I'm seeing conflicting info regarding our PCV valve
 

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?

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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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.