About 2 inches below at the oil filler neck, there's a small hose connection.
Where is this connection should go? Is it to the vacuum?

 

It's been awhile since I've had a rotary, but if memory serves me correctly, that's part of the crank case ventilation system and connects to the UIM.

 

yes, i do believe this is what youre talking about. the "crank case" vent. is it pointing down? is there another one above it that that is routed to the uim with the a big *** check valve?

or are you talking about something below the filler neck and not on it?

posting pictures always helps

 

Sorry for the late picture.
The blue hose is the one I'm asking where to be connected.
The black hose is a stock and I never touch it. Still in the original location.
Thank you

 

That one runs through a series of soft and hard lines and ends up at your forward turbo inlet. One of the 2 vacuum lines from there is that line. Looking at the vacuum diagram, that hose is labeled A and where it ends up on the turbo inlet isnt labeled anything. Its just an outline.

 

Well, I'm single turbo now...can i put that blue hose to a vacuum?
It looks like the black hose has a one way valve and I think the blue hose needs a vacuum to make the black hose works?

 

You can actually run both of those hoses from the filler neck to a catch can or you can run just the blue one to a catch can and vent the the other end of the catch can or you can just leave the nipple open

 

As always CR-REX thank you !