PCV System Questions

[jasong_10]

I've been going through the collection of threads we have on here regarding catch cans and came across some info on the OEM PCV system.

1. Normal driving/no boost it operates by pulling clean air from the intake tube pre-turbo into the front bank (clean side) and it exits the rear bank (dirty side) and is routed back into the intake post-turbo/pre-TB.

2. Under boost, the PCV closes

and/or

3. the circulation reverses.

I have a '12 PP, can anyone verify if any or all of this information is true for my application? Thank you.

 

[FrankK]

I'm pretty sure it's 2. Otherwise under boost you would over pressurize the motor.

 

[jasong_10]

That makes sense, reversing circulation maybe wasn't the right way to word it, one of the posts mentioned that with the PCV closed under boost, it causes "dirty air" to be pulled out of the "clean side"/front bank pre-turbo. Where as under non-boost conditions it is the entry point for clean air heading to the crankcase, hence the "clean side" label.

 

[FrankK]

I'm not certain, but I think that clean air goes through the air filter first, then on to the turbos.

 

[withku]

That makes sense, reversing circulation maybe wasn't the right way to word it, one of the posts mentioned that with the PCV closed under boost, it causes "dirty air" to be pulled out of the "clean side"/front bank pre-turbo. Where as under non-boost conditions it is the entry point for clean air heading to the crankcase, hence the "clean side" label.

pcv only flows one way, just closes under boost.

bank 2 replaces air in the crankcase due to vacuum.

 

[jasong_10]

pcv only flows one way, just closes under boost.

bank 2 replaces air in the crankcase due to vacuum.

So is there a PCV/one way on both banks, one on the rear that only lets air out, and one on the front that only lets air in?

 

[FrankK]

Here is a good article explaining how the PCV system works on a turbo charged engine.

Blog : Stratified Automotive Controls

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Frank

 

[jasong_10]

Here is a good article explaining how the PCV system works on a turbo charged engine.

Blog : Stratified Automotive Controls

Stratified Automotive Controls : Blog - Sensors Decals and Swag Water-Methanol Injection BMW Subaru WRX and STI STRATIFIED Products Gift Certificates Spark Plugs & Coils Porsche DYNO and SHOP Reservation Flash Tuning Tools BRZ / GR86 / GT86 VW / AUDI FORD Nissan/Infiniti Honda / Acura GR...

www.stratifiedauto.com

Frank

Thank you, that cleared things up (if I'm understanding it correctly). The way I read it, in non-boost situations the vacuum from the intake pulls the pressure from the rear bank/"dirty side" out of PCV and into the intake. Not sure what the front/"clean side" PCV does . . .

Under boost the rear/"dirty side" PCV closes and the vacuum from the turbos pulls the pressure out of the front/"clean side" PCV into the intake track.

I'm just curious as to whether or not my car has the OEM oil/vapor separators that the article mentions.