Exhaust Diameter

I have a '96 with 4.0L. I'm wanting to order a new catalytic convertor and muffler, but am unsure as to the stock exhaust diameter. My XJ is about 50 miles from here getting lower gears installed, so I can't crawl under it and measure. From my searching here, I THINK that it is 2.25" from the manifold all the way out.

I'm pretty sure that I read on here that I'd be better off to go with 2.25" from the manifold to the catalytic convertor, then 2.5" from the cat on out. Opinions? Does my XJ's cat have the 02 sensor bung? The two cats I'm looking at are the Magnaflow 91036 (bung) and 91006 (non-bung). Which do I need?

The mufflers I'm looking at are the Dynomax 17748 (2 1/2") and the Dynomax 17747 (2 1/4").

I went with 2.5 inch diameter from the bottom of the headers all the way back, didnt loose any back pressure or anything. The jeep really has some get up and go now. I also have headers and an intake so that would help get more air through the exhaust.

Stock is 2.5" to the convertor, 2 1/4" out and back.

http://info.rockauto.com/Walker/Detail.html?128-2630.jpg

winterbeater said:

Stock is 2.5" to the convertor, 2 1/4" out and back.

http://info.rockauto.com/Walker/Detail.html?128-2630.jpg

Click to expand...

So is my 1996. Then I bought Rustys Catback which is 2.5" all the way back. I did not like the droneing at some RPM's. I changed the straight piece next to the fuel tank to 2.25 and eliminated most of the droneing. I do like the Rustys cat back with the FM 50 though. With the exception of the 2.5" pipe out back I would definately buy it again.

The stock 4L AW4 moans all the time when you accelerate a little in traffic. Muwaaaaaaaaaaaaaaah, coast, muwaaaaaaaaaaaaaa. And often shifting at pretty stupid times. Not nearly as bad when you are on it hard. It's not really the kind of an exhaust note that you want to make louder.