I made an oil catch can for a B18B with three nipple inputs. Two is for the two oil nipples that come out of the valve cover. The other one (people stick it in their intake), is not recommended to be put into the intake when using with turbo. Is it important that I link it back into the car? Or can I just leave it hanging somewhere so the fume just leaves?

 

You have to have it plugged up if it isn't being used or you will have a nasty vacuum leak.

All you need is one hose going from the breather tank and the other going to the intake manifold for a basic oil catch can. You have to have one hose connected to the intake or else there won't be any suction drawing the oil vapors into the can.