PCV and Vacuum Issue (maybe?)


New Member
Dec 23, 2018
E92 335i
Trying to resolve an issue I left untouched for a few years now...

My current setup (pic below) uses both the Valve Cover Breather (10AN) and PCV Delete (8AN) Fittings from Vader Solutions. Stock VC and VTT Check valve (8AN).

When I first set this up and had the low side return line connected to the manifold, it would take forever just to accelerate. I can't find the picture of the codes anymore but I vividly remember needing like 3 seconds of WOT just to get from about 20 -> 40mph. I ended up just disconnecting the line and having it basically VTA.


I thought removing the high side VTA and having it go back into the rear inlet would resolve my issue but after reading a few posts and it seems like the issue may be my return line is too big. So my questions is:

Would using a 4AN line from catch can -> check valve -> manifold solve my issue?

This is what I have in mind now:

Original diagram borrowed from @Trowy88. Any insight would be appreciated. Thanks in advance!