[IronGumby]

Yeah by running that open, that PCV breather is gonna suck unfiltered air into your crankcase. Now sure, it's not being combusted in any way but it is coming in direct contact with your engine oil and everything outside the cylinders.

If you pay for synthetic oil and good oil filters and air filters and so on, to me it would make sense to add this additional protection to your engine so you're filtering it at all entry points.

For an RSX I think you need a 0.75" ID one, like:
https://www.kseriesparts.com/VIB-2164.html
https://www.kseriesparts.com/KN-62-1360.html

 

[IronGumby]

I don't claim to fully understand it, but, the PCV loop is using that port as an intake during the conditions that incur blow-by, which is during WOT (at least). So during idle, yes, apparently the vacuum isn't present and thus there is air coming out, but that is not the path of the oil vapors (it's in through the port over by the alternator that runs to the intake manifold).

 

[IronGumby]

Sure! Yes, please, since most of us don't have one lying around, and especially since this thread is turning to gold real quick :thumbsup:

I had lots of aspirations to explore ram air methods or at least feed an air box with velocity stack inside, etc., but then I found an Injen CAI for next to nothing on CL so I just had to go with it