Fiesta ST PCV Modification Idea.. Input required.

[Joelgray2]

Hi all, after trawling through thread after thread of discussion regarding the PCV system, I think i've managed to come to terms with how it works and a possible solution that would work better than VTA, yet still keep the PCV and CCV system entirely separated from the intake.

I have attached a very poorly drawn sketch of how I think everything could work.

It involves:
Completely deleting line 1 (Left, PCV) and capping off both ends
Capping off line 2 (right, CCV) at the intake, and re-assigning the port where it used to connect to on the engine by placing a hose which would run to a venturi fitting in the exhaust which would provide a small vacuum, w/ check valve.
Replacing oil cap with a breather that allows air to flow freely into (or out of, in the event of no vacuum from the venturi fitting) the crank cover, effectively doing the job that line 2 used to do, bringing in fresh air while the PCV side of the system was venting.



Also just wondering what the third pipe in the middle that connects the cover to something near the crankcase does?

I think this will be effective because the PCV system no longer has any connection I can see to the intake system, meaning there should be no unmetered air loss/gain.
The system needs to be effective because the car is primarily a daily driver.

To answer some questions:
I am aware its illegal
I want to avoid the use of catch cans


It's a bit out there so just wanted some input from someone in the know.
Cheers

 

[A7xogg]

I have always seen people who run breather oil caps have burning oil issues in the future. You'll want to have each side open because there is alot of blow by pressure with a turbo engine so u'll want to keep each side open. If pcv valve fails, just replace it. Are you trying to possibly limit carbon build up while keeping a working pcv system? It's not a bad idea but my personal experience and knowledge has told me oil breather caps are a no

 

[felopr]

Umm, so you are going to cap the crackcase ventilation hole on a turbo car? doesnt sound smart IMO
by the way that third hole is for the "Crankcase Vent Oil Separator "

 

[Joelgray2]

I did not realise the two were entirely separated? I assumed that if the PCV side was blocked all pressure would just head out the CCV (right line 2) side instead? someone enlighten me

 

[A7xogg]

I did not realise the two were entirely separated? I assumed that if the PCV side was blocked all pressure would just head out the CCV (right line 2) side instead? someone enlighten me

ur right but i would say its too much pressure for one line. If we were na it would be fine but were not

 

[felopr]

ur right but i would say its too much pressure for one line. If we were na it would be fine but were not

This.
Look at it this way, tue left hose takes care of the crankcase and the right hose takes care of the upper head area. Is true what you are saying but on a turbo car, it creates a lot of internal pressure especially under boost in the crankcase so it needs all the help it can get. By capping 1 hole you are you are straining the ventilation system, especially more the way you want to so it since, the crankcase pressure have to travel from the crankcase thru the head thru the holes that are used for draining oil from the head back to the crankcase, well you get the idea.
I think is important for the intake to help the pvc crankcase (intake vacuum pumping out), this eliminates blow by, witch is good, but is not so good because the oil gases go back to the combustion chamber via the intake.
I think that is why is always good to run a catch can on a turbo system, and a pretty good one like the damon catch can with vta option.
Under manifold vaccum, intake vacuum helps the pcv export out the pressure, but the air pressure gets filtered (via the catch can) before the air enters the intake manifold. Under boost, the inline check valve that comes with the catch can kit prevents pressure from going from the intake manifold to the catch can / pcv hole but at the same time the catch can has a check valve that open while on boost to vent to atmosphere the crankcase pressure. I think this is the best compromise if you run ur car daily.
The other hole the intake /valve cover hole is not gonna see a lot of pressure or hardly any with a well ventilated pcv side. Soke people cap that and put a filter in the valve cover or in the oil fill plug (like the cfm). The problem with the cfm is that it has a check valve, and since the head hardly has any pressure it hardly open, so you are not venting the head area, you need some in there also.
This is all my opinion, i understand it like this, if i am wrong please tell me

 

[Bluedrank]

Just going to chime in and say that this seems like a really bad idea. But, you're welcome to start capping off the PCV system and let us know what codes you throw and/or how long your motor lasted.