Originally Posted By: Nyogtha
Originally Posted By: ZeeOSix
Even if the manufacturer only gives one data point (ie, 65% @ 20 microns from my curve example above), then anyone knowing how filters work would realize that the filter is even higher efficiency at particles above 20 microns, just as the curves show.
Therefore, you really don't need to know the "multiple points of data" unless you were splitting hairs and focusing directly on one or two specific particle sizes for some reason.
I disagree. You focused on the Filters A&E curve in the graph you posted. That graph shows Filters B&H behave similarly to Filters A&E but at a higher efficiency than filters A&E. Filter F is also similar. Then look at the curves for all the other filters on that graph (filters C, D,& G). Completely different curves.
Extrapolating or interpolating along a small step size from a given data point or points (say from 25 microns to 20 microns with some reasonable directional guesstimation on increase or decrease)is probably OK, but 37.5% of the filters on the graph you posted do not follow the capture efficiency curves of those who showed linear behavior over a wide particle size range.
I was going to mention that in my previous posts too, that when there is a huge difference in efficiency the curves are harder to compare. Yes, there is a "family of curves" that would all reside someplace between the most efficient (Filter D) and the least efficient (Filters A & E) curves.
But keep in mind that if an oil filter is rated very high in efficiency at 99% @ 20 micorons (or at >20 microns), that it is also going to be much more efficient for particles below 20 microns than the filter that come in at say 85% @ 20 microns. Just look at the family of curves and you an instantly see that.
Once you know how oil filter efficiency vs particle size curves basically look (as I've shown with that graph), it's easy to see that when comparing two filters at the same particle size. it will instantly tell you which one is better at every particle size. To me, that's all that matters when looking for a filter that meets my efficiency requirement. Don't have to make it rocket science, because it's really not.
Therefore, I stand by my comment of:
Originally Posted By: ZeeOSix
Therefore, you really don't need to know the "multiple points of data" unless you were splitting hairs and focusing directly on one or two specific particle sizes for some reason.
Originally Posted By: Nyogtha
Personally, I'd prefer it if they all reported a standardized test efficiency from ISO 4548-12 at 10 microns. If the general consensus is particles in the 10 to 20 micron size range cause the most damage, why not report efficiency at the small end of that range instead of the large end of that range?
My reasonable guess - it's so a larger number can be reported for efficiency across a wider spectrum of media types.
I agree ... and I also agree that they use 20 or 25 microns (or even larger) so that the efficiency numbers looks good. And some of these manufacturers will simply say "99% efficient" without any particles size. "Oh, we forgot ... that was at 100 microns". Yeah, nice.
Originally Posted By: ZeeOSix
Even if the manufacturer only gives one data point (ie, 65% @ 20 microns from my curve example above), then anyone knowing how filters work would realize that the filter is even higher efficiency at particles above 20 microns, just as the curves show.
Therefore, you really don't need to know the "multiple points of data" unless you were splitting hairs and focusing directly on one or two specific particle sizes for some reason.
I disagree. You focused on the Filters A&E curve in the graph you posted. That graph shows Filters B&H behave similarly to Filters A&E but at a higher efficiency than filters A&E. Filter F is also similar. Then look at the curves for all the other filters on that graph (filters C, D,& G). Completely different curves.
Extrapolating or interpolating along a small step size from a given data point or points (say from 25 microns to 20 microns with some reasonable directional guesstimation on increase or decrease)is probably OK, but 37.5% of the filters on the graph you posted do not follow the capture efficiency curves of those who showed linear behavior over a wide particle size range.
I was going to mention that in my previous posts too, that when there is a huge difference in efficiency the curves are harder to compare. Yes, there is a "family of curves" that would all reside someplace between the most efficient (Filter D) and the least efficient (Filters A & E) curves.
But keep in mind that if an oil filter is rated very high in efficiency at 99% @ 20 micorons (or at >20 microns), that it is also going to be much more efficient for particles below 20 microns than the filter that come in at say 85% @ 20 microns. Just look at the family of curves and you an instantly see that.
Once you know how oil filter efficiency vs particle size curves basically look (as I've shown with that graph), it's easy to see that when comparing two filters at the same particle size. it will instantly tell you which one is better at every particle size. To me, that's all that matters when looking for a filter that meets my efficiency requirement. Don't have to make it rocket science, because it's really not.

Therefore, I stand by my comment of:
Originally Posted By: ZeeOSix
Therefore, you really don't need to know the "multiple points of data" unless you were splitting hairs and focusing directly on one or two specific particle sizes for some reason.
Originally Posted By: Nyogtha
Personally, I'd prefer it if they all reported a standardized test efficiency from ISO 4548-12 at 10 microns. If the general consensus is particles in the 10 to 20 micron size range cause the most damage, why not report efficiency at the small end of that range instead of the large end of that range?

My reasonable guess - it's so a larger number can be reported for efficiency across a wider spectrum of media types.

I agree ... and I also agree that they use 20 or 25 microns (or even larger) so that the efficiency numbers looks good. And some of these manufacturers will simply say "99% efficient" without any particles size. "Oh, we forgot ... that was at 100 microns". Yeah, nice.
