What size of pipe would I need to make the cat on my 95 Z28 disappear? Thanks in advance.

 

Why not just punch the honey comb crap out and save the $$ on an off road design ? It's pretty much the same thing.

 

I am not sure of what it will sound like with a gutted out cat.

 

I have an aftermarket exhaust with a 3 inch I pipe. The factory Y-pipe is I think a sorta oval shaped 3 inch pipe. I just went to autozone and got a pipe with a 3 inch outside diameter flare on one end and a 3 inch inside diameter flare on the other end about 18 inches long. I first cut the cat off at the weld where the Y-pipe went together into one pipe. Slid the inside diameter 18 inch pipe over the Y(actually pounded it on), and of course put the outside diameter one into the 3 inch I pipe. Welded everything up and tada, makeshift off road pipe. Works perfect.

 

It sounds great man, alot of people do it. I mean I guess it would flow a little better with an off road pipe replacement but I really don't think it would be enough to notice at all. Besides if you just gut the cat, you get that cool sounding wistle under the passenger floor board. It's up to you man, I just always took the cheapest rout when it came to the cat.