Does a car need a PVC valve?

The PCV valve is designed to prevent oil vapor being spewed into the air while eliminating crankcase pressure. As previously stated, it will prevent oil from being forced through the various engine seals.

- But it is also supposed to increase power. Prior to the creation of the PCV valves, the crankcase pressure was relieved by means of a 'dump tube' directed down the back of the motor. It simply allowed internal vapors to blow out of the engine and into the air unfiltered. Using a PCV setup is actually a better way to pull that pressure out.

Using breathers alone can often be sufficient to release internal pressure. - But often it will mean using more breathers to accomplish as much.

For some of our drag motors we would install crankcase evacuation systems which are designed somewhat similarly. But instead of having the engine's vacuum pulling out the internal crankcase pressure you run a hose assembly down to your exhaust and the exhaust pulls the pressure out with even more suction. The crankcase evacuation systems were supposed to actually create a negative pressure inside the crankcase and make even more power yet. Not exactly as environmentally friendly though.