higgsy91

Right so i'm after a decat pipe for a ZT conv. It's got all the running gear from a FRS so obviously i can pick a decat pipe up off the shelf.

My question is.. i have seen some that are 2.75" which flow better.. a) will this even fit to the flexi? and b) will the sudden step down in size cause pressure and give a little blow past the gasket..

This is probably stupid shit, but i'd rather buy once not twice.

Cheers Lads!

pani_k

iTrader: (1)

What is the bore size of the rest of your system?

SBT83

If the flange is made to bolt in the cats place then it will fit. I don't think pressure will cause a problem as cats are very restrictive so in theory that would build pressure as the gas try's to escape through it. And that would more than likely cause a blow with hot gas trying to escape where it can, but that doesn't cause a blow. So you'll be ok I reckon . Just make sure the de cat pipe is the same diameter as your exhaust.
I will say that make sure you fit flanges on straights and not on bends. I had a full stainless made that had de-cat and it had a joint on the down pipe bend that was forever blowing gaskets it soon got sorted after an argument

higgsy91

It's a 2.5" (standard size)
But i think SBT83 cleared up everything here! 2.5" decat it is! Good that you got your decat sorted, scream loud enough and you will always get what you want!