There's a check valve where the PCV piping runs to the intake plenum/throttle body. As long as that's in tact you do not need a check valve on the pre-turbo connection. It's better that way anyway as you really don't want the catchcan pressurizing everytme you boost. The diagram you've got there isn't the best way to set it up. The vacuum at the accordion tube is lower and less consistent than at the plenum. I would run the PCV hardpipe into the catchcan and then T the line and route the hoses back to both stock locations.
__________________
If something breaks or you need to contact a member of the administration please post HERE. Unless it's a private or administration matter please post it on the forum. It benefits no one else if car related questions aren't posted for future users and takes away from the time I'm able to spend helping on the rest of the forum.
If you're so inclined I'm always more than happy to accept tips via PayPal. 
Tip Jar ---> 
|