Has no one read what I posted? This design is BAD.
"The BPV/BOV functions on differential pressure. This differential pressure is between the throttle plate. The CS FMIC adds the core and piping from the turbo to this differential pressure.
The BPV/BOV is held closed or patially closed by the small vaccume line coming from the other side of the throttle plate. as the throttle plate closes the differential pressure increases and there is less pressure on the top of the BPV/BOV holding it closed, therefore the pressure on the valve spring starts to force it open. The stock BPV opens very easily under these conditions and is in fact slightly open most of the time because the throttle is mostly below fully open.
The problem: Adding the turbo piping and core to this differential pressure means that the BPV/BOV will be open more (leaking if you will) of the time. Aftet market BPV/BOV's do work better as the passage of bypass air is not always a flat-faced valve seat ads in the Forge BPV case. With a Forge BPV for instance, this differential pressure has to be higher to bypass boost.
I believe the BCD add-on creates the illusion that boost levels are not lowered by the FMIC, but in fact, they are, so the turbo is working harder to produce higher boost to make up for the lost boost through the BPV and the pressure drop through the core and piping."