Larger filter= lesser efficiency?
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Originally Posted By: Turk
I have for years, and will continue to, use the extended length filter on all my vehicles.
Every time.
Me too!
I have for years, and will continue to, use the extended length filter on all my vehicles.
Every time.
Me too!
Originally Posted By: another Todd
A physically smaller filter likely has a higher pressure differential across the media, which could force some particles through that might be stopped with a lower pressure differential. As the smaller filter fills up (clogs) it will be more efficient only if the bypass stays closed which is less and less likely the more it fills up.
A larger filter with the same media, would have a lower pressure differential and would be less likely to "force" contaminates through the media, will hold more contaminants before clogging, and will be less likely to have the bypass open returning dirty oil unfiltered.
I agree.
A physically smaller filter likely has a higher pressure differential across the media, which could force some particles through that might be stopped with a lower pressure differential. As the smaller filter fills up (clogs) it will be more efficient only if the bypass stays closed which is less and less likely the more it fills up.
A larger filter with the same media, would have a lower pressure differential and would be less likely to "force" contaminates through the media, will hold more contaminants before clogging, and will be less likely to have the bypass open returning dirty oil unfiltered.
I agree.
When it comes to filter efficiency ultimately what determines it is ISO 4548-12 test results/ratings, that is the industry standard. Anything else conjecture.
It's true that a filter becomes more efficient with use as the particles caught in the media add to it's efficiency. However, when the starting rate efficiency is in the 95-99%@20um then the improvement over an oci in a well maintained engine will be negligible. Engine longevity won't be significantly affected.
As for the term 'rockcatcher', I've seen that used most here in reference to the Honda A02 and Toyota Denso OEM based on their results in Amsoil's ISO test. If one looks at those results, relatively speaking easy to understand the reference.
When all said and done safe to say that larger filter does not as a rule mean less efficient.
It's true that a filter becomes more efficient with use as the particles caught in the media add to it's efficiency. However, when the starting rate efficiency is in the 95-99%@20um then the improvement over an oci in a well maintained engine will be negligible. Engine longevity won't be significantly affected.
As for the term 'rockcatcher', I've seen that used most here in reference to the Honda A02 and Toyota Denso OEM based on their results in Amsoil's ISO test. If one looks at those results, relatively speaking easy to understand the reference.
When all said and done safe to say that larger filter does not as a rule mean less efficient.
Originally Posted By: sayjac
It's true that a filter becomes more efficient with use as the particles caught in the media add to it's efficiency. However, when the starting rate efficiency is in the 95-99%@20um then the improvement over an oci in a well maintained engine will be negligible. Engine longevity won't be significantly affected.
If I'm not mistaken, I believe the efficiency rating you see listed with ISO test results is near the end of the filter's test run after is has been loaded up some during the test.
It's true that a filter becomes more efficient with use as the particles caught in the media add to it's efficiency. However, when the starting rate efficiency is in the 95-99%@20um then the improvement over an oci in a well maintained engine will be negligible. Engine longevity won't be significantly affected.
If I'm not mistaken, I believe the efficiency rating you see listed with ISO test results is near the end of the filter's test run after is has been loaded up some during the test.
My reference was not to the specifics of the ISO test methodology but rather the results which indicate and produce the ratings. So to rephrase, when a filter shows ISO ratings in the 95-99%@20um range, then imo there's going to be negligible efficiency improvement over an oci in a well maintained vehicle.
Otoh, compared to the rock catcher filters the OP referenced like the Toyota Denso oem and Honda A02 ISO tested in the 50-65%@20um then perhaps there is some notable improvement in efficiency over the oci/fci. And also perhaps one of the reasons among several why Honda recommends changing the filter every other time.
And while said ISO test is afaik purported to be a multipass test, how that procedure correlates if at all to filter loading in vehicle use, I haven't seen documented with specifics. I have seen it posted here that Purolator claims their filters are most efficient near the beginning of use. Not going to search but it's been posted several times here. And the older ISO single pass tests' tests used to measure filter efficiency seemed to show even higher efficiency ratings than the multipass tests. Going by the name that would indicate a negative or no correlation to filter loading in vehicle use.
Bottom line though, ISO 4548-12 rating is the only way to accurately determine and comparefilter efficiency.
Otoh, compared to the rock catcher filters the OP referenced like the Toyota Denso oem and Honda A02 ISO tested in the 50-65%@20um then perhaps there is some notable improvement in efficiency over the oci/fci. And also perhaps one of the reasons among several why Honda recommends changing the filter every other time.
And while said ISO test is afaik purported to be a multipass test, how that procedure correlates if at all to filter loading in vehicle use, I haven't seen documented with specifics. I have seen it posted here that Purolator claims their filters are most efficient near the beginning of use. Not going to search but it's been posted several times here. And the older ISO single pass tests' tests used to measure filter efficiency seemed to show even higher efficiency ratings than the multipass tests. Going by the name that would indicate a negative or no correlation to filter loading in vehicle use.
Bottom line though, ISO 4548-12 rating is the only way to accurately determine and comparefilter efficiency.
^^^ I went back and dug up a couple of emails I had with Purolator regarding the ISO efficiency testing. This is what the Purolator Engineer said. Looks like the ISO test efficiency rating is the average efficiency over the span of the test which is terminated when the delta-p across the filter is 8 PSI.
====== Purolator Email Text ======
The rating of a filter is the average efficiency during the life of the test. The test is terminated at a predetermined differential pressure across the element. The report writer of the equipment will print a graph which will show typically the filter starting with higher efficiency, dropping slowly and then increase efficiency in the latter part of the test – a “hockey stick” visual effect. The reporting is automatic with the test stand and cannot be adjusted externally.
The efficiency is highest at the beginning (before the media is attacked by oil and acidity) and again at the end as contamination does improve efficiency. We cannot correlate the change of efficiency to predict the change during the lifecycle on a car.
The test duration is based on filter size and termination differential. For benchmarking, we use 8 psi increase in pressure across the filter as the self-termination point.
Based on the size of the filter, media area, media design, test can run as short as 15 minutes for a small 65mm filter for over 1 day for a class 8 full flow filter.
Typically from the graphs I see, efficiency at the end of life is slightly less than a new filter.
====== Purolator Email Text ======
The rating of a filter is the average efficiency during the life of the test. The test is terminated at a predetermined differential pressure across the element. The report writer of the equipment will print a graph which will show typically the filter starting with higher efficiency, dropping slowly and then increase efficiency in the latter part of the test – a “hockey stick” visual effect. The reporting is automatic with the test stand and cannot be adjusted externally.
The efficiency is highest at the beginning (before the media is attacked by oil and acidity) and again at the end as contamination does improve efficiency. We cannot correlate the change of efficiency to predict the change during the lifecycle on a car.
The test duration is based on filter size and termination differential. For benchmarking, we use 8 psi increase in pressure across the filter as the self-termination point.
Based on the size of the filter, media area, media design, test can run as short as 15 minutes for a small 65mm filter for over 1 day for a class 8 full flow filter.
Typically from the graphs I see, efficiency at the end of life is slightly less than a new filter.
Originally Posted By: ZeeOSix
^^^ I went back and dug up a couple of emails I had with Purolator regarding the ISO efficiency testing. This is what the Purolator Engineer said. Looks like the ISO test efficiency rating is the average efficiency over the span of the test which is terminated when the delta-p across the filter is 8 PSI.
====== Purolator Email Text ======
The rating of a filter is the average efficiency during the life of the test. The test is terminated at a predetermined differential pressure across the element. The report writer of the equipment will print a graph which will show typically the filter starting with higher efficiency, dropping slowly and then increase efficiency in the latter part of the test – a “hockey stick” visual effect. The reporting is automatic with the test stand and cannot be adjusted externally.
The efficiency is highest at the beginning (before the media is attacked by oil and acidity) and again at the end as contamination does improve efficiency. We cannot correlate the change of efficiency to predict the change during the lifecycle on a car.
The test duration is based on filter size and termination differential. For benchmarking, we use 8 psi increase in pressure across the filter as the self-termination point.
Based on the size of the filter, media area, media design, test can run as short as 15 minutes for a small 65mm filter for over 1 day for a class 8 full flow filter.
Typically from the graphs I see, efficiency at the end of life is slightly less than a new filter.
Now, how interesting is that?
I've read so many posters tell newbies that a filter becomes more efficient as time goes on, yet Purolator is saying something quite different.
Perhaps you should email the engineer with some pics of torn media?
^^^ I went back and dug up a couple of emails I had with Purolator regarding the ISO efficiency testing. This is what the Purolator Engineer said. Looks like the ISO test efficiency rating is the average efficiency over the span of the test which is terminated when the delta-p across the filter is 8 PSI.
====== Purolator Email Text ======
The rating of a filter is the average efficiency during the life of the test. The test is terminated at a predetermined differential pressure across the element. The report writer of the equipment will print a graph which will show typically the filter starting with higher efficiency, dropping slowly and then increase efficiency in the latter part of the test – a “hockey stick” visual effect. The reporting is automatic with the test stand and cannot be adjusted externally.
The efficiency is highest at the beginning (before the media is attacked by oil and acidity) and again at the end as contamination does improve efficiency. We cannot correlate the change of efficiency to predict the change during the lifecycle on a car.
The test duration is based on filter size and termination differential. For benchmarking, we use 8 psi increase in pressure across the filter as the self-termination point.
Based on the size of the filter, media area, media design, test can run as short as 15 minutes for a small 65mm filter for over 1 day for a class 8 full flow filter.
Typically from the graphs I see, efficiency at the end of life is slightly less than a new filter.
Now, how interesting is that?
I've read so many posters tell newbies that a filter becomes more efficient as time goes on, yet Purolator is saying something quite different.
Perhaps you should email the engineer with some pics of torn media?
Originally Posted By: dlundblad
Originally Posted By: HerrStig
Originally Posted By: Dufus2
Some people claim a filter is more efficient after it gets a little dirty creating more restriction. I can see how this theory can correlate to a smaller filter as more efficient.
Does that mean if it is so dirty it stops flowing it's 100% efficient?
Not necessarily. I have yet to hear of something being 100% efficient.
I am willing to bet it would be most efficient towards the end of its usage as opposed to its beginning though.
But..... the usefull life of a "small" filter is shorter, is it not, for a given amount of dirty oil through it? How efficient is it when the bypass opens?
Originally Posted By: HerrStig
Originally Posted By: Dufus2
Some people claim a filter is more efficient after it gets a little dirty creating more restriction. I can see how this theory can correlate to a smaller filter as more efficient.
Does that mean if it is so dirty it stops flowing it's 100% efficient?
Not necessarily. I have yet to hear of something being 100% efficient.
I am willing to bet it would be most efficient towards the end of its usage as opposed to its beginning though.
But..... the usefull life of a "small" filter is shorter, is it not, for a given amount of dirty oil through it? How efficient is it when the bypass opens?
Last edited:
Originally Posted By: another Todd
A physically smaller filter likely has a higher pressure differential across the media, which could force some particles through that might be stopped with a lower pressure differential. As the smaller filter fills up (clogs) it will be more efficient only if the bypass stays closed which is less and less likely the more it fills up.
A larger filter with the same media, would have a lower pressure differential and would be less likely to "force" contaminates through the media, will hold more contaminants before clogging, and will be less likely to have the bypass open returning dirty oil unfiltered.
Your conclusion is basic and simple to understand, but the "smaller is better" crowd will continue to use Sophistry to push their latest agenda.
A physically smaller filter likely has a higher pressure differential across the media, which could force some particles through that might be stopped with a lower pressure differential. As the smaller filter fills up (clogs) it will be more efficient only if the bypass stays closed which is less and less likely the more it fills up.
A larger filter with the same media, would have a lower pressure differential and would be less likely to "force" contaminates through the media, will hold more contaminants before clogging, and will be less likely to have the bypass open returning dirty oil unfiltered.
Your conclusion is basic and simple to understand, but the "smaller is better" crowd will continue to use Sophistry to push their latest agenda.
If I recall, several years ago it was discussed and basically the overall efficiency starts highest at the beginning, drops over the lifespan and then improves again as it gets on the later stages of its capacity/lifespan, but does not reach the actual efficiency of the original starting point when first installed.
Originally Posted By: ltslimjim
If I recall, several years ago it was discussed and basically the overall efficiency starts highest at the beginning, drops over the lifespan and then improves again as it gets on the later stages of its capacity/lifespan, but does not reach the actual efficiency of the original starting point when first installed.
Yep, just like it was explained by Purolator Tech Dept on the previous page. He referred to it as a "hockey stick" shaped curve.
If I recall, several years ago it was discussed and basically the overall efficiency starts highest at the beginning, drops over the lifespan and then improves again as it gets on the later stages of its capacity/lifespan, but does not reach the actual efficiency of the original starting point when first installed.
Yep, just like it was explained by Purolator Tech Dept on the previous page. He referred to it as a "hockey stick" shaped curve.
Originally Posted By: ZeeOSix
Originally Posted By: ltslimjim
If I recall, several years ago it was discussed and basically the overall efficiency starts highest at the beginning, drops over the lifespan and then improves again as it gets on the later stages of its capacity/lifespan, but does not reach the actual efficiency of the original starting point when first installed.
Yep, just like it was explained by Purolator Tech Dept on the previous page. He referred to it as a "hockey stick" shaped curve.
Right, I did read that post and just wanted to infer that it was mentioned here before with some described sloping graph much like supposed hockey stick.
Originally Posted By: ltslimjim
If I recall, several years ago it was discussed and basically the overall efficiency starts highest at the beginning, drops over the lifespan and then improves again as it gets on the later stages of its capacity/lifespan, but does not reach the actual efficiency of the original starting point when first installed.
Yep, just like it was explained by Purolator Tech Dept on the previous page. He referred to it as a "hockey stick" shaped curve.
Right, I did read that post and just wanted to infer that it was mentioned here before with some described sloping graph much like supposed hockey stick.
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