Awesome explanation rmerchant. I appreciate it.

I got 2 ADD W1 baffled cans in hand. One just happens to have a breather and the other is closed loop, so I'm ready to rock.

Ill repost my findings once complete, with pics.

Thanks

 

Why would it be preferable to vent the forward port to atmosphere, rather than running it closed loop as the PCV port is done?

 

The stock closed loop system has the front vent connected to the intake pipe between the air filter and the throttle plate. The pressure in this part of the pipe is atmospheric minus the small pressure drop due to air being pulled through the air filter. This hose is much larger than the PCV hose. Even when the vacuum in the intake manifold is strongest, the smaller PCV hose cannot flow more air than the vent hose. Therefore, the inside of the valve cover (and the crankcase) is always at atmospheric pressure. Having the vent line open to the atmosphere or connected to the intake pipe upstream of the throttle plate or compressor does not change the operation of the system since the vent tube sees atmospheric pressure either way.

At part throttle or idle, the PCV check valve opens due to the vacuum in the intake and the blow by gasses are sucked directly into the intake manifold. If the PCV line flows more air than the blow by produced by the engine, the extra air is provided by the vent line into the valve cover.

On a boosted car, the PCV check valve is closed under boost (or full throttle for NA) and the blow by gasses go out of the valve cover using the only opening available - the vent line. The closed system recirculates these gases back into the intake air stream (boosted or not). They become compressed with the intake air and when the BOV opens they spray around the engine compartment if the BOV is open to the atmosphere, or recirculate if the BOV is plumbed back to the intake.

Having the vent open to the atmosphere keeps these gasses and oil vapor from entering the intake system to be burned and vents them directly to the atmosphere, aversely effecting emissions.

Having a recirculating system in a boosted car puts these gasses back into the intake system in front of the compressor and intercooler to be burned. Of course, it really isn't a true closed system if the BOV (or a waste gate on a SC car) opens to the atmosphere. The down side is that the oil vapor in the blow by gasses may affect the compressor blades and pool in the intercooler over time.

 

Unless you're doing this for emissions as someone mentioned, just vent both lines to atmosphere and call it the day.

 

Here is the breather mounted; vented to the atmosphere.

Got jiggy with some corner brackets from Home Depot, a hammer, and some black primer.

 

Nice and simple. I like. Where are you mounting the pcv one?

 

I put that one on the other side next to the abs. It is just zip-tied until I figure out a bracket off the strut bolt type of thing.

 

Thanks for the advice man. I noticed oil residue on my Vortech V2's impeller then I realised that oil mist was coming from the vent on the valve cover via the pipe provided by Vortech which screws into the plastic elbow for the air filter to attach to. I removed that pipe and placed a small breather directly onto the valve cover's vent while keeping the PCV itself connected to the intake manifold as per stock. I slapped my HKS mushroom filter directly onto the blower eliminating the open hole on the elbow. Is this setup fine?

 

/\ What he said!

 

is it possible the seals in your supercharger are leaking oil and that's what's blowing out your bov? Had the same thing happen to mine, replaced the seals and problem solved.