Positive Crankcase Ventilation System (PCV)

I know this has been done before but out of curiosity I was just wondering which PCV plumbing options would be the best to use. The closed circuit system with pressure being exerted on one end and vacuum on the other or the closed circuit system with the only drive for the system being provided by vacuum. My question too is that in the old post by Haberdasher


he used a PCV valve in top of the catch can but on this site


I think it’s a open 90* in top of the catch can. So which one is it open 90* or a PCV in top of the catchcan? and which PCV plumbing option do people find better to use in there set up?

I second that question.

You can use either of those options, and there are also some others. If you look in the forced induction forum on Honda-Tech there is a HUGE thread and some very good write ups about different PCV setups.

Thank you but i checked that too I’m just confused if I should put PCV on top of the Moroso catchcan or just a open 90*.

Just run pcv free tubes from the VC and PCV box.

In the back i’m putting a open 90* where the PCV usually go and put a PCV in top of the moroso catchcan. Haberdashers diagram

PCV valve in the top of the catch can is going to the intake pre-turbo (it’s the only place there is vacuum under all intake conditions). If it didn’t the crank case wouldn’t be under vacuum when the intake was under boost, when it is most important the the crank case be under vacuum. If the tube from the PCV valve in the top of the catch can went into the intake manifold the PCV valve would close when under boost, shutting down the PCV system and cause damage to the piston rings.

More about PCV
Thank you.