I've had this combo for a while now, and have had a terminal issue of bad fitment and exhaust leaks. Yesterday I noticed I had a loud sputtering exhaust leak on the left joint between the cats/y-pipe, that was quite loud. We put the car up on the lift today and noticed that the gasket was blown out.

The problem with the combination, is that the flange on the Kinetix cats is about 1/2 inch smaller in diameter than the flange on the y-pipe. We went ahead and changed it out with a smaller sprayed gasket, and put on some locking washers, but it was still leaking very slightly. Right now with the mismatching flanges, it's going to be difficult to get a proper seal that doesn't leak.

I was thinking of looking for some thicker gaskets, possibly the kind with the rings in the middle. Has anyone else dealt with this, and possibly know a way to get a better seal without fabricating a new flange for the cats?

Thanks in advance.

 

Thats interesting, does the gruppe pipe have 2.5" inlets or 2.25" inlets?

Ours is 2.25", have you tried factory gaskets? They are made to fit with the fasctory y-pipe, so the factory gaskets could be your best bet