PCV system theory and Oil catch cans.
Evolving Member
Joined: Sep 2005
Posts: 178
Likes: 0
From: NY
In my system, I removed the PCV to avoid the vapours to dirty my beautiful engine...
AND I routed one of the two pipes in front of the BOV to have some ventilation under the valve cover every time the bov opens ;-)
AND I routed one of the two pipes in front of the BOV to have some ventilation under the valve cover every time the bov opens ;-)
My 2cents.
I always retain the stock PCV if it is the type that is compatible with turbocharged cars. Positive intake pressure will cause the PCV to shut as to not place pressure within the block. However, while cruising and at idle the intake will pull vacuum from the block.
Under boost the PCV shuts down and we now need another method by which to evacuate the block. How, using the turbo inlet to pull a vacuum. Run the block to a catch can and then to the turbo inlet. You need to baffle in such a way as to not suck in from the can to the turbo inlet. Under boost the can may fill with oil. Place a drain on the can to the oil pan or turbo drail. Place a one way valve in the drain so under boost the can does not draw oil from the block. This method is tried and true and on the twinturbo ZR1 I recently completed we measured 2in-mg at the catch can with 7.5psi of boost. I have a diagram somewhere, but cannot seem to locate it at this time. I do have some PCV setup pics.
The pic below was the ZR1 setup. We did not drain back to the pan, but did check from time to time and saw no oil within the catch can.
This is the setup on my old twinturbo 240z. It did drain back into the pan and collected oil from time to time.
I always retain the stock PCV if it is the type that is compatible with turbocharged cars. Positive intake pressure will cause the PCV to shut as to not place pressure within the block. However, while cruising and at idle the intake will pull vacuum from the block.
Under boost the PCV shuts down and we now need another method by which to evacuate the block. How, using the turbo inlet to pull a vacuum. Run the block to a catch can and then to the turbo inlet. You need to baffle in such a way as to not suck in from the can to the turbo inlet. Under boost the can may fill with oil. Place a drain on the can to the oil pan or turbo drail. Place a one way valve in the drain so under boost the can does not draw oil from the block. This method is tried and true and on the twinturbo ZR1 I recently completed we measured 2in-mg at the catch can with 7.5psi of boost. I have a diagram somewhere, but cannot seem to locate it at this time. I do have some PCV setup pics.
The pic below was the ZR1 setup. We did not drain back to the pan, but did check from time to time and saw no oil within the catch can.
This is the setup on my old twinturbo 240z. It did drain back into the pan and collected oil from time to time.
Originally Posted by denial
PCV off the valve cover:
You can see my lines for my can. Just find the stock hose and follow it back. You'll see where it hits the intake manifold.
You can see my lines for my can. Just find the stock hose and follow it back. You'll see where it hits the intake manifold.
Newbie
Joined: Sep 2005
Posts: 1
Likes: 0
From: B.C
I dont own an EVO.. but still a OEM turbo car so i'm trying to understand the pcv systems between us. I'm wondering if the EVO has any crankcase ventilation ports on the block, or is it just one on the valve cover?
wtf?
Originally Posted by flyingstick
I dont own an EVO.. but still a OEM turbo car so i'm trying to understand the pcv systems between us. I'm wondering if the EVO has any crankcase ventilation ports on the block, or is it just one on the valve cover?
Please read the whole thread before you post. And take a look at the little picture thingys.
Just as some food for thought...
...the new MK5 GTI's and Jetta GLI's with the 2.0T FSI engine are having some PCV issues.
Their situation is entirely different, however, in that the PCV system on that engine DOES NOT drain back into the intake tract before the turbo. It drains back into the pressurized intake manifold.
The issue is that the intake manifold pressure is such that it is reverting back through the PCV system into the crankcase. With roughly 20 PSI leaking back into your crank case, where do you think it will go?
It will blow straight out of your oil cap, of course.
So, essentially, the PCV system is causing a leak in boost pressure from the intake manifold.
The simple solution that someone came up with was to put a one-way in-line check valve into the line between the PCV valve and the intake manifold. It's a good idea, but it needs some refining.
We're developing a sturdier solution to offer to these folks.
Though this is not directly related to the Evo, I just thought some of you might be interested.
(and yes, the intake manifold on the 2.0T FSI VW engine IS plastic)
...the new MK5 GTI's and Jetta GLI's with the 2.0T FSI engine are having some PCV issues.
Their situation is entirely different, however, in that the PCV system on that engine DOES NOT drain back into the intake tract before the turbo. It drains back into the pressurized intake manifold.
The issue is that the intake manifold pressure is such that it is reverting back through the PCV system into the crankcase. With roughly 20 PSI leaking back into your crank case, where do you think it will go?
It will blow straight out of your oil cap, of course.
So, essentially, the PCV system is causing a leak in boost pressure from the intake manifold.
The simple solution that someone came up with was to put a one-way in-line check valve into the line between the PCV valve and the intake manifold. It's a good idea, but it needs some refining.
We're developing a sturdier solution to offer to these folks.
Though this is not directly related to the Evo, I just thought some of you might be interested.
(and yes, the intake manifold on the 2.0T FSI VW engine IS plastic)
Nothing new...BMW has been doing plastic intakes for 10+ years. Allows for better control of the shape during manufacturing and smoother bores in the manifold. There are plastics out there that are MORE than strong enough and heat resistant for these applications.
ya I believe the alot of the new gm cars are platic too. Corvetts have been for a couple years I believe. They dont heat up like cast ones. I never seen one on a boosted car though.
I just created a How To mount the DC3 and will add pictures shortly....Tell me what you guys think....
https://www.evolutionm.net/forums/sh...52#post3727852
I have two recommendations for the DC3 -- (1) More tubing if you use my mounting location and (2) longer L bracket to attach to the firewall but have the cans below the strut bar
https://www.evolutionm.net/forums/sh...52#post3727852
I have two recommendations for the DC3 -- (1) More tubing if you use my mounting location and (2) longer L bracket to attach to the firewall but have the cans below the strut bar
You will will have to undo the pipe and hose clamps of course.
Stick your finger in there and see if they is any oil present.
If there is oil present, it is reducing the ability to cool the air passing through.
This is actually more prevalent in a brand new Evo.