The oil catch can is an item that many people think they need, but don't really. The OEM PCV and valve cover nipple work together to make sure that there is always homeostasis in the crankcase as far as pressure is concerned. The PCV is inline between the intake manifold and the valve cover and is a one-way check valve. Under positive intake manifold pressure (on boost) the check valve closes and the crankcase fumes are routed out of the valve cover nipple that goes to the intake. The vacuum created by the turbocharger suction aids in evacuating the crankcase of pressure and fumes created by combustion. When off-boost, the reverse happens. The negative pressure in the intake manifold (vacuum) sucks the crankcase fumes into the intake manifold and back into the engine to be re-combusted, thus aiding in less unburnt fumes to be emitted into the atmosphere. Fresh air is sucked into the crankcase by the vacuum created by the PCV through the valve cover nipple attached to the intake. The system helps ensure that pressure will not build up excessively in the crankcase, which will definitely lead to a piston ring-job in the extended future.
SiC, the way you have it set up, I am a little concerned, mostly at the way AMS did not create a provision for the valve cover nipple to be re-routed to the intake pipe. The stage that your motor is in right now, does not require the use of an oil catch can. You'll find that you're not really going to have that much collecting in the can. I can 100% guarantee you that you'll catch more water vapor in the can from the car sitting over-night than you will catch oil. Also, it looks like the can you have in there is an eBay special. Those cans have no substrate inside them to actually 'catch' the oil. By that I mean, a good catch can has to have something like steel wool or the like inside, because when the fumes go into the catch can, they are in hot gaseous form and when they contact a cool metal, the oil condenses on the substrate and will eventually drip down to the bottom of the catch can, thus doing it's job. I have seen those cans that you are using on the car and have cut them open to see if anything is actually in there. I found nothing but an empty can. Totally useless. The way the catch can is installed is partially correct. The nipple that you have just venting to air on the catch can will still force the fumes into your engine bay, and over time it will leave a nice misting of oil. And then you will have a nice layer of grime in your engine bay, as the dirt and airborne particles will stick to the layer of oil. That nipple should be routed to a nipple on the intake pipe so that the suction caused by the turbocharger will allow the fumes to be 'sucked' through the catch can, rather than 'pushed' by the crankcase pressure. The added stress of the motor having to 'push' the crankcase fumes through the valve cover nipple when under boost is something that can add to the likelihood of rings going bad before they should on a stock application.
Please, take nothing I say in the wrong way. I am not here to offend or belittle people. I just want to share my experience with a multitude of modifications that I have dealt with in the past and the results and would rather you do it right the first time than have to regret things later on.
