At what point do you remove PCV valve and run just breathers?

[drag-n-cuda]

I'm at about 400 hp at crank and have disabled pcv and have breathers on both valve covers. Only drawback I see is a little more oil on valve covers just below breathers, but the floor of my intake is clean. When do you go from pcv to none, but not all the way to a header evacuation system?

Thanks,
drag-n

[rumblefish360]

I still run the PVC myself. Breathers in the other spots.
I figure a little vaccum in there could only help keep it clean.

I guess I would draw the line at strip only.

[pishta]

Old Fords has a breather tube that ran down to the bottom of the engine bay and had a diagonal cut at the end that produced a vacuum when they drove, like an evacuator but not using the exhaust to provide the air stream. You could always run the breather line up into your air cleaner, there is a small amount of vacuum in there, not much though.

[6 packin]

I would say on a high reving race engine, that uses a E-Vac system from the headers to help vent the case, I wouldnt think that ditching the PCV all togather would help anything, only to remove oil from the carb (most setups) to the exhaust. It does help prempote ring seal, which race engines are known to be loose and burn oil anyway. I think Hooker sells them for around $100, the parts could be had at way cheaper at the local auto parts store, if you know what to ask for.

[ehostler]

The only time you should remove the PCV system is when going to an evac system. There really is no in between stage.

If you were getting a lot of oil in your intake, with the PCV, then I would think that the baffle has been removed from the valve cover.

[Slingshot383]

If you're running a blower or a turbo, there might be more internal pressure developed than what either a PCV or an evac system can get rid of, then you have to use either a vacuum pump or blowdown tubes.

[flipper35]

If you are tight on your octane requirement. Oil vapor reduces the octane a bit. Can't think of any other reason.

[Dr. Righteous]

I have seen people punch out the baffle so they can put their fancy breathers in the holes. Well, that lets oil get into your intake. Cheap aftermarket valve covers usually cause interference with your breather and PCV valve.
In my case, I wacked the baffle down so the breater would clear, but kept it functional.