PCV Valve, is known as positive crankcase ventilation valve. This is a one way device, so when car is under the boost PCV valve is not venting any crank case pressure, this is a problem. I see so many members on this forum did DIY catch can, but they all collect the oil from wrong place (not the most ideal place) There are some oil from breather but most of the by pass gas is from PCV Valve.

you ever wonder why there is not much oil in your catch can? I used to wonder the same, but after my friend suggest me to collect the by pass gas from PCV valve, my catch can fill up fast (in less than a month)

Look at HKS Shop evo CT230R, they capped the breather, and ran a hose from PCV valve to the catch can, this setup is exactly what I am doing now, in fact I didn't use a catch can, I just run a open tube to the ground, you can also run a tube from the breather to cross the open tube from PCV Valve. also read the following:
https://www.evolutionm.net/forums/sh...ight=rre+catch

 

thats crazy i didnt know that. im gonna hook up my greddy catch can soon and i do it this way and see what happens. thanx for the info

 

Use 2 catch cans one on the vent and one on the PCV connection.

 

Wow never thought of that. Got any close up pics?

 

Just get the saikou michi dual catch can setup, that's what I have and love it. Get a lot of oil from PCV and none from the other side.

 

If the HKS car is running a PCV valve, then when boosting the crankcase is sealed. Where does blowby go? If no PCV valve on the HKS car, then when boosting the turbo is pressurizing the crankcase.

They know they need to avoid either of these situations. So, I think you missed seeing some plumbing somewhere.

 

+1
As I said in our PM conversation:
All those of us with the catch tank placed between the valve cover vent and intake tube are trying to do it prevent the oil residue from going into the intake, not just catch oil wherever possible.
The PCV valve doesn't vent into the intake AFAIK, so it does not contribute to this problem. The PCV valve goes back into the crankcase and therefore is not really a problem in any way.
There is a reason the line is plumbed back into the intake. It is to prevent the crankcase and head from becoming pressurized and to create vaccuum.
As a side note, everything HKS does does to a completely built from scratch race engine that is just based off a 4G63 block is not necessarily what is best for a daily driven street car. CT230R is a far cry from a "shop car," it's a completely one-off, built from scratch race car in ever way possible, so I wouldn't go thinking that if they do it on that car, it's what you should be doing to yours or we should be doing to ours.

 

Oh yeah, and I have seen about 30X more japanese race cars use catch cans the way you say is incorrect/the way most of us do than the way you say we should instead. I'm not saying it's not good to use a catch can on the PCV, I'm just saying that it's not "wrong" as you seem to think.

 

For a while now I kept thinking why even run pcv closed systems? We could just run two breathers and let blow by gasses vent to the atmosphere. Heck most people drive without any catalytic converters when they mod their cars, how much more damage will the pcv do...

But after doing some more searching online, I foun that it is actually pretty important in ventilating under the valve cover.

http://filtercouncil.org/techdata/tsbs/94-2R1.html

So pluging that side will stop the needed ventilation.

Here is another good read:

http://www.answers.com/topic/pcv-valve

 

well like i always say if catch cans are so great then they would come stock.Thats why ill leave mine alone.

 

I added 2 catch cans. It is also important to note that you should keep the PCV valve on the ruturn line to the manifold. With the small battery, I found this to be the best place for the catch cans. Catch cans are ebay specials at $25 each. Stuffed them with SS scruber pads the catch the gunk. The engine is definitly breathing better and for some reason that I can not explain the idle is much improved. It was not bad to begin with, but now it is rock solid like stock.

 

a little blow-by never hurt anyone

 

Like EvoTech said, catching both is the best option. I went with the DC3 setup from Saikou Michi. I know you can whip up something at home like some people do, but I really liked the efficiency, look and position configuration options of this catch can. Something to consider if anyone is interesting in getting a high end catch can

 

Link to the Ebay seller please, if they are still around.

 

just some fyi on those cans, they are called greddy style when checking ebay