Nissan 370Z Forum - View Single Post - Stock Cat Specs vs Y-Pipe

DarkJak · 07-18-2012, 01:09 AM

Does anyone know for sure what the inlet and outlet sizes are for the stock cats and y pipe?

Seems like some aftermarket HFC's are 2.35" and others are 2.5". How much of an effect on flow would having a switch from 2.35" cats to 2.5" y-pipe be, with regard to turbulence generated by the change in size? And if our stock cats are 2.35" would it be better to mate that to a Y pipe that is 2.35" inlet?

EDIT: Searching lead me to stepped exhaust theory which then lead to this: http://my350z.com/forum/intake-exhau...k-for-n-a.html
Halfway down, very informative, but I'm not sure whether it would apply to my situation.

07-18-2012, 01:09 AM	#1 (permalink)
DarkJak A True Z Fanatic Join Date: Jun 2011 Location: Madison, WI Posts: 1,390 Drives: 2009 370Z Rep Power: 13448	Stock Cat Specs vs Y-Pipe Does anyone know for sure what the inlet and outlet sizes are for the stock cats and y pipe? Seems like some aftermarket HFC's are 2.35" and others are 2.5". How much of an effect on flow would having a switch from 2.35" cats to 2.5" y-pipe be, with regard to turbulence generated by the change in size? And if our stock cats are 2.35" would it be better to mate that to a Y pipe that is 2.35" inlet? EDIT: Searching lead me to stepped exhaust theory which then lead to this: http://my350z.com/forum/intake-exhau...k-for-n-a.html Halfway down, very informative, but I'm not sure whether it would apply to my situation. Last edited by DarkJak; 07-18-2012 at 01:35 AM.