Any benefit to Add breather to Valve Cover?

[240nspec]

originally posted this in the wrong section, this is the correct repost:

Instead of running a vacuum line from the intake, as most aftermarket intakes do not include the bung for this hose, is there any benefit to remove the hose, cap the intake fitting, and replace with a breather on the Valve cover side?

I know its used to vent, but why vent into the intake?

gains (even minimal)?benefits (again even minimal)?

[krazydriver]

first off that breather doesn't vent. Air is drawn through that, through the engine, and out the pcv system.Pressure after filter accounting for flow loss from the filter let's say it's about 90% of atmospheric pressure(~31in/hg), or 27in/hg.( in the positive direction, this would read ~-3 on a vac/boost gauge)Vacuum in the intake manifold is generally 8in/hgin/hg or -22 in/hg on the vac gauge.So the air is sucking through the breather on the valve cover, through the pcv valve, into the manifold and being burnt.

Replacing it with a breather just makes the intake manifold cleaner, but ONLY will work properly if your running a MAP(manifold absolute pressure) sensor. Otherwise your car will act like it has a huge vacuum leak because of the unmetered air.

[Cone Junky]

What he said^^^, + PCV=Positive Crankcase Ventilation. In this case, "positive" means it uses the intake vacuum to help draw out the vapors.If you vent it, you'll just have crankcase ventilation, which isn't as effective and considered an emissions modification.

[krazydriver]

^ i don't think he was referring to removing the PCV. I think he was just wondering about not using the bung from the intake tube to the valve cover breather. Which is why i made my previous comment about the breather. I stuck a filter on mine and modded the pcv to still feed properly into the intake even under boost... but then again I'm MAP based, so it's not creating a vac leak.

Just to point out though:Completely removing the pcv and just venting the crankcase is retarded. Your oil quality will go to hell REALLY fast. The pcv isn't just emissions, it keeps down windage in the crankcase, which increases horsepower, and keeps your oil cleaner so it lasts longer.Friend of mine pulled all the vac hoses and left his crankcase open to atmosphere from both ends. His oil was BLACK at 500 miles.

[Terrorinc17]

So on my Ka-T I should route it into the intake?

[krazydriver]

I've got some pictures in this thread ( zerothread?id=352281 ) of how i routed mine.That is one of the better ways to keep a pcv on a turbo car. It works in the same way factory subaru turbo cars are setup.