This is being argued on another site I'm on....Basically...I need to know if it is dangerous to not have your valve cover breather vented. I have a catchcan installed like this:



I'm being told that the breather should be open to atmosphere or i'll ---- my ---- up. On the other hand i'm being told there is so much blow-by at the breather on a boosted honda, theres not reason to worry. Thoughts?

 

vacuum on the valve cover breather is ok... thats what it is stock. They only problem would come from if it was being pressurized, and from a quick glance at your diagram, it doesn't look like it is

 

if your conserned just open it up

 

The two locations I circled don't really make sense to me (keep in mind I'm a noob) but it seems like you would be able to just plug off the opening at the top of the drawing and eliminate the need for the lower line...

 

You could do that, but then 100% of the remaining vapors coming from the catchcan would be coming out the exhaust eventually leading to some smokage. This way, when theres vacuum, it mimics the stock PCV system and routes it back into the motor. Thats what makes it a 2-way setup, and 2-way owns 1-way, ya heard?