I have purchased a spare intake manifold. The new manifold has rubber hoses and they connect into one hose with a quick disconnect on the end. My original manifold doesn't have these hoses. What are they used for ?

 

Here's a photo of it

 

From all my research on OCCs, that's where the PCV port from the valve cover hooks up. This was changed to eliminate oil pooling in the throttle body on the N14.

 

So I use my original plumbing for the pcv system I take it ?

 

So this is the older style set up before they chose the one big hose to the back of the valve cover

 

I don't have hands on experience with this as I have an N18. With that said - IIRC, this is the new version. The hose connects to the PCV port on the back/passenger side of the valve cover, the existing hose that goes to the throttle body has to be plugged. The reason for this is with the original design of the valve cover with integrated PCV valve, there was far too much oil coming out and causing carbon build up, also oil/water vapor was condensing and pooling in the throttle body. So the new plumbing for the PCV vent eliminates the pooling problem but not the carbon build up. Apparently there's a new version of the valve cover that improves things.

Also from what I have read, it appears that most people who install OCCs on the N14 install it on the front valve cover port that goes to the turbo inlet, and some plug the back port, which then can cause oil consumption problems. It seems to me that the OCC would be much more effective on the back port.