APR PCV Plate Tested/Evaluated
The right choice for a dedicated track car, but what about daily use?
A friend loaned me his APR PCV plate so I could test it with the crankcase pressure sensor. In a nut shell it did better than I had expected, but there are some very different “needs” of a plate system vs an OEM PCV as far as the turbo inlet pipe (vacuum source at WOT) goes. At idle - there is a tiny bit of pressure on the crankcase at basically ALL times that you’re not getting heavy into boost. Less than ideal, but better than what I thought was going to be found.
Here is some data either in the video, or derived from the data in the video to supplement it.
Summary of Findings:
OEM style PCVs (MK7/MK8) require an EXCESS of vacuum. This closes the diaphragm at about -0.9psi, and then it just has to maintain enough to remove blow-by as it is produced. This means without the Venturi, you really want to have an OEM turbo inlet pipe, though the system still isn’t perfect at all times.
PCV plates are UNREGULATED in airflow, so they breathe freely and as a result, you want to pull LOW VACUUM on them, or else you risk pulling oil suspended in air right through the entire system. The catch can doesn’t really do much of anything to help if it’s too much. Best case scenario you fill the can quickly.
The TURBO INLET PIPE is absolutely key to whatever system you have. It can be used as a TUNING TOOL to get your crankcase pressures under control. Here is a chart with the TIPs I’ve tested to get a rough idea of how they rank in order of vacuum generated:
Note: I believe the BMS draws more on a plate (about -1.0psi peak) due to the difference in restriction on the OEM MK8 PCV (Basic retrofit) vs APR plate. Explained in the video above. Remember that this is vacuum measured at the turbo inlet pipe itself - this is NOT pressure inside the crankcase. This can be used to compare relative vacuum generated by each TIP to each other, and that is about it.
