4 key observations for me, more or less repeating what they've said but also adding a bit of context:
- So much for the expertise that told us absolutely no detonation here. However, to be fair, perhaps though that observation and conclusion was isolated to a very small subset of the total failures. I was pretty sure though that the conclusion was extrapolated across the entire scenario.
- I don't quite see how they are so certain that bearing clearance is not at all an issue. It seems pretty clear that just from fundamentals (the ones driving this thread from the beginning) that clearance and flow rate (or starvation) are related. Clearance and flow rate are directly related as viscosity and flow rate are inversely related.
- We have the missing fundamental WHY on "tight clearances". More uniform lubrication (less load in oil film), less chance of metal to metal contact and thus longer engine life. It's much more than just a quiet engine. Solid engineering fundamentals, implemented with the extra burden of very tight quality control with real results. Some vindication that BMW M engine engineering know what the heck they are doing.
- The supercharging is a total confounding factor and everyone knows, more power = less life. Although this is good information for those considering supercharging, I am much more interested in potential issues on a stock engine.