OEM Style v K&N / 2015 air filter study

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Don't like the intake whistle that sometimes comes with K&N style systems. I'll take OEM any day
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They seem to have used mostly diesels with 100% flow of air all the time and even under those conditions the difference in performance was negligible.
Gasoline engines only require full flow at WOT and would not benefit at all from this type of filter as filter size is greater than the engine could consume at WOT.
 
"the very high cost of K&N air filter (Rs6500/-) compared to that of the OEM air filter(Rs200/-) is a deterrent"

WOW!!

First, 200 rupees isn't that much ($3 USD)

6500 rupees = $100 !!!!
 
I'd go OE of AEM Dryflow/AFE Dry if its a performance need but never an oiled air filter. If so, pantyhose on the cone or intake plenium for safe measure.
 
Potentially worthless study, results can only be compared to same engine with same intake and doesn't consider what happens when more and more oil vapor makes its way onto intake sensors, and assumes many things as fact which are not and sometimes even gets things backwards. For example:

Quote:
Fig 8 shows that the filtering efficiency of the OEM filter was superior to that of the K&N filter. The decreased filtering efficiency of the K&N filter can be attributed to the increased pore size of the cotton gauze medium used in the filter. The actual filtering efficiency of the K&N filter will be higher in real life scenario due to the increased
surface area exposed to the air stream.


They aren't even thinking logically if they can't see that having more larger holes does nothing to increase filtering efficiency. Flow efficiency maybe, but not filtering.
 
I believe it may be a translation issue. I understand it to mean, initial filtering efficiency is is worse than what you get through daily driving, accumulating miles and thus packing the media.
 
Originally Posted By: Dave9
Potentially worthless study, results can only be compared to same engine with same intake and doesn't consider what happens when more and more oil vapor makes its way onto intake sensors, and assumes many things as fact which are not and sometimes even gets things backwards. For example:

Quote:
Fig 8 shows that the filtering efficiency of the OEM filter was superior to that of the K&N filter. The decreased filtering efficiency of the K&N filter can be attributed to the increased pore size of the cotton gauze medium used in the filter. The actual filtering efficiency of the K&N filter will be higher in real life scenario due to the increased
surface area exposed to the air stream.


They aren't even thinking logically if they can't see that having more larger holes does nothing to increase filtering efficiency. Flow efficiency maybe, but not filtering.


It seems to be a speculative assumption.

They tested the filter efficiency (defined as % cement dust retention) on a fixed area of filter material. For a given total amount of air flow (and therefore a given total amount of dust injested) with a bigger total filter area the flow rate across a unit area will be lower.

It seems a fairly reasonable assumption that filtration efficiency will increase as flow rate/unit area goes down, but it is an assumption and it should have been stated as such.
 
That "filter efficiency" procedure is apparently simple, but I'd think it would be quite difficult to standardise it in such a way as to avoid uncontrolled variables (for example, exactly how you introduce the cement powder to the airstream, over what period, and at what RH) which isn't described other than as "slowly"

I'd expect to see some measure of the variation / reproducability of that result in particlar, but also the other results, and it doesn't seem to be there.

The most accessible paper on this topic is the Oak Ridge study (Norman, Huff and West, 2009)

https://www.fueleconomy.gov/feg/pdfs/Air_Filter_Effects_02_26_2009.pdf

They don't cite that paper as such, but they cite SAE papers that share two of its authors and probably report the same data.

The effects reported in that paper are generally small to negligable, and the filter restriction threasholds were lower as well.

A Tata Sumo is of course a very different vehicle. Perhaps it has a more restricted intake path and an engine more sensitive to restriction.

Nevertheless the difference is a bit surprising, and it isn't really acknowledged in the discussion.
 
^^^^^
Very true I believe.

K&N = Chicken wire.

Good for drag strip runs. For a regular daily driver a high efficiency air filter is the way to go. Prevention beats cure in this case. As CT8 always says... The best oil filter is a very good air filter.
 
Originally Posted By: Marco620
AC Delco is 99.9! Wow! Car company is fair at best but I guess they got filtering down pat.


IF I remember correctly (and I could be wrong) that's the factory Duramax filter, which I believe was a Donaldson PowerCore.
 
Mine have been clean as a whistle for the 25 years I've had one installed, in every vehicle, except at present. UOA also came back as clean as with OEM style paper filters. I know everyone else feels differently, we'll just have to cordially disagree on this one. My personal experience and low Si UOA supersede all else.
 
A reasonable position, but it is an undisputed fact that K&N does not filter as well as:

*Factory filters
*Other high performance filters
*Other high performance filters available for a better price

K&N had their chance to dispute the above test, as well as all other claims against them, and their response was nothing but internet trolling with no technical data.

Every single independent test of K&N filters shows they are among the worst air filters for filtering efficiency.

There's literally no technical info on their side, and everything against them.

It's not my decision what someone runs in their car, but believing a K&N filter has good filtering efficiency is similar to believing the Earth is flat at this point.
 
I concede that OE style paper elements are more efficient. That's never been in question. My contention is that K&N isn't the "rock catcher" it's made out to be and is a decent filter you can use for the life of the vehicle with proper maintenance.
 
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