1.6N/A was the first 50° motor. When they offered the 1.6TD in Europe, North America got a 1.7N/A that was only used in Vanagons. 1.9N/A or TD weren't offered in Vanagons, but T4's got them.
take a look at the specifications for the Mann + Hummel "Provent 200"...it's got ~.75" I.D. fittings at the inlet and outlet so there should be very little resistance to back pressure, taking into account the intake vacuum. I'd plumb it so the cleaned fumes are routed back to the intake post-aircleaner & pre-turbo, and catch the crud (it has water in it) to drain overboard periodically. Your AWIC/intake deserves it.
The "what" is a runaway due to the engine burning its own oil as fuel. The cam baffle and hockey puck are both there to prevent that from happening. A diesel doesn't much care if it is burning engine oil or diesel fuel, it'll rev as high as the volume of fuel it receives allows. Sent from my HTC One X using Tapatalk 2