3in exhaust and cat converter

This is a CAT converter





.

Most only go 2 and half inch and leave the cat converter in , I don't think there is any benefit in having 3"

If you look around the wreckers, you should be able to get a cat converter off a Holden V8 that is 2 3/4 or 2 7/8 If I was changing the exhaust size the change the lot other wise you might as well leave it.

to achieve any benefits, you will need a high flow CAT Conv. otherwise it will restrict the exhaust and as already mentioned, render the rest of the exhaust upgrade almost pointless.

There has been a lot of discussion recently about exhaust upgrades for both the 3L and 4.2L on the Patrol forum

There are some schools of thought that the 3L is best with a 2.5" to 2 3/4" (no additional gains going to 3") where as the 4.2L is happy to take as much as it can get.

Hope you are doing the extractors as well?

Mickpaj,
You'd be a goose if you didn't google Beaudesert Exhausts.
Jeff.
ps . Ignore Doug's cat converter: the man's obsessed. jh.