I have the stock exhaust run up to my stacks and a 5 inch crosspipe in the bed. what Im wanting to do is get the DE downpipe, a 4 inch cat delete pipe and my question is if I should run 4 inch or 5 inch from the delete pipe up to the cross pipe? right now I have a 4 inch pipe coming down through the bed to a 3.5 reducer. Is there a sound difference with the 4 and 5? I know LBZs seem to have a sound of their own and the louder I can have it the better. Plus Id like to drop the EGTs a bit. Thanks

no one huh? is there a difference in 4 or 5 inch sound on a LBZ?

anyone own an LBZ?

Probably not many people have had a 4" and a 5" inch on the same truck to compare. I would bet you anything the 5" would have a deeper louder sound.

Run 4'', its easier, more room.

I have a 4'' Down pipe , which connected to an MBRP 5'' exhaust. Sounded awesome.

Then when i added a my 5'' stack ( 4'' connection) i kept some of the MBRP 5'' from the down pipe, then reduced to a 4'' Flex pipe with 2 4'' 90*'s up to the stack.

Still loud and actually im going to redo it to all 4'' and add a muffler.

The short of it is since you have stacks it doesnt matter if you go 4 or 5. I'd go 4'' and make it easier to hook up your stacks.

alright well thank yall

well i dont have an lbz nor have i had one...but i have had an lmm w/ 4'' and an lmm w/ 5''. both sounded good......5'' is def deeper at cruising speed mostly, and looks cool. 5'' is harder to install not alot of room. and i do notice a little drone at about 1600rpms.

Cool, Im gonna go with the downpipe to a 4 inch front pipe and run the rest 5 up into the stacks. We'll so what happens I guess

Just my personal observation....the smaller the pipe, the louder and "snapper" it is. snappy sound as apposed to deeper , mellow sound with larger pipe.

When it comes to EGT's, the bigger the pipe and the shorter they are equals lower temps.