Hey im wondering what size piping what you use for a custom build manifold for the vq35. Im going to build my own manifold to bring over to the turbo in the batter area. im going to do three into one design. I have a setup similar but in just mild steel piping with log cast manifolds now on my dek,but from each side going to a twin scroll turbo. what size would you use from the head to the colector and from the colector to the turbo one side( rember twin scoll)

 

I've been wondering the same thing lately. My GUESS would be 2"

To take advantage of the twin scroll, you'll definitely want to keep it equal length between the two manifolds. You'll also have to keep the two pipes completely separated which will create a little bit of a problem if you're going to use an external WG. My suggestion would be to make a small Y-pipe for a single WG or use two WG's. You probably already know all of this...

 

2" is way to big for an individual cylinder, 1.75" at the very most. I use 1.5" in the manifolds I have built. I'm pretty sure you want smaller piping for pre-turbo pipes. I'll search and see if I can find the exact article with explainations.

2" or 2.5" for the collector to the inlet flange will be fine.

 

I thought that he was only wanting to know what size piping to use from the collector to the inlet flange (I read his post too quickly...) and that's why I said 2"....