Turbo Header/Manifold

[mateopdx]

I am working on building a turbo manifold and was wondering what is the best inside diameter of piping to use? What is the wall thickness you guys and ladies suggest? I am thinking I will just do a log type manifold, any pointers?

Thanks!
Matt

 

[Does10s]

Primaries = 1 5/8" (or 1.5" if you've got a 200 or smaller) Both will work fine.
Main log = 2.5"

Use 14 guage mild steel or if you've got a TIG and a few more dollars, pony up for Stainless.

Anything thinner will crack over time. Even the 14g mild steel will crack eventually.

Will