PCV valve delete?

[BuddySpeed3]

I've finally figured out that my turbo smokes when back pressure in the catless downpipe drops during deceleration in gear above 3k rpm, and in between shifts during throttle lift off.

What do u guys think of replacing the pcv valve with a higher flowing check valve from Damond Motorsports?

I would simply block off the pcv valve with a cap, and then run that hose to another port on the pcv plate. The check valve at the intake manifold will now become the pcv valve with reduced restriction.
@Fstrnyou; mentioned that he had tried this setup with no issues. I just wanted to get a few more opinions

I figure that more vacuum needs to be pulled on the crankcase to overcome the lack of back pressure in the downpipe during decel and lift off to prevent oil from being drawn past the turbine seal and blowing blue smoke.

Thoughts?

[JSmith]

You will sink your vacuum at idle, and pull all sorts of oil into the IM if you put in a check valve that flows too freely.

[BuddySpeed3]

Originally Posted by JSmith You will sink your vacuum at idle, and pull all sorts of oil into the IM if you put in a check valve that flows too freely.

Thanks for the response man! I've got the OCC in place, so that would keep oil out of the IM. The check valve would be the one that Damond Motorsports provided with the OCC. So definitely less restrictive than the PCV valve.

I'm wondering if having the PCV valve out of the equation will pull a stronger vacuum on the crankcase during decel and throttle lift off to prevent oil from being pulled past the turbo seal when back pressure in the downpipe drops.

Do u have experience with this?

I'm planning on measuring crankcase pressure by hooking up my AEM digital boost gauge to a modified oil filler cap to see what difference a setup like this would make with vacuum on the crankcase.

[JSmith]

I had an OCC in place too. Still sunk vacuum and got oil in the IM. Wasnt using a DM check valve though.

Where is vacuum applied to the turbo when it could possibly affect oil sealing?

[BuddySpeed3]

Which check valve were u using?

Vacuum on the turbos oil drain during deceleration and throttle lift off between shifts. Pressure goes from high to low, so if there is barely any back pressure in the downpipe, oil might take the path of least resistance which might be past the seal an into the exhaust

[JSmith]

Can confirm that this model will NOT work out well without the OEM PCV valve.

https://www.jegs.com/i/Earls/361/251010/10002/-1

[BuddySpeed3]

Originally Posted by JSmith Can confirm that this model will NOT work out well without the OEM PCV valve. https://www.jegs.com/i/Earls/361/251010/10002/-1

I think the oem pcv valve might be more important than I thought in terms of regulating vacuum on the crankcase. Maybe having too much pull from the intake manifold can cause problems like you had with oil in the intake.

The smoking seems to have stopped after I emptied out my OCC but it was dark outside so my judgement could have been flawed. A little bit more that normal came out. Maybe it was frozen in there due to the colder temps causing a blockage. I installed the DM dual catch cans just this past summer so this is the first time they are seeing the cold. As usual only the OCC going to the IM had oil in it. The other vented can always has nothing. I'm gonna do more testing after winter and keep this thread updated. Tbh I'm tired of beating this issue to death but I'm obsessed with this car so...

[Fstrnyou]

My catch can for the valve cover was always empty as well.

That Earls check valve is designed for fuel. Fuel has a lot more mass than air, so it's possible that a little bit of airflow doesn't create enough force to push the flapper shut.

[JSmith]

One of the reasons I went with that check valve was that it had a published spec for pressure to seal. 0.5 PSI is a pretty low threshold.