In answering another thread I was thinking on something. I'm sure all of us here have heard of using oil flow restrictors in mechanical valvetrain engines of other makes ie. chevrolet race engines.
Since there are mechanical VW's could a high RPM VW engine benefit from a restrictor in the head to keep more oil flow to the main/rod/IM bearings in a high load/heat/RPM application ie. a really tuned out 1.6td? I imagine the required oil flow for a mech. VW head is really low as many old mech. VW's have or have had very poor oil pressure/flow due to badly worn IM shaft bearings that have been run for a long time and no damage to the valvetrain usually results. It may be a way to keep that high cold start oil pressure after it warms up, actually, why is it that it drops like that? I know that all VAG engines do it but why, it has to be something as other brands only drop a little pressure as they warm up.
I am just curious and since it is not widely used and documented, it is probably of little consequence.