MAF and vented catch can

[builthatch]

ok...

under vac, the intake to valve cover supplies fresh air while the PCV to IM hookup evacuates the crankcase pressures.

under b00st, obviously, the PCV is closed.

this means that the crankcase now vents through the next path of least resistance, which is the valve cover-to-intake tube AFTER the MAF

if you eliminate that connection, and put a vented can to the valve cover, and cap the intake tube connection, the engine will now see air that was previously going to the valve cover under vacuum. it's metered air, and, previously, a bit of this metered air was feeding the crankcase. now it's not, and 100% of the metered air is going to the turbo now.

what i'm trying to prevent is any bulls*** crankcase vapors getting into the intake tube under boost (since the PCV is closed).

a sealed can inline up there is NOT an option because that still includes vapors when the engine sees boost, going into the intake.

how does the ecu typically deal with that metered air going 100% into the engine now, instead of being bled off for the crankcase?

i'm sorry if this is confusing, but hopefully someone understands...

thx

'hatch

 

[tru-boost]

Thats why you dont pit the can up there, it goes down on the pcv side not the breather side. It must be a sealed can obviously. That will allow the can to catch and vapors being drawn in under vacuum as well as catch anything that may seep past the pcv valve under boost. A can on the breather side will not help at all. This car sucks in more oil under vacuum than it does under boost, and with the can up top it wont be able to do a damn thing about it