Thread: Crank Case Ventilation fully explained. (Turbocharged edition.)

but ben, a few of the german cars do exh PCV setups... could you theorize theyre operation.

Yah, from the N/A thread they are just going for this solution.
It works the same for turbo setups.

so using that reasoning, 2 litre turbo should disconnect any source connecting to the turbo intake?

Yes.

But he said he already tried that, and wasn't having the results he'd hoped for. Which is why he changed it up.
He is seeing better results now, and I imagine that is because the intake port provides more vacuum than the exhaust on his setup, which means the exhaust check valve is shut the entire time making that side unused in the system.

I'm pretty sure that the check valve is just shut at all times to be honest. The hose past the check valve is bone dry. I'll be removing it this week, before going in for the tune. And just capping the inlet on the downpipe. It was just a quick fix and I haven't corrected it yet, lol. On the intake side, I literally have miniscule oil residue. Not even enough to show any kind of shiny reflective surface. I have awesome ring seal (thanks to using the TQ plate while machining the block), so I'm very thankful for that!

Update: Check valve is now removed, ha ha.

Today while I was doing a boost leak test, I noticed how badly the VE/RR PCV valve was leaking. Replaced it with another one I had which had low miles, still leaking, much less though. Tested a DE one that I had before, leaking as much as the newer VE one, which I would equate to having a paperclip sized hole in one of the silicon couplers. It's a big enough leak to mess with the max boost on a small turbo and overpressure the crankcase (I was down 1.5 psi at redline on a t25 just from going to VE valve cover from DET one).

At first I thought about making another inline check valve with ball and spring, just like manual boost controller is. But then I reconsidered the traditional PCV system altogether. Why not just add it to the valve cover breather, then send it to the valve cover breather, which eventually will go to turbo intake. With this configuration there should be a constant vacuum provided to the PCV valve, especially in boost. This should help reduce the crankcase pressure, not by much but it will definitely stop adding on to it due to leaky OEM PCV valves!



Better route would be to use an oil catch can of course.






I for the life of me could not get this to work on my turbo VE, gave up on trying, not enough room to find a good spot for it either.

Vadim, you might as well have just capped off that end. Pretty much the same result.

Haven't done anything yet, but you don't think it will help evacuate the crancase pressure under load? Or is the vacuum from turbo not nearly as powerful? (I should test this out with my boost gauge!)

Let me know when you see ~20 in/hg at idle from intake tube.