While I'm new to the flat six and it's problems I've spent a lot of time
thinking about the oiling problems with the 928/ 944 platform. In that camp more and more people seem to understand that aeration is an major factor. Some run Valvoline racing oil because of it's anti foaming properties, but there is no conclusive data that this is enough.
The 928 engine has problems with oil collecting in the cylinder heads. Enough oil is trapped there to possibly uncover the pickup, at least momentarily. This has been conclusively proven using modified valve covers with plexiglass windows, cameras and strobe lights. The same problem is occurring with the m96 where oil pools in the front of one bank during breaking and in the rear of the other during acceleration. I believe this is why some think it is important to remove resistance to the oil returns to the sump. However, the oil is
pumped back by the scavenge pumps, so the swirl pots should not really slow down the return.
I believe a major part of the problem, and one which Porsche knew about and addressed with
the dual stage scavenge pumps, is the oil pooling in the head when it is desperately needed in the sump. Then, when the car changes state a big volume of highly aereated oil is returned by the scavenging pump. This is dumped into a small volume of oil in the sump and this leaves little to no time for the entrapped air to escape before the oil is sucked up by the pickup and delivered to the bearings. Usually during heavy acceleration when a high pressure oil film is needed the most.
Keep in mind that I have no way of proving this, it is only my current theory. What actually goes on i a dynamic situation is anybody's guess, but shock waves may form, and the oil will be splashing around a lot. The volume of oil moved by the pump is staggering.
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