I have never been a fan of them either. My point has always been that if they do indeed increase performance then they must have less filter restriction, when it comes to a drop in filter.
I also use air filter restriction gauges and I go by them.
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79/83/86/95 F-??? 6.9 4speed
94 350 4x4 SRW 7.3 factory turbo
1930 Model A Original
My wife has three of her own.
I have to agree w/ Catfish if you don't increase the surface area but you flow more cfm you have to be lowering restriction to air AND dirt don't you?
Not when you have the oil in th efilter media. Dust & dirt naturally stick to oil - take a look at your engine and tranny for all the proof you'd ever need of that! The old oil bath filters where the air "percolated" through a reservior of oil in the bottom of the air cleaner worked great. But they went away because 1) they were messy and 2) the vehicle manufacturer couldn't sell you a replacement filter element for them (remember, way back then, the auto dealer was the main source of parts).
The theory behind the way the oiled filters work, as I understand it, is that air flowing through the filter also creates a static charge on the filter element fibers - which attracts particles to them. If the fibers were dry a lot of the particles would just bounce off of them and continue along their merry way right through the filter and into the engine. BUT, since the fibers are coated with oil, the oil causes the particles to stick.
the oil is only around the perimeter of the opening in the media anything that goes through the center of if misses that oil and take a close look at the height of the filter elements between a stock motorcraft and a K&N filter on the powerstroke the stock filter has at least double the filter area , meaning closer cells and more of them
the oil is only around the perimeter of the opening in the media anything that goes through the center of if misses that oil and take a close look at the height of the filter elements between a stock motorcraft and a K&N filter on the powerstroke the stock filter has at least double the filter area , meaning closer cells and more of them
The K&N is thinner than the OEM replacement paper filters, it is also a different media type that you are using so it isn't a direct comparison. The oil should get to more than just the perimeter. I alway oil the inside of my K&N as well as the outside, and I don't wash off the old oil I just add fresh to it each year, and thus it should just soak in more and more. When I did wash mine out it took a few days during the hot summer. I washed it and let it dry completely, then let it sit out in the sun to get warm before giving it a shot of oil inside and out then let it sit in the sun for a few hours before giving it another shot inside and out and set it down on the other side so the oil can soak in going to opposite direction. But that is only once in 4 yrs, otherwise just clean the big crap out and add fresh oil to the outside annually.
The oil bath filters are far better at filtering dirt and they can be made fibers that are like straw (not dense by any means) and yet somehow they trap the dust. Honda make oil bath filters for dusty applications for their small engines. Tillers being one example. Wackers (jumping jack trench compactors) come with two prefilters which need to be oiled and installed in the correct order and then the air is piped to the paper filter which has a dry prefilter around it (oil on paper filters = clogged filter). Many times people have washed those prefilters (because they were dirty), but not re-oiled them when reinstalling them, and a few months later find that they have a dusted motor. The dry paper filters simply can't stop the dust like the oil can.
__________________ 1989 F250 4X4 SuperCab 7.3L NA (for now) 5sp 4.10 LS 1984 F250 4X4 SuperCab 6.9L ATS 093 Turbo T19 3.54 1985 F350 Flatbed 6.9L NA T19 (down)
the oil is only around the perimeter of the opening in the media anything that goes through the center of if misses that oil and take a close look at the height of the filter elements between a stock motorcraft and a K&N filter on the powerstroke the stock filter has at least double the filter area , meaning closer cells and more of them
As was stated, the media is totally different so the comparison isn't valid. Kind of like comparing a bedsheet to cheesecloth. You are thinking like there is only 1 layer of material (like a paper filter) and the "holes" between the fibers go all the way straight through it. That isn't the case.
Where the paper filter there is only 1 layer, with the polycotton gauze of the K&N there are multiple layers, and thus no direct holes all the way straight through the media. I'm also thinking you must've missed the part about the role played by static.
Air flowing through the filter media generates a static charge on the cloth fibers. The same thing actually happens with the paper filter element too. The static charge ATTRACTS the tiny dust particles and between that attractive force and the fact that the particles do not take a straight path through the media (due to the multiple layers) this causes the particles to collide with the fibers instead of passing through between them.
With a paper filter a lot of the particles collide with the fibers too - but they just bounce off the fibers and continue on their way - all the way into the engine if they are smaller than the pores in the medial. With the oiled filter they don't bounce off the fibers - the oil traps them - so a lot fewer of them get past the filter.
The K&N is a fine filter, as long as you service it very often.
The more dust you are in, the more often you need to service it.
The oil you spray on the filter element is the key.
Fresh oil and the dust sticks to the element.
Enough dust to soak up the oil, the dust goes right through.
Inspect the filter often, if the filter looks dry it needs serviced.
I don't buy the static principle, I do buy the oil principle.
As for allowing the filter to cake....you might as well run paper, there will be less restriction.
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86 F250 HD 6.9 IDI ATS turbo "not exactly" stock 4x4 T19 BW1345 3.55LS both ends D60 front, 10.25" Sterling rear, ram air, dual stacks.
I clean my filter pretty much the same as misnomer does, maybe I won't have any suprises down the road.
My first car was/is (I bought it back from the guy I sold it to when I was 19) a '52 Willys/Overland 1-ton (6,000 GVW) pick-up, it had an oil-bath air cleaner on it that I loved!
As was stated, the media is totally different so the comparison isn't valid. Kind of like comparing a bedsheet to cheesecloth. You are thinking like there is only 1 layer of material (like a paper filter) and the "holes" between the fibers go all the way straight through it. That isn't the case.
your missing the point
it has to do with the sqaure footage of the filter element
its a different media alright and there is less than half the area of a stock filter
less material with more advertised flow
the only way thats possible is through larger openings in the media
I've got the K&N cone type on my Cummins and had the K&N stock replacement on the 6.9...I have always wondered about how good or "bad" these filters really are?!!
So...I re-oil the K&N filters at least 3 to 4 times a year.....and they do sell a filter socks [for the cone type filters] if you are traveling thru some really dusty conditions.
