I tried using Blackstone's particle counts about 10 years ago to compare filters. I tried very hard to hold as many variables constant as I could, considering the vehicle was a daily driver.
As hard as I tried, I could not get consistent results enough to reach any conclusions. The only thing interesting I found was that Amsoil filters came in with the worst particle counts, but I question those results, as it only happened on two filters. I actually use Amsoil filters today, as a matter of fact.
I think the only way you can use particle analysis to test oil filters is if you are in a laboratory setting, where you can hold more variables constant.
Well, all you've done is realize that life is much larger than a lab.
This is exactly why I tell folks not to put too much stock into SAE studies they see where HALT methodology is used. HALTs (highly accelerated life test) use inputs and influences that illicit a specific result, as "proof" of concept. They often tell us exactly what we want to see. They are not worthless, but they are not to be considered completely transferrable to the real world.
Filter studies often show that finer filtration matters a lot. And yet when we do UOAs from our garage, we don't see the same effects as the HALTs. Why not? Because HALTs hold a lot of variable in a consistent manner; that's good. But they also manipulate things into an unrealistic situation to embolden the results; that's bad.
Great example ... the infamous GM filter study (SAE 881825). They "proved" that finer filtration resulted in less wear, on a factor of 8x "better". But there were several key things that most folks miss by not reading the study, as well as asking some fundamental questions. Did you know, for example, that the GM filter study that just about every bypass filter maker uses in their marketing hype is based on these conditions:
- the "base" filter was 40um nominal
- the "best" filter was 7um nominal
- they dumped in fine dust to simulate contamination; 50 grams each hour for 8 hours (this is the equivalent of 570,000 miles of "normal" silica ingestion)
- they never once changed oil, in that simulated 570k miles
- they only changed filters when the dP across the media went to 20psi
- they noted that all filters eventually clogged up to a condition where 10um was essentially the blinding point
And the coup de gras? They admitted in the summary that normal field results will never show the disparity in filter performance, because UOA data is never this significant in normal use. Why? BECAUSE NO SANE PERSON RUNS AN OCI FOR FIVE-HUNDRED-SEVENTY-THOUSAND MILES !!! Because all filter essentially stopped being effective at 10um, that means to ALL particulate matter below 10um stayed in circulation for the entire 8 hours. What happened is that the filters would eventuailly blind off to around 10um; it just took the more poreous filters longer (obviously), and so more wear happens when when more stuff above 10um is in play.
But in your garage, do you only OCI once every 570k miles????? I didn't think so. Generally, if you have a decent air filter, and a decent oil filter (no matter what brand), the wear rates are not going to change much; they'll do what they do. Soot is WAY too small in moderate OCIs (out to 15k miles). Soot starts out around 4nm in size (that's nano-meters). It has to grow via amalgamation/agglomeration about 100x larger just to get to 4um !!! As long as your oil additive package is good, the anti-agglomerates are going to keep this from happening. And if your air filter is doing it's job, not much Si is getting in. Hence, no matter how good or bad your filter is, when there's not a lot of PM (particulate matter) present, it's a moot point to talk about oil filter efficiency.
Congratulations! You're one of the few BITOGers that actually understand and experienced the reality of why filter conversations are misunderstood and overblown. Once filtration is "good enough", making it "better" has no effect in the real world, because filtration is not the only factor controlling wear.
- OCI duration
- TCB formation
- additive package effect
These all affect wear. And when you cannot even control PM via your filter selection, that pretty much means it's a non-topic.
The reason you were not getting consistent results in your trials years ago is because normal life variation of your engine's duty cycles was actually larger than your input influence. In short, the normal daily wear is greater than what the filter has effective control over, for your chosen OCI duration.