walker pipe is less restricive than the stock one, but still has some ugly bends in it and could be better.

its probly a good idea to grab a new o2 sensor (NTK) whilst your redoing the whole system

EZEARL

Welding would be better than clamps but,like you,I wanted to do it myself. Plus I wanted to be able to replace components if need be. On the washboard roads I drive plus the 1/2mi steep washed out driveway to the house just MAYBE they'll loosen or leak but I'll deal with it then. So far I'm impressed with'em.

98XJ40K

The collector is 2.25" on the APN, but you can transition to 2.5" on the downpipe with an adapter.

As for welded vs clamps, I intend to have mine welded, but it will be in sections with clamps in certain points so I don't have to remove the entire exhaust to do maintenance. Just my preference there.

Turbocube

Good point about the downpipe, cleenrob. I'd almost forgotten. I really hate that thing. Before I joined the forum, I was sure that I had damaged it myself while driving, from a rock being thrown up there and hitting it. I was shocked that its OEM.

You guys have a good point about the clamps making maintenance easier. Well, I figure I'll go with clamps and if they suck then I'll deal with that. Do you guys use Loctite or anything on the clamp bolts? Assuming anything like that would be heat-resistant enough.

I wonder if there isn't a downpipe with a 2.25" flange for the manifold and a 2.5" end going to the cat...

EZEARL

I didn't use Loctite on the bolts. To "hopefully" make sure the clamps won't move I sprayed brake cleaner on the areas of the pipe,muffler,and converter where the clamps would go. I used hi temp RTV at the seams only and forced it back into the seam as best I could. Then tightened the clamps. They do get tight.