I just purchased a set of altima headers on ebay Link and am having a custom y pipe made for them. Basically doing the same thing 95BLKMAX did.
What size piping should I use for the y pipe? 95BLKMAX used two 2" sections merged into 2.5". Should I bump it up to two 2.25" sections merged into a 3"? My other mods are 00vi, EU, and 3" Exhaust. Headwork and cams are in the cars future.

Any insight on this would be greatly appreciated.

 

I vote for 2.25" into 3".

 

Are you making the y-pipe equal length?
Is this for a 5.5 gen?

 

2.25" into 3" imo. Probably not optimal for stock setup, but with cams and headwork you'll want as much exhaust flow as possible.

 

holy crap those long tube altima 3.5 headers are super cheap!.

 

cats out the bag i guess... in for pics

 

Lol, its been outta the bag for years in the so flo

 

Got a little present in the mail today.

 

I'm doing 2.25->2.75, unless you make a 3" test pipe and the inlet to your catback 3".