It was the ISO 5011 test. I may be thinking of the efficiency portion that started at 96%
If you mean the K&N is 96% efficient, that's correct, the figures I posted from my own analysis are in the context of that. The Donaldson is 99.93% efficient, hence the difference in grams of material passed.

If you mean the K&N is 96% efficient, that's correct, the figures I posted from my own analysis are in the context of that. The Donaldson is 99.93% efficient, hence the difference in grams of material passed.
I was referring to this picture for clarity.

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I was referring to this picture for clarity.
Yup, that's the same one, the K&N is 96.8% efficient, the Donaldson (AC-Delco) is 99.93% efficient. We can see how that translates into dirty passed in the other charts from the same test.

I know it seems like a small difference in efficiency, but when you realize how much that actually means comparatively when you run the math, it's a LOT of dirt.

Wasn't that testing that is often sited done on a large diesel truck vs. a passenger car? Not sure what impact if any that would have but yes, hard to argue that they aren't less efficient than a paper filter...in fact it's not disputable. More flow for less efficiency.

Yup, that's the same one, the K&N is 96.8% efficient, the Donaldson (AC-Delco) is 99.93% efficient. We can see how that translates into dirty passed in the other charts from the same test.

I know it seems like a small difference in efficiency, but when you realize how much that actually means comparatively when you run the math, it's a LOT of dirt.
You could use something like pantyhose is a pre-filter but I did that one time and it managed to absorb some of the oil. If I was stuck having to use an oil air filter I would at least buy the pre-charger and strap a couple rubber bands around it to keep it on snug. The best suggestion would be to try to find a dry flow sport filter. If I was stuck using the oil filter I would consider lowering my oil change interval, maybe an occasional oil flush from lubegard or liquimoly, and a slightly thicker oil by either weight or by hths.

Wasn't that testing that is often sited done on a large diesel truck vs. a passenger car? Not sure what impact if any that would have but yes, hard to argue that they aren't less efficient than a paper filter...in fact it's not disputable. More flow for less efficiency.
Yes, this was done using Duramax filters.

Only way to counter is of course more surface area, which the PowerCore does provide, through its rather unique design.

Here is my stance: I have had plenty of performance cars over the years with these filters, whether a drop in or part of a cold air intake. My cars have not suffered any ill effects. I have one in my Trax right now. 80K miles. Have had the filter in for 40K. In 10K, I will clean and LIGHTLY re oil.

FWIW- My thoughts on K&N air filters, pitch it in the garbage and use a stock air filter, especially for people who live in a dusty environment. I've seen enough UOA reports here over the years to convince me a stock air filter is a better choice. Opinions vary.

Pulled the Spectre (budget K&N) out of the MGM to clean it up, was getting a little dark in areas-got it pretty clean, but the cotton was starting to launch fuzzy bits(!). Into the trash it went...

FWIW- My thoughts on K&N air filters, pitch it in the garbage and use a stock air filter, especially for people who live in a dusty environment. I've seen enough UOA reports here over the years to convince me a stock air filter is a better choice. Opinions vary.
I've always wanted to see the K&N UOAs that were bad but never have - I've seen plenty of them the other way with no discernable dust issues. I take it screaming high SiO2/insoluables in them?

I've always wanted to see the K&N UOAs that were bad but never have - I've seen plenty of them the other way with no discernable dust issues. I take it screaming high SiO2/insoluables in them?
You're here since 2022, several were posted here over the decade plus I've been around, maybe you just haven't seen one. The general consensus of our resident experts was toss them in the garbage, if you're truly concerned about good air filtration. We have a few guys that would/will call out the experts, with replies similar to yours. Now if you reside where airborne engine damaging junk isn't a concern, or landscapers aren't blowing dust and dirt all over the neighborhoods cutting lawns, go for it. Bottom line if you feel they're good, use one.

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You're here since 2022, several were posted here over the decade plus I've been around, maybe you just haven't seen one. The general consensus of our resident experts was toss them in the garbage, if you're truly concerned about good air filtration. We have a few guys that would/will call out the experts, with replies similar to yours. Now if you reside where airborne engine damaging junk isn't a concern, or landscapers aren't blowing dust and dirt all over the neighborhoods cutting lawns, go for it. Bottom line if you feel they're good, use one.
I've been here since 2009. I've searched it and haven't found them and genuinely want to see. I base my decisions on the data I collect as it's the most meaningful but always like to see other data as well and I've never seen these bad UOAs that folks always reference. I did see something in one of the K&N posts that is ongoing about UOA but it was prefaced with the filter not being seated in the box or it was egregiously dirty/not maintained if I recall. Sharing other experiences with a product isn't "calling out" someone (expert or not)...it's the point of the forum.

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I've been here since 2009. I've searched it and haven't found them and genuinely want to see. I base my decisions on the data I collect as it's the most meaningful but always like to see other data as well and I've never seen these bad UOAs that folks always reference. I did see something in one of the K&N posts that is ongoing about UOA but it was prefaced with the filter not being seated in the box or it was egregiously dirty/not maintained if I recall. Sharing other experiences with a product isn't "calling out" someone (expert or not)...it's the point of the forum.
OK, I'm not going to dig through the archives for you. Did you read what well respected @OVERKILL posted about them? Maybe you live where dust isn't an issue. I'm in NY where landscapers are constantly blowing dust and all kinds of **** around, no thanks for the K&N. A quick look at what @OVERKILL shared is enough convincing for me, even if I didn't remember the UOA reports of the past. Many of us are here to learn about what is best for their engine's longevity, OE style air filters vs. K&N take the title from what I gathered doing my homework. You think the K&N is better, stick with it.

Edit: Here's a thread that got locked, K&N LOCKED no surprise. Read another well respected member @JHZR2 comments.

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OK, I'm not going to dig through the archives for you. Did you read what well respected @OVERKILL posted about them? Maybe you live where dust isn't an issue. I'm in NY where landscapers are constantly blowing dust and all kinds of **** around, no thanks for the K&N. A quick look at what @OVERKILL shared is enough convincing for me, even if I didn't remember the UOA reports of the past. Many of us are here to learn about what is best for their engine's longevity, OE style air filters vs. K&N take the title from what I gathered doing my homework. You think the K&N is better, stick with it.

Edit: Here's a thread that got locked, K&N LOCKED no surprise. Read another well respected member @JHZR2 comments.
For some reason this discussion goes sideways each time.

1) K&N air filters do not filter as efficiently as paper/OE-style filters. This is not debateable as the data collected during real testing support it.
2) K&N air filters flow more air than paper/OE-style filters. This is not debateable as the data collected during real testing support it.

If as a car owner/driver you want to max the performance of your car (depending on your engine, power level, etc.) or prefer a re-usable filter, K&N is a choice you can make taking into account 1) above which will require you to consider the environmental (dust) conditions you operate in. Checking the intake pipe (white glove) and UOAs can aid in this.

Nobody has conclusively shown that high-flow air filters, with their lower efficiency, reduce engine life or cause mechanical issues if maintained properly/per the manufacturer's recommendations.

I have read all that I can find on this topic including from Overkill and others in my search for the Holy Grail of info on this subject. I believe even Overkill in some of our dicussions in these threads has referenced me/my car/UOAs as indicating that the conditions I operate in look "ok" w/r to the high-flow filters I use.

I don't think "K&N is better" - I think I can gain from the higher air flow in my car (2 above) and that my conditions are such that I'm not increasing wear (1 above). And that is why these posts are always locked - many don't seem to grasp this concept b/c we typically land on "throw that in the trash".

In before lock.

For some reason this discussion goes sideways each time.

1) K&N air filters do not filter as efficiently as paper/OE-style filters. This is not debateable as the data collected during real testing support it.
2) K&N air filters flow more air than paper/OE-style filters. This is not debateable as the data collected during real testing support it.

If as a car owner/driver you want to max the performance of your car (depending on your engine, power level, etc.) or prefer a re-usable filter, K&N is a choice you can make taking into account 1) above which will require you to consider the environmental (dust) conditions you operate in. Checking the intake pipe (white glove) and UOAs can aid in this.

Nobody has conclusively shown that high-flow air filters, with their lower efficiency, reduce engine life or cause mechanical issues if maintained properly/per the manufacturer's recommendations.

I have read all that I can find on this topic including from Overkill and others in my search for the Holy Grail of info on this subject. I believe even Overkill in some of our dicussions in these threads has referenced me/my car/UOAs as indicating that the conditions I operate in look "ok" w/r to the high-flow filters I use b/c we typically land on "throw that in the trash".

In before lock.

I don't think "K&N is better" - I think I can gain from the higher air flow in my car (2 above) and that my conditions are such that I'm not increasing wear (1 above). And that is why these posts are always locked - many don't seem to grasp this concept.
I agree with a few of your points, [1 and 2 in particular]. To keep it simple imo the possible gain in HP and performance increase, if any isn't worth the risk of poorer air filtration to me. @JHZR2 brought up some good points in the thread I linked to, I don't need to run one to prove his point, or why my homework pointed me away from using them. So once again we're going to have to agree to disagree.

I agree with a few of your points, [1 and 2 in particular]. To keep it simple imo the possible gain in HP and performance increase, if any isn't worth the risk of poorer air filtration to me. @JHZR2 brought up some good points in the thread I linked to, I don't need to run one to prove his point, or why my homework pointed me away from using them. So once again we're going to have to agree to disagree.
But we don't disagree - your choice makes complete sense. Your homework pointing you away is "just fine" - but my homework pointing me to using is also...."just fine"....

But we don't disagree - your choice makes complete sense. Your homework pointing you away is "just fine" - but my homework pointing me to using is also...."just fine"....
OK. Hopefully our discussion can help others make an informed decision.

OK, I'm not going to dig through the archives for you. Did you read what well respected @OVERKILL posted about them? Maybe you live where dust isn't an issue. I'm in NY where landscapers are constantly blowing dust and all kinds of **** around, no thanks for the K&N. A quick look at what @OVERKILL shared is enough convincing for me, even if I didn't remember the UOA reports of the past. Many of us are here to learn about what is best for their engine's longevity, OE style air filters vs. K&N take the title from what I gathered doing my homework. You think the K&N is better, stick with it.

Edit: Here's a thread that got locked, K&N LOCKED no surprise. Read another well respected member @JHZR2 comments.
I just quickly glanced at that thread and it looks like the Si went down from 25 to 17ppm and thr lab attributed thr Si to new seals.

The actual testing itself shown in that thread seems to focus on coarse vs fine particulate filtration; where the KN does fine in coarse but not great with fine particulates. We then have to determine at what size of particulate is harmful. An honest question of mine

I only run a KN in my mustang to gain a few HP. I would like to see actual testing done to discover any longevity issues. An AB test. I would think certain companies would have a lot to gain by doing this type of test.

OK, I'm not going to dig through the archives for you. Did you read what well respected @OVERKILL posted about them? Maybe you live where dust isn't an issue. I'm in NY where landscapers are constantly blowing dust and all kinds of **** around, no thanks for the K&N. A quick look at what @OVERKILL shared is enough convincing for me, even if I didn't remember the UOA reports of the past. Many of us are here to learn about what is best for their engine's longevity, OE style air filters vs. K&N take the title from what I gathered doing my homework. You think the K&N is better, stick with it.

Edit: Here's a thread that got locked, K&N LOCKED no surprise. Read another well respected member @JHZR2 comments.
Interesting video and results....v. similar to the results in my UOAs using one...low SiO2 etc. with K&N. Thread locked. Classic BITOG. I need to white glove my intake hose today while I have it out, I've done it before with no issues that I was concerned about. I have a new dry-flow filter in my intake...I'll post the pic.

I just quickly glanced at that thread and it looks like the Si went down from 25 to 17ppm and thr lab attributed thr Si to new seals.

The actual testing itself shown in that thread seems to focus on coarse vs fine particulate filtration; where the KN does fine in coarse but not great with fine particulates. We then have to determine at what size of particulate is harmful. An honest question of mine

I only run a KN in my mustang to gain a few HP. I would like to see actual testing done to discover any longevity issues. An AB test. I would think certain companies would have a lot to gain by doing this type of test.
The ISO testing protocol we discussed earlier in this thread uses a specific dust that's of a size that is intended to correlate with wear; to reflect harmful particles that, if they make their way into the air intake tract and beyond, will cause/accelerate wear. I'm sure Donaldson and a few of the other heavy duty filter manufacturers have data on wear relative to efficiency.

One thing to keep in mind with regards to what @TiGeo pointed out is that, like we often discuss with oil filters, there are multiple factors in play and "flow" is not a static figure for a given application.

Allow me to explain further:
Filter media at a given surface area does not have a fixed rate of flow. The type of media, structure of the media (synthetic vs cellulose vs cotton...etc) has an impact. While usually correct, it's overly simplistic to state that a K&N of the same physical dimensions as OE will absolutely flow better. Often times, the OE filter has significantly more surface area than the K&N. Why is that important?

There are a few different ways to improve the flow of a filter:
- Decrease efficiency
- Use a superior media (synthetic)
- Increase surface area

If you are able to do either of the last two, then you can avoid doing the first one.

K&N filters compromise on all of these points. Cotton gauze is a poorer filter medium than standard cellulose. It has less surface area because of the nature of the gauze. This is why it loaded up so fast in that ISO test. But, unloaded, it does flow better than typical cellulose, at the expense of these other parameters.

You may recall back when AMSOIL introduced the EaA air filters (which have since been discontinued). These were a traditional-style filter, but used a superior synthetic filter medium produced by Donaldson. This media, like with their syntec oil filter media, provided both better flow and efficiency. These were not great sellers and the line was eventually axed.

One of the most interesting twists however was the introduction of Donaldson's "PowerCore" filter design. It uses that same synthetic media, but by using a honeycomb-style structure, significantly increases surface area. So you end up with a reasonably compact filter, but with superior efficiency and flow. Also, the honeycomb design has incredible particulate holding capacity, which you can see in the test results I posted earlier in this thread. It blew all the other filters out of the water in terms of time to hit the restriction limit.

The easiest way to determine if your air filter is causing a restriction is to fit a restriction gauge. Ironically, K&N sells a low vacuum restriction gauge ideal for naturally aspirated vehicles (the ones for diesels require a much higher vacuum, due to the turbo). It's limit is 10 inches of water (vs 20-25 inches of water for the diesel ones).

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