I've noticed that some single turbos have a nipple on the compressor side. for a small diameter hose.
My R85 doesn't have a nipple.

My tial sport waste gate has a nipple,what does that hook up to?
And on top of the waste gate, it has a srew that screw in the top and has two holes on the side, and the top of the scre is closed, what is the purpose of it?

 

This turbo for example

https://www.rx7club.com/showthread.php?t=694065

 

The nipple can be a point to read boost pressure. I dont want to comment on the wastegate.

 

The ports on the wastegate hook up to the boost controller solenoid and the intake somewhere. They are used to control boost. See your boost controller instructions for what to hook up where.

- Andy

 

Thanks, I found out that i'm missing the air fitting on the top. That's why the screw has the holes.