I'm seeing conflicting info regarding our PCV valve

[Jesse36m3]

From the research I've done, it appears the stock PCV was never meant to see boost obviously, so the solution on this forum is to replace it with a WRX / STI valve. Okay, that makes sense. So is that only for people not running a catch can?

According to the Velox AOS instructions (which I intend to buy) it states to remove it entirely:


2.7. Remove the PCV valve using the 19mm deep socket, extension, wobble socket, and ratchet.

2.8. Install the supplied 3/8NPT to 1/2" adapter fitting. You’ll need a 7/8” deep socket to install this. It is recommended to use some Teflon tape or sealant to ensure a leak free seal as shown below. Install this adapter to 12-18 ft-lbs.

2.13. At this point, you need to decide if you’re going to install it in an OEM type fashion (recommended for NA for simplicity) or a vacuum style install (recommended for Forced Induction installs).

2.13.1. Forced Induction Install – Blocking off intake manifold port completely, for vent to atmosphere or when both outlet ports of the AOS are going to a vacuum source.


Essentially, I just want to understand why the valve gets removed entirely?

Also, is it better to vent to atmosphere or run it to a vacuum source like the intake pipe before the compressor?

[kimcheefists]

I believe they tell you to remove the valve because our PCV valve wasn’t designed to withstand pressure going into the crankcase. When I had the JRSC, I installed their supplied check valve inline before the AOS (between AOS and intake manifold) to prevent pressurizing the AOS and crankcase when under boost


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[xwd]

Does the AOS itself act as a way to block the crankcase from being pressurized? NA I don't know if it matters a lot whether the PCV is there or not, but not sure exactly why they would just replace it. The other AOS systems out there do not replace the PCV valve.