C_5 Vette

So I recently had lg headers and corsa xtreme exhaust installed I wanted the cats installed as well
the installer said they should be a 3in-let and a 3 out-let and what was sent to me was a 3in-let and a 2.5out-let. I contact the company that I bought them from and they said it should be the 3 to 2.5. The installer does it all the time So I'm leaning more towards him and the seller is not very helpful. So could you guys please help me out ? Thanks in advance

grantv

3" tubes after the cats will likely have no benefit unless you have serious power (extra cubes, big cam, forced induction) I would think.
Did you buy a mid section with 3" tubing though (very common)? If so then 3" thru would obviously make sense for installation reasons.

RVETTE42

I have the Lg Street series headers and recently had LG high flow ceramic cats installed and yes coming off the headers side they are larger than the side that connects to the X-pipe.

neutron82

if you have lg superpros the piping (including the inlet/outlet of the cats) should be 3" all the way to the axle back, from there the flange tapers down to 2.5" so it will bolt to c5 exhaust systems

SAYUNCL

I have LGM long tubes with LGM high flows and they're also 3/2.5 and I'm 2.5 all the way back to my Borla Quad Stingers. After cat install I only dropped 2hp/9ftlbs.



installed LGM high flows