I've already mounted my saikou michi split DC3, and already installed the can for the intake side. Now I have the PCV can left to install, and I have a check valve to put in with it, but I dont know where exactly to put it. In between the pcv and can, or IM and can? Also which way should it face? Flowing side facing towards the valve cover or towards the IM? And is here a good spot to put it? Like right by the valve over or right by the IM, or next to any of the barbs or the cans?

Is a check valve really required? From searches, it appears that ppl are saying that the PCV valve is already a check valve itself, so is an extra one required?

All help is greatly appreciated!

 

Bump

 

The oem PCV is already a one way check valve so you won't need a additional one. I'm not running one on my DC3 can and it works just fine. Mounted the can on the back firewall close to intake/pcv to run the hoses short as possible.


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How sure are you on the oem check valve holding boost? My lunges over powered my oem check valve and leaked. I'm pretty sure the turbo wouldnt have any trouble doing the same.

 

I would say place the check valve between the PCV and the can. If it was placed between the IM and can, and the PCV does leak as some have said, then couldn't the check valve on the IM side maybe cause the can to pressurize? I had a can between the PCV and IM before I was tuned, removed it when I was tuned. It did catch alot of crap.

 

So in between the check valve and cancv valve to really short hose, to check valve, to hose that goes to can? Which way do I face the check valve?

This almost seems like having 2 check valves right next to each other since the pcv is already a 1 way valve

 

Easy test is to use a hand bike pump w/a gauge. Remove stock pcv hose, attach pump with a piece of hose routed to your pcv, pump up to 35+ psi, and see if it leak or holds.
Mine held 40 psi just fine.

anyways, if the OP must use a additional check valve then follow this diagram. Make sure to use a low cracking pressure check valve < 2 psi to open.

 

The stock PVC valve is open when you are pulling a vacuum in the intake manifold. This allows crankcase vapors to be pulled into the intake manifold. When you are running with boost the PVC valve closes to prevent the positive boost pressure from entering the crankcase.

So if you want to install a second check valve it should be placed between the stock PVC valve and the intake manifold. If you are using a catch can install the second check valve between the catch can and the intake manifold. It should be installed so that it is open with vapors flowing from the crankcase into the intake manifold and closed with vapors flowing from the intake manifold into the crankcase.

Here is a great thread on how the stock PVC system operates:

http://www.dsmtuners.com/forums/arti...cv-system.html

Dan (drb)

 

https://www.evolutionm.net/forums/ev...re-issues.html

 

Shouldn't need a check valve if the PCV valve is working right. From the manual.

POSITIVE CRANKCASE VENTILATION SYSTEM
CHECK M1173001100232
1. Remove the positive crankcase ventilation (PCV) valve from
the rocker cover, then reconnect the PCV valve to the
vacuum supply hose.
2. With the engine idling, put your finger on the open end of the
PCV valve, and check for negative pressure (vacuum).
NOTE: At this time, the plunger in the PCV valve should
move back and forth as the open end is covered and uncov-
ered.
3. If negative pressure is not felt, clean or replace the PCV
valve. Inspect the vacuum supply hose and vacuum supply
hose port for restriction or plugged condition.
POSITIVE CRANKCASE VENTILATION VALVE
CHECK M1173001200228
1. Hold the positive crankcase ventilation (PCV) valve with the
vacuum side down. Insert a thin rod, and using light
pressure, depress the end of the PCV valve spring by 5 − 10
mm (0.2 − 0.3 inch). Release pressure on the rod to see if
the PCV valve spring will lift the rod to its original position.
2. If the rod returns quickly to its original position, the PCV
valve is OK. If the stick does not return quickly, clean or
replace the PCV valve.