Extreme Crankcase Vacuum: Yes or No?

[raceman6135]

In theory, the K&N-style breather you have on the driver's side valve cover should flow more than enough air.

Is that filtre plugged? Is there something inside the grommet that is preventing air to flow into the crankcase? I've seen instances where a closed grommet (one that is supposed to be cut open to the proper size by the end user) was used in error, which prevented airflow.

As for which way is better between a stand-alone breather or one that is plumbed into the bottom of the Moroso filtre housing, I think it's just a matter of preference.

With the tube connected to the inside of the filtre housing, any excessive oil mist (blow-by) that the PCV system cannot handle will be deposited inside the air filtre housing. With the open breather, the oil mist accumulates on the top of the valve cover, making it look messy.