TwinTurbo.NET: Nissan 300ZX forum - Am I understanding your logic?
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Subject Am I understanding your logic?
     
Posted by enthuZiast on April 19, 2011 at 7:03 PM
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In Reply To PCV System, Explained, Deleted >>> posted by Ash's Z on April 19, 2011 at 04:21 PM
     
Message My interpretation of ASH pcv delete-mod:

For comparison, OEM setup:

Intake manifold under vacuum:
- PCV sucked open and vents positive crankcase pressure into intake manifold.
- Front tubes vent positive crankcase pressure into turbo inlet pipe which is essentially open to the atmosphere.

Intake manifold pressurized (boost):
- PCV pushed closed via boost pressure.
- Front tubes vent positive pressure into turbo inlet pipe which is essentially open to the atmosphere.

ASH setup:
Deletes the PCV, so the front tubes are the only routes the positive crankcase exits during vacuum and pressurized(boost) situation.

This "delete-mod" is based on the assumption that there will always be positive pressure coming from the crankcase; raising RPM will only create more positive pressure.

My question is, if the front tubes are elevated high enough and provide sufficient ventilation of positive crankcase pressure, why did Nissan think it was needed for the redundant PCV system at the back of the valve covers? They did not spend R&D money for no reason. And, they already have a method of venting positive crankcase pressure via front tubes; so they have already abide by the law.

     
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