mudfrog

To my knowledge there is nothing "Double Walled" on the exhaust from the factory. Also, he cannot be building his own high flow cats unless he is gutting something. He could be building something but either way it's going to be illegal as I'm sure a random muffler shop is not going to be an EPA approved manufacturer of catalytic converters.

Diesel

Short ram, TB spacers, high flow cats=marketing tricks.

Very rarely do you see HP gains in a jeep, alot of people think just cause it responds quicker, or accelerates smoother that they have HP/tq increases. When in reality it was just the vehicle not running to its fullest ability before hand and thats the performance they got used to.

mudfrog

This is false. There are true high flow converters. While they do not make a huge difference they do exist.

zeep99xj

Yeah i guess he was blowing smoke up my *****. So what is the best type of cat? Whats the deal with spun style cat converters like the thunderbolt and i think magnaflow makes one too.

Diesel

Go with a Magnaflow series50, and cat.

djb383

That's a great article (better than the dude that wrote it realizes)... I'd be locking for one of those 200 vs 700 cell cats in a heartbeat (I prefer the 1 cell cat). Only problem is, most muff shops/places to order/buy a cat are gonna give you that "blank look...huh" response when you start talking substrate cells per sq in.

One cell cat () into a straight thru stainless Magnaflow #12256 and out to the side......about as low restriction as u can get and still very quiet.

EMAXX620

yes, hes (mudfrog) is a vendor on the forums. Ive seen a handful of people running his catback setups (2.5") and everyone loves it.

edit:: he also posted in this thread

and about if highflow cats exist or not, never looked into it much, but this one i believe is straight thru with the packing around the outside "offroad only." was looking at it when i was going to do my dakotas.
http://www.car-sound.com/02product/universal/race.asp

96_xj

choose a different muffler shop.


$100 for the cat(i only paid $40)-magna flow high flow cat 2.5" in/out
$40 for the muffler(paid $30)-cherry bomb glass pack 2.5" in/out
$40 for the mandrel bent 2.5" exhaust all welded with new bungs for o2 sensors.

did it while i waited/watched.

and mud frog is a trustworthy vender on here.






http://www.youtube.com/watch?v=http:...?v=4IiVsCGSiBI[/QUOTE]

zeep99xj

Which series of magnaflow cat is the right application to fit the xj?
http://performance-curve.com/magnafl...onverters.aspx

1904-96xj

Here's the best exhaust modification you could ever have...a Plug and Play if you will:

mudfrog

Any of them except the pre-converters will work.

The 94105 for oval body or 59955 if you want the spun version. Assuming your staying with 2.25"

It will come down to which style / size would work best for you.

djb383

You need to decide between staying with stock exhaust 2.25" or stepping up to 2.5" when choosing a cat. Stock size cat is 2.5" in and 2.25" out. Also, the cat needs to have the O2 bung toward the rear so the stock sensor can be screwed in. With 2.5" exhaust u need a cat that's 2.5" in/out and a muff that's 2.5" center in/2.5" offset out. Here's a pic of stock exhaust/dimensions.

zeep99xj

I am going to step up to 2.5". So performance wise all of those cats are the same? Whats the difference between the spun converter and the others?

zeep99xj

Im having trouble finding the flomaster original 40 series in a 2.5" center in offset out. I checked performance curve jegs and summit. Anyone know where to find one? I did find the super 40 in what i need, what do you guys think about that series instead of the original as far as sound and performance?

Diesel

Its deep. Mainly made for 8cyl engines, raspy and muffled on 6cyl.