A intersting Video about pcv hose size vs crankcase pressure

[gti 130 wow]

https://www.youtube.com/watch?v=lZOhdBUiRyw

 

[IDoSeaDoo]

Ha! I made that video last year when I was testing what size fitting i could get away with using on my 1997 challenger 4tec conversion. 1/4" barb was building so much pressure, it shut down the engine and blew oil out the valve covers. Made a huge mess!

 

[gti 130 wow]

I noticed on a car the normal air input for the pcv system is at the value cover and the suction comes from the pcv valve location. If the amount of blow by goes way up then the air flow changes direction and the run from the valve cover to the air intake can go from being a output to a input. I see know plan b for these engines so this may be a hidden place to gain some free hp.

 

[IDoSeaDoo]

The pcv systems used to vent to the atmosphere, but epa mandated that those gasses be captured and burned in the combustion chamber. Hence we see pcv hoses go from the valve cover to the intake piping. Intake pipes always have low pressure due to the engine sucking air, and hence the flow is always from valve cover to intake. Some pcv valves have a one way valve, which I think is to protect against backfires.

 

[gti 130 wow]

I looked again and I don't see a hose from the valve cover to the intake that makes having the right hose as you said critical.

 

[gti 130 wow]

The pcv valve restricts flow during idle or your engine will stop running.

 

[IDoSeaDoo]

Don't know about that, but i know that sometimes that pcv hose doesn't come from the valve cover. The Rotax engine is a great example. The pcv hose just has to attach to a location that is connected to the crankcase, where it can releive the blow by gasses and is not likely to suck oil (though that's practically unavoidable as oil vapors will always be present in there).