Well, I did a bunch of oil filter research, and asked the Scott guys and then the K & P Engineering people who actually developed the filters, a bunch of questions. (
www.kandpengineering.co m)
SAE has some pretty well defined tests for oil filters, the best being J1858. This is a multi-pass test, and gives capture efficiencies at 10, 20, 30 , and 40 microns. Some conventional filters do pretty good down to the 10 micron level. Scott and K and P claim there isn't any appropriate testing, which I think the SAE would argue with.
I also downloaded a couple of very good SAE papers (952557: The influence of Filter Selection on Engine Wear, Emissions, and Performance; 95255: Correlating Engine Wear with Filter Multipass Testing), and there are clear cut, tested, and documented advantages to engine life of trapping a large percentage of particles down to the 10 micron level.
I can't get a straight answer from the Scott or K and P people on the ability of their filter to capture anything below 35 microns. It would seem to me that for the price of those things, they should have some test data to the SAE standards. If the data was any good for their filter, I'm sure they'd show it. I can only conclude that the data below 35 microns doesn't make their filter look very good.
All that said, the SAE 952557 paper makes it pretty clear that the oil filter is a secondary concern when it come to engine life. The air filter is far more critical in keeping particles out of the engine, which I guess makes sense. Engines ingest a huge amount of air, and some of the dust in the air will make into the moving bits of the engine.
A good air filter, and not changing it too often, makes the most difference to engine life. Air filters actually get better at capturing fine particles as they get clogged, so changing it too often actually hurts engine life.
Frequent oil changes are good, and a high performance oil filter that captures a large percentage of particles down to 10 microns helps.
Given that Scott and K&P won't share any information other than their 35 microns "absolute", I can only conclude their filter isn't as good as a stock paper filter below 35 microns. While running the Scott filter probably wouldn't reduce engine life to 5,000 miles, there is certainly nothing to indicate it would make your engine last longer. Most motorcyclists change their oil so often, the oil filter probably has little impact on engine life. Still, the Scott oil filter is pretty expensive for an appearance only gizmo that may not be as good for your engine as a stock paper filter.
