y pipe diameter?
 

what is the diameter of the stock y pipe on a 1997 z28 with the dual cats? i just got a really good deal on a 2.5 inch y pipe with dual high flow cats. just wondering if i will feel much of a difference over stock. the car has shorty headers and B&B tri flow exhaust. will this make the car much louder? i kinda want it to be just a bit louder. thanks.

Re: y pipe diameter?
 

I'm not sure the diameter but im willing to guess its around 2 inches maybe a little more. You should feel a difference by the SOTP way.... it might be a little louder.

Re: y pipe diameter?
 

I think the 96-97 dual cat y-pipe is 2-1/4" piping. But the real restriction is where the 2 pipes come together and connect to the cat-back. It necks down to 2-1/2" where it connects to the intermediate pipe. A 2-1/2" dual cat y-pipe with a 2-3/4" or 3" connector to the cat-back will make a difference in overall flow. But it would be hard to put hp numbers on it.