Where is the crumbling of the end cap?
Filter Efficiency: when small differences aren't small
- Thread starter Hohn
- Start date
dnewton3
Staff member
Those of us on this site for a long time have seen every brand suffer the indignities of torn media, poor adhesion, sloppy construction, leaks at component joints, uneven pleats, ... at one time or another.
My perception is that there is a general negative trend in quality all around the filter industry. Too many corporate takeovers and supply chain issues to find a brand with consistent high quality. I am not willing to accept that any one brand "X" is THAT much worse than the others. I am certainly willing to acknowledge that the general trend is undesirable across the board.
My perception is that there is a general negative trend in quality all around the filter industry. Too many corporate takeovers and supply chain issues to find a brand with consistent high quality. I am not willing to accept that any one brand "X" is THAT much worse than the others. I am certainly willing to acknowledge that the general trend is undesirable across the board.
Can you please go through some of the math on these examples? Also, it would be better to use efficiency % @ xx micorns instead of Beta Ratio for those who don't know the conversion.
Keep in mind that the ISO test dust concentration used in the ISO 4548-12 test is pretty high, so intuition says that any dirty oil volume leakage past the media in the 10-15% range is going to really impact the down stream particle counts. In the ISO 4548-12 efficiency test, high accuracy particle counters are recording the particle count range in real time on both upstream and downstream of the filter. Any leakage is going to be seen on the downstream counter.
If the theory that all the highly ISO 4548-12 rated filters tested by BR (Brand Ranks) on YouTube that use a leaf spring with metal-to-metal "seal" are leaking to some degree (some shots in their videos do show ruffled leaf springs IIRC), then that leakage seems to have brought their efficiency down to the level of the Boss which doesn't use a leaf spring, and is ISO rated at 99% >46u. People who don't understand this who watch the YT videos then believe that the Boss is some high efficiency filter, when what's more likely happening is the leaky leaf springs are bringing those filter's efficiency down to the level of the Boss.
- Joined
- Oct 3, 2023
- Messages
- 854
Running a filter circuit in series to boost Beta ratings is nice but isn't there more downsides of doing this since the drawbacks would include more pressure drop.
Most industrial literature I come across regarding bulk filtration usually have multiple filters setup in a parallel circuit to boost both accumulative filtration and capacity without the potential drawbacks of series filter circuit setup...
Most industrial literature I come across regarding bulk filtration usually have multiple filters setup in a parallel circuit to boost both accumulative filtration and capacity without the potential drawbacks of series filter circuit setup...
If you don't like talking about oil filters and discussions about what filters are what, regardless of what the brand is or where they are made, then maybe this forum isn't for you. You think the oil filter forum should be divided into US, Euro and Asian filters?
- Joined
- Sep 1, 2024
- Messages
- 541
Americas and Europe are together, not separate. That way those interested in best options for their area of choice don’t have to filter out PG endorsements they aren’t interested in, or vice versa in the other forum where Americas and Europe are duking it out.If you don't like talking about oil filters and discussions about what filters are what, regardless of what the brand is or where they are made, then maybe this forum isn't for you. You think the oil filter forum should be divided into US, Euro and Asian filters?
This is how I would analyze the effect of an internal leak on the ISO efficiency. If the filter has zero dirty oil leakage, and its efficiency is 99.9% at 20 microns (Beta 1000 @20u), then 100,000 particles upstream will be 100 particles downstream. Only 0.10% got through (100% - 99.90% = 0.10%).
If there is a 15% volume leakage of the dirty upstream, then 15% of the 100,000 particles will get through to the downstream. So 15,000 particles (through the leakage) plus 100 particles (through the media) will go downstream. The effective efficiency would then drop from 99.9% to approximately 85%. So 15,100/100,000 = 15.1% got through, and that would make the filter 100% - 15.1% = 84.9% efficient.
If there is a 15% volume leakage of the dirty upstream, then 15% of the 100,000 particles will get through to the downstream. So 15,000 particles (through the leakage) plus 100 particles (through the media) will go downstream. The effective efficiency would then drop from 99.9% to approximately 85%. So 15,100/100,000 = 15.1% got through, and that would make the filter 100% - 15.1% = 84.9% efficient.
Last edited:
So in other words, you want to make the oil filter forum political instead of purely technical. Sure ... that will fly.
Most people don’t spend time in the oil filter section like we do. They don’t want to go through pages of c&p’s. They come every few years and ask what the current “best” filter is. We provide the most current technical answer. I’m sorry your not happy with the current “best”. Just wait a minute and the answer will change….
If the upstream pump is positive displacement, the effect of more restriction is to raise pressure, but flow won’t change as long as the oil pump is not in regulation/bypass. If the pump is on the regulator, the more restriction does indeed equal less flow.
Patman
Staff member
The chances of us separating the oil filter forum based on where they are made is exactly zero. You are the only person that has ever even suggested that and frankly it’s just silly.
- Joined
- Sep 1, 2024
- Messages
- 541
It was a joke. I thought that would be seen when saying an Americas and Europe oil filter section.
Based on your post below, I'm assuming you no longer wish me to go through the math?
I think you understand the math quite well. Efficiency works fine as long as you understand to focus on what the filter lets through rather than what it catches.
If I may indulge an aside:
~~~~~~~~~~~~
BEGIN SIDEBAR
I pulled a copy of J1858 because I'd never read it, but it appears that ISO 4548-12 has basically replaced it (and is effectively the same), so I pulled that also.
The first thing that jumps out at me is this:
I find this language a bit confusing. Regardless, their definition of "multipass" is basically "repeated single pass testing in a loop." Instead of getting multiple bites at the apple, the filter is having to take a bite out of a different apple every time, if I can make the analogy. The oil is injected with contaminant, passed through the filter, supercleaned, then re-injected, passed through the filter, supercleaned, etc. It's a continuous loop. But each time it's new contaminant.
I might have been the only one, but I had a different understanding of multipass that was more along the lines of "make some contaminated oil and pass it through a filter a given number of times and see how much contaminant it removed after a specified number of passes." This is grossly incorrect and I was mistaken.
The real test using repeated re-injection of contaminant is in some ways more realistic (your engine is after all always making more contaminant) but in other ways unrealistic because the re-injection rate of contaminant (10mg/L) quite high. As you might surmise from the fact that the test will push a filter into bypass in a couple hours vs thousands of miles.
Reading the standard gives me a bit of caution now in making comparisons about filters. Here's why:
1) The ISO standard seemingly uses whatever test flow rate the filter OEM asks them to use. How do you know one filter maker isn't using a wildly different flow rate than another for the same nominal filter? What if one OEM for a typical Honda spin-on says to use 3L/min and another says to use 5L/min? The test duration and injection rate are all scaled to these nominal flows which are not controlled by the standard. By my reading, there's nothing in the standard the precludes a filter manufacturer from sandbagging the test by using a lower nominal flow rate, because face velocity (flow rate per unit of media area) is a major contributor to effective filter efficiency. If you take two filters of identical media but one is twice as large as the other, the latter will have measurably superior filtration efficiency simply because the face velocity through the media is half as much.
2) The ISO standard test also uses a manufacturer-stated capacity for dust as an input to the test parameters. (with a caveat that it can be measured if this is unavailable). Again, loosely controlled at best an invites potential manipulation of test results.
I feel like this test has some weaknesses that allow it to be manipulated. I'd much rather than instead of using a flow rate provided by the filter OEM that instead the flow rate was scaled to stated media area (sq meters or inches). This would also ensure that test results scale properly with filters of different sizes.
END SIDEBAR
~~~~~~~~~~~
That said, I think the efficiency results generated by ISO 4548 might not show up much in-engine. While we all want more efficient media and cleaner oil, the difference between a 99% and 98.7% efficient filter (at a given micron size) is likely not visible because it's just another pass or two through the media in terms of cumulative efficiency.
When the contamination injection rate is low (as in a running engine) the media is going to have a lot of bites at the same apple. Think of it this way: How many passes through the media are necessary to achieve an EFFECTIVE efficiency of 99.9%? Let's assume for now that 99.9% probability is certainty, so if I achieve that level of probability a particle will be removed, I consider it to be removed.
So let's say I've got a 99% efficient filter. How many passes to hit 99.9%? Or how many passes to get 10,000 particles below 10 particles? Our first pass takes 10,000 particles down to 1000, and the second takes 1000 down to 10, so two passes.
More generally, (1-efficiency)^passes will give you cumulative efficiency. Break out the logarthims and you get something like this:
[td]
0.987
[/td][td]0.999
[/td][td]1.591
[/td][td]
0.990
[/td][td]0.999
[/td][td]1.500
[/td][td]
0.950
[/td][td]0.999
[/td][td]2.306
[/td][td]
0.900
[/td][td]0.999
[/td][td]3.000
[/td][td]
0.850
[/td][td]0.999
[/td][td]3.641
[/td]So it would seem in the real world that differences in efficiency might not matter a whole lot-- the best filters still need more than one pass to get to 99.9% probability of removal, and the lesser filters get it done by the 3rd pass.
Even a somewhat abysmal 85% single pass efficiency will still get the job done on the 4th pass.
I probably need to add a question mark to the title of the OP starting this thread, because maybe small differences in efficiency don't matter that much after all?
I doubt that ... you've brought up buying filters based on where they are made many times, so it's obvious that you have other views on how people should buy products. If you want to buy based on that, then fine ... but don't tout it in every other post you make.
- Joined
- Sep 1, 2024
- Messages
- 541
Holy mackerel as they say.
The ISO 4548-12 test is passing a per-determined viscosity of test oil contaminated with a per-determined concentration (baseline of 10 mg/L) and injection rate of ISO test dust called out in ISO 4548-12. There is a calibrated automatic particle counter both upstream and downstream of the filter that constantly measures the particle counts of the test oil in microns over a large range. This gives a real-time efficiency and how it can be seen that oil filters typically get less efficient as they load up and the dP across them increases. The test is ran until a per-determined dP above the new filter dP is reached, and that defines the over-all efficiency and the holding capacity of the filter element. This is is all discussed in the big Ascent ISO efficiency thread - LINK HERE
So in essence, the ISO 4548-12 test is like a "continuously monitored single-pass" test since the particle counters are constantly measuring the upstream and downstream particles in the test oil. Throughout the test run, every second in time could be looked at as a "single pass" efficiency. So the multi-pass test is basically many single passes occurring in succession. The definition of a "multi-pass" test in ISO 4548-12 is: "Test which requires the recalculation of unfiltered fluid through the filter element".
The ISO 4548-12 efficiency is the average over-all efficiency from of the test beginning efficiency to the test end efficiency, which will therefore include the filter's efficiency decrease as the filter loads up and the dP increases across the media. So when you see an oil filter with a high ISO 4548-12 efficiency rating, it means that the filter does very well in retaining already captured debris, and it loses little efficiency as it loads up. When Ascent did his ISO testing, the Boss for instance lost a ton of efficiency as it loaded up, and that's the main reason its overall ISO 4548-12 efficiency is so low.
I don't have the most recent copy of ISO 4548-12, so not sure what updates have been done over the years. But the copy I have says the dust contamination level baseline should be 10 mg/L and the injection rate baseline should be 0.25 L/min. That along with a suggested test duration of more than 30 minutes. Using the estimated holding capacity from the filter designer, the equations in ISO 4548/-12 are then used to determine the appropriate test flow volume through the filter. Anyone running an official ISO test lab (like Andrew at Ascent) is going to use the appropriate parameters and not going to just do what someone who doesn't understand the testing procedure is wanting -ie, if someone comes to the test lab and wants 60L/min of flow through a tiny oil flter, the test engineer is going to say that's a reduculous test and determine what the flow rate should be based on the parameters layed out in the test procedure. There is some wiggle room, but if the test lab is certified to run the test, the test engineer isn't going to do something rediculous.
When Ascent did his testing on the 6 filters (LINK HERE) all specified for the same engine, he used the same flow rate, duct concentration rate and injection rate, and the same delta dP on all of them ... so it was a good apples-to-apples comparison. If you compare the manufacturer's claimed IOS 4548-12 efficiency of all those filters (all done separately in some other labs), those claimed ISO efficiencies pretty much rank in the same order as Ascents testing ranked those filters.
Of course the difference of 99% and 98.7% won't be seen. But what has been shown in many engine wear studies is that a more efficiency oil filter results in cleaner oil, which results in less engine wear. That fact will never change. You've been a member here since July 2005, so I'm surprised you haven't seen some of these discussions and not gotten into them until now.
Remember that the ISO 4518-12 test is monitoring the filter efficiency in real time. A filter rated at 99% @ 20u is indeed that efficient on one pass since that's how the real-time upstream and downstream particle counters are measuring the real time efficiency.
A somewhat abysmal 85% efficient single pass is still letting 14% more degris past the filter than the 99% filter. And that 85% efficient filter may become even less efficient the longer it's used and the more it loads up with debris. The 99% ISO reated efficient filter isn't losing much efficiency as it loads up. Even if the level of contamination is much less in the real world, keeping the oil cleaner is benificial ... especially the longer the OCI, because engine wear from dirty oil is a funtion of the contamination level times how many trips the sump makes through the engine between OCIs.
Last edited:
Similar threads
