MangoSwisher

I removed my cat AND muffler and it’s loud as ****, but notice a difference in driving idk if it’s mandela effect but does it add power or is it because there’s no restriction? and recommend me good exhaust systems that aren’t gonna burn up my wallet

SirCyber

Ooof that's a touchy subject here. many people here are against cat deletes, mostly due to them being illegal in many, if not most places. I personally don't care, so here's my take.
#1, go HERE and input your information so that people can assist you. many parts are interchangeable throughout the years, but not all. Exhaust headers changed a few times, and so we would need to know what your jeep is.
#2, you don't need super expensive exhaust systems on your jeep. It's simply not pushing the heat and pressure of a sports car. If you have an earlier style jeep and the straight six, you will notice your exhaust header cracks between 4 and 5. This header is a great option for fixing it.

rest is up to you. are you looking for a specific sound? similar to stock?

Jim Malcolm

I'm running either a Magnaflow 10416 (satin) or a 14416 (natural) with a Dynomax 55014 tailpipe I feel like it's the natural version, but the satin is cheaper... I liked the sound from a Borla 40357 (2-1/4") better, but, ...

Here's a inexpensive high flow cat

https://www.summitracing.com/parts/flo-2000125

That Jeep Guy XJMJ

https://www.motortrend.com/how-to/15...ing-true-lies/

This is a referenceable link i've come back to many times over the years when it comes to gains with the 4.0. Few exhaust pointers in there

robsjeep

The criminal class thanks to soft on crime judges have caused many Cat Deletes. The honest working class can no longer afford replacing their deleted cats.

FlyinRyan

Why is that so much money? I put the same one on my 99 for $87 from amazon. Same header

Huh?

robsjeep

Translation....if the courts locked up the cat crooks big time, we will see a drastic reduction in cat stealing. Instead it often is a slap on the wrist crime thanks to soft on crime prosecutors and judges, The result is little if any jail time even for repeat offenders, hence it has become a low risk, high reward criminal activity.
Lock them up and the crime rate will go way down. They used to hang horse thieves, not saying we necessarily need to go that far, but if the cat thieves were facing five years in prison for the first offense, and 20 years for repeats, I think the theft rate will go way way down.

vroomvroom

Yes, removing your muffler and cat will free up a little bit of horsepower. Is it worth it? Heck no! Way too loud, way too smelly, and it's illegal. Plus, XJs aren't racecars. What would you do with an extra 10 ponies? Not much.

If you want it a bit louder, get a proper exhaust system.

UKXJ

So, do you have any recommendations? That's what OP was asking for, right from the start.

vroomvroom

Yes, Walker and Dynomax make a full exhaust system for our XJs.

Me personally, I took it to a shop and gave them a Thrush muffler. It has some rumble to it but won't wake the neighbors up. I'd recommend your local exhaust shop.

danej1026

I purchased my Cherokee with the cat removed and I cannot stand the noise. It could be just the Dynomax muffler but I have to assume that the missing cat has something to do with it. I am not sure what it would take to install another cat outside of the cat itself but there is no indication on the dashboard of any bells and whistles going off. Any advise?

vroomvroom

Can you give us some pictures of your exhaust system? That would better help us.

danej1026

vroomvroom

Thanks for that. That's a pretty wide aftermarket crossmember. Right behind the crossmember is the only location I can see where it would fit. They will cut the exhuast system right after the crossmember and weld the cat in place then cut off pipe equivalent to the length of the cat and weld the rest of the exhaust system back in place. Ultimately, having a cat and muffler will help with smell and sound a lot. Having just a cat and no muffler would help with smell and noise a lot more than no cat with muffler, like you have now.

There needs to be an O2 bung hole welded onto a section of pipe after the cat and you will need to find your O2 sensor wiring if it's even still there. I don't see it personally unless it is tucked under the floor on the inside. The O2 sensor isn't absolutely necessary if it isn't there. It just monitors the cat for efficiency. If you can't find the O2 sensor, don't worry about the O2 bung either.

UKXJ

My latest XJ also came without a cat (there's just a piece of pipe where it would've been) & 'though the exhaust note might be a little different (aggressive?) it's not noticeably louder than the those with full systems - but it does have (as far as I can tell) the original muffler.

At least I know now why the homeless O2 sensor doesn't trip the CEL. Might unplug it, see if that makes any difference &, if it doesn't, I'll remove it, just to tidy up the underside.