PumpinIron

I'm in the process of installing a new 2.5 inch Magnaflow catback exhaust system on my 2000 Cherokee. My stock catalytic convertor works fine and doesn't throw any codes but it is rusted beyond belief so I figured this is a good time to replace it with something that not only flows better but will also be 2.5 inches (the same as the catback exhaust).

I've been checking out this Thunderbolt cat from Performance Curve...
http://performance-curve.com/425250.aspx

Seems like it has good reviews and a lot of people speak highly of them. My questions are as follows...

1) Does anyone else use these cats on their Cherokee and how do you like them?

2) My main concern is sound. I don't want this cat to make the Jeep drone or anything. I bought the Magnaflow exhaust because it has a deep sound but it isn't that much louder over the stock exhaust. So, will this cat make the Jeep significantly louder?

3) Anyone know what kind of metal these are made of? I'm hoping stainless steel but I'm guessing it's probably just aluminum.

That about sums it up... Like I said, my main concern is sound. The Magnaflow exhaust system sounds perfect. It's not too loud but also not too quiet. I just don't want to put one of these cats on and have it make it insanely louder or anything crazy.

Just looking for opinions! Thanks guys

Tom95YJ

I run the thunderbolt cat part # 410250 on performance curves website. I also run a magnaflow magnapack muffler part # 10416 with the performance curve tailpipe.

I also have a custom bent 2.5" downpipe and APN header on my Xj. If you go into my build thread I have 2 videos of the sound on the last page that I uploaded yesterday.

The metal is stainless steel. So it won't rust. Asfar as sound with the magnapack and a header mine is a little on the more aggressive side however it is quiet when cruising unless you romp on the gas

PumpinIron

Thanks so much, that's exactly what I wanted to hear. I don't mind an aggressive tone to the exhaust as long as it's only when you get on it. I just don't want it droning around town when you're just cruising on the highway or something, that's what gets annoying.

Also, glad to hear it's stainless. My catback is stainless as well since I don't want any rusting.

Sounds like I'll have a very similar setup to yours since mine is 2.5 inches as well. I'm actually unfamiliar with the downpipes as this is my first Jeep. It doesn't look like they make any aftermarket downpipes from what I can see. I thought I read that the stock downpipe is 2.5 inches though, am I wrong?

Tom95YJ

The stock down pipe is 2.25" and right after the flange where it meets with the manifold it has a kink from the factory to slow the gasses to help heat the cat. I had a custom 2.5" downpipe made.

PumpinIron

Thanks, I wasn't aware of that. Sounds like I'll need to find a good exhaust shop that can make me a nice 2.5 inch mandrel bent downpipe.

peter93xj

I believe that Walker makes a 2.5" downpipe that is factory fit.

PumpinIron

Would this be it? http://www.quadratec.com/products/51403_0023.htm

Doesn't say the dimensions on it... It's cheap though so I'll have to email them and ask if its 2.5 inches.

peter93xj

I'm not sure. Never seen one with 2 pipes. The I was planning to get was in the related section just underneath that. I also don't see any dimensions there either

PumpinIron

I just found out its only 2.25 inches. I don't think anyone makes an aftermarket downpipe that's 2.5 inches.

Tom95YJ

That is correct that is why I had one custom made

PumpinIron

Yep! That's the route I am going to go. I just need to find an exhaust shop that can mandrel bend. Most of the cheap exhaust shops around here don't seem to do that. Or maybe it's just something they make you pay extra for?

Vonguido

Got a question. I too am going to be ordering a new exhaust from them. I have a 98 4.0l XJ AW4 and the down pipe I can have made but do I order the cat with a O2 sensor or not? I have the O2 sensor on the down pipe and then right after the cat between the cat and muffler. I just want to make sure I order the right thing that will work properly without throwing codes.

Tom95YJ

I ordered part# 410250 I added a O2 bung after the cat before the muffler. On my custom downpipe I had a bung added also. I never threw any codes An there is not 1 stock part in my exhaust system other then the hangars

Vonguido

This is great news! Thanks I will definitely order then. My exhaust is rusted to crap and the tailpipe at the metal hanger rusted through and came off so this is a needed fix cause I can't hear myself think when driving lol.

84zmyfavorite

The 2 pipe downpipe design is what 2000 and 2001 Cherokee 4.0s have, after their cast iron 2 piece exhaust manifold.