I installed the US STi shortblock into my '02 WRX. It has an additional breather on top of the block that is situated directly behind the throttle body. When I initially did the swap, I just vented it to atmosphere. I had a 'phantom' oil leak in that oil was consistently pooling on top of the block...I'd clean it off and it would promptly come back, presumably while under boost.
My suspicion was obviously the hose that I had hooked to the extra breather, so I first tried plugging it, then tried routing it into my catch can. Problem not solved. I checked the oil pressure sensor on the top front of the block, it was tight. I checked the 'Y' router on the other crankcase breather hole, it was seated properly with the 2 hoses coming off of it clamped properly. Also, I had somehow gotten it into my head that that Y was the PCV valve. I'm embarrased to admit that it was only in the last couple of months that a friend pointed out where the actual PCV valve was located, and I'm now pretty certain based on the condition of it, that it is where my pooling oil problem stemmed from. It was never routed anywhere, just sticking out of the intake manifold most likely blowing oil all over the place.
I'm reusing my old WRX intake manifold/throttle body on the EJ257, so I went ahead and ordered the entire PCV 'kit' and to be honest, it's not immediately apparent how IT is supposed to be routed. There's also an electrical connecter that I have no idea what plugs into it. I believe that the hose that the elec connector is attached to is supposed to be routed to the stock airbox, but I no longer use the old airbox.
My question is, is it an incorrect assumption that I can just route everything (heads, both crankcase breathers, and PCV) to the catch can, or are there some considerations that I'm not aware of that would dictate that I route everything in a completely different fashion?
Does anyone have any good positive crankcase ventilation resources you could point me to so that I can do some research on my own?
Thanks