I am swapping an S5 turbo onto my S4 turboII and have a couple of questions. Since the S5 manifold doesn't have an actuator in it what do I do with the line that went to the S4 manifold actuator?
Should I cap it or just leave it open?

I have searched but haven't found any info or write ups on how to put an S5 turbo onto an S4.

 

use the S5 Turbo and Manifold.
the S4 and S5 manifolds are specific for each turbo(s4 to s4 and s5 to s5) they are not interchangeable.The turbo flanges are different.So you can't put an s5 turbo on an S4 manifold,and Vice versa.
You can run the Vacuum hose from the wastegate to to the Turbo compressor inlet.
If you wish to put a Boost controller in between them it is ok to do.,

 

Umm... I think he's asking about the twin scroll actuator.

I would cap the line and just leave it. Otherwise you introduce a leak into the system and that's never good.

 

That is what I wanted to know thank you.