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

Of course. You will never really have any vacuum on the crank case. Ring seal during off-boost suffers, among other things. This is a terrible idea. Reading and comprehending these threads should have made that abundantly clear.

Terrible idea. No different really from blocking off the PCV route. Maybe a little worse since you're messing with the factory catch can in odd ways.

You mean keeping oil from entering the combustion chamber?
This might help a tiny bit, but it is bad in many other ways. What you need is a dedicated catch can for the PCV side like shown here: http://www.sr20-forum.com/usergallery/1594c6c124897062.png

Copied over from the N/A thread:

This defeats the entire purpose of having that smaller PCV line. If you're not going to hook it up to the intake plenum after the throttle body, then it is pointless. You might as well just cap it off (not a good idea). You'll only get a tiny bit of vacuum hooking things up this way, and this is how the WOT line is hooked up anyway. You've now made it redundant.

im about to change over to a VE valve cover on my DET

im designing a catch can system for my car right now, im going ot use a dual catch can system isolating the valve cover from the block,

the crank case ventilation will go to a sealed can that will evacuate out the exhaust via a moroso crankcase evacuation kit (i am using 2 of these kits because the check valves can fail) i can also run another evacuation route via the turbo inlet incase both those check valves fail) the can will be custom built and very well baffled, this will be a returnless system so no oil will be returned to the block


the pressures under the valve cover will then vent to a vented can via 10 an lines,

Forced, just so you know, you can't truly isolate the valve cover from the block. There will always be the timing chain route.

i know but i also know that pressure goes from high to low so that will determine the flow

im going to attach vacuum pressure gauge to the system and seee whats going on

Hi Ben

Thanks for the effort in putting together these guides! Currently my setup is that a line runs from the T to a catch can, which then has a breather. As you have pointed out this is not a good setup, as theres not enough vaccum, so I want to change it.

One option is to run the line to the catch can, then run a line from there to the intake, so similar to stock.

However I am also wanting to clean up my engine bay a bit and make it look nicer, so I was thinking of a setup similar to the following, but instead of a breather, have it plumbed back into the intake. How would that work?




Finally, what do you think of the following setup, from Zilvia (SR Owners... More HP Easy Mod... Catch Can Setup - Page 7 - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum)



Essentially, the T is no longer a T, and a new fitting is welded onto the valve cover (could you also drill and tap, and maybe seal with araldite?). The bit from the T goes to the crank case, and on the top goes to the catch can

Hi guys

Thanks so much for this guide and the NA one, I've read it thoroughly and learned that you should leave the PCV untouched, and its best not to vent to atmosphere.

I've seen some setups where the catch can has a breather on it, and also vents to the intake, whats the point of that? And what about connecting the PCV to the catch can too, and venting to the intake? Or best to just leave the PCV alone?

I'm in the process of setting up my catch can, and just wanted to know your thoughts on the following setup:



But have it connected to the intake rather than having a filter. So essentially, connect one side of the T to the catch can, block off the other side (just replace with an AN fitting), and connect the crankcase to the catch can too. The way I see it, the crank case vents to the T, so this way it vents directly to a catch can. Is that right?

And what about the following setup from Zilvia, thoughts on it:



So the crank case connects to the T, and an AN fitting is welded on top (could you just drill and tap, then epoxy for a proper seal since I dont have access to a TIG), and the top vents to a catch can which then connects to the intake.

Thanks for your help

Saad

saad, I'd love to help you out. Can you let me know if either of those valve covers has the bung in the top-right corner like this one? And if so, where does yours connect, and where does the one in the second picture go?

They should connect to the block.

Let me know and I'll be able to answer your questions.






Or do you not have that provision, and is this the way things were for you from the factory?