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A few things that have been bugging me. Thanks.

1) Is a PCV valve *itself* just a glorified "check valve" ? I understand the part about letting crankcase gases into the intake, via the PCV and the hose... but as far as the actual valve itself, it has no job to do other than let vacuum through one way but not boost the other way. Is that right?

1.1) If yes to 1, then is there any PCV valve, for any car/year/I don't care, which incorporates a small spring to keep it normally "closed", up to say 1 or 2 lbs/in ?

2) If vapors are being slurped FROM the crankcase, then it stands to reason that vapors must be going INTO the crankcase at some other place. It just stands to reason. So where exactly is fresh air coming INTO the crankcase?

3) At the sucking side of the PCV valve, the vacuum is split between the crankcase and a tube going down to the DIRTY SIDE of the airbox, where there's a little place for a gimmicky filter to be crammed into a hole just for the PCV intake. Why didn't they just connect that tube to the CLEAN side of the airbox and cut through the madness?
 

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1) yep its just a one way check valve
1.1)I have not taken any apart so not sure if any have springs. I know some neon guys like the Supra turbo replacement pcv valve. McMaster carr has some low cracking pressure check valves but not sure if they have springs either.
2) well the vapors are blow bye from the combustion gases that get past the rings during combustion
3)the intake side is not sucking in fresh air, meaning this side is for when the motor is in boost and the pcv valve shuts, then the turbo creates suction to vent the vapors, so they put it before the little filter and the air filter so the oil doesnt get into the turbo

There is many debatable theories on crankcase ventilation

The Honda turbo guys dont use pcv or check valves, just large dia hose(carries less oil with the vapor) that vents to keep pressure less then 4psi
 
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