Originally Posted By: FZ1
. The various,filters,he used,made no difference in the WM results.
It's more about the extension of the OCI these days as opposed to improvements in WM. There are differences there too but they are really tiny in normal circumstances and hard to see. The advantages of improved filtration can come into play when you have issues with contamination rates due to problems.. such as a air filtration malfunction.
Also, WMs do increase with dirtier oil but a modern engine doesn't generate all that much. There is a threshold where contamination produces more wear but modern gas engines are so clean generally that even with a longish OCI, the oil is changed for other reasons before it reaches that higher wear threshold. If we were talking the '50s era and the transition from (boulder-catching) bypass-only filters to reasonably efficient full flows, on dirty engines that made lots of carbon, had poor ring sealing, marginal oil quality and had inefficient air filters, the decrease in wear from efficient oil filters would be much more apparent.
Most of the studies done on wear vs oil contamination and filtration recently have been done on HD diesels... which still have more "oil dirtying" tendencies and live in a tougher environment. There is more of a correlation between filter efficiency and wear in that venue.
One study from Dave Cline at Parker Filtration that showed that when bypass filtration was added to an engine and the oil was compared to the same engine without it, (IIRC) the TBN retention of the engine with the bypass filtration was higher at 15K miles than the engine without filtration was at 5K miles. Dirty oil puts a greater load on the oil's additive package and depletes it sooner than oil that stays cleaner, so it able to last longer.
As an experiment, I'm running a bypass system on my F150 and while WM were tracking per 1K intervals with other analysis on the engine at 10K, TBN was still VERY high (on a conventional MC oil BTW) and the oil's ISO cleanliness code was actually better than the new oil (which was also tested). Oxidation and nitration levels were also very low. Will be resampling at 15K.