valve cover hose and maf question

[eddiec]

is it necessary in cars equipped with maf's to have the valve cover vent hose go to the intake? is there any issues with vacuum lose or any other potentially performance hindering consequences if it is vented to the atmosphere through a small breather filter.

[justmerging]

You can vent it but only if you plug the hole in the intake pipe. Otherwise it will run like a$$ because it's sucking in unmetered air. If you want to dress it up just put a colored silicone hose in there.

[gumby]

breather filter? please expalain. im somewhat clueless when it comes to crankcase ventilation. the pcv valve lets gas through into the plenum and keeps oil out right? does the valve cover hose let oil or just gas into the intake on a stock car for instance? i thought oil catch cans were only for turbos and other major HP setup.

[eddiec]

i put a filter on the end of that valve cover vent and plugged the intake where it went to.

i'm more curious to find out if there is some kind of power loss by having this pressure from the valve cover being vented to the air. i put the filter on there after i realized that it was spitting oilly gunk into the intake and causing the throttle plate to stick a little.