Krap&N - Real-World Example

[jeep97tj]

I also ran a K&N pod on my jeep and never had a dust problem, but very rarely did I travel behind another vehicle on a dusty gravel road. If I did I would just hand back a bit, had it on there for about 12months with no dust in the intake.

I work in a mine site and even toyota paper air filters let some dust through.

It wouldn’t surprise me if with the speed the F1 cars do and the rate they suck in air that may be they just sucked all the oil from the filter??

What is the velocity of the air travelling through the filter of a F1 car??

Road cars and F1 cars intake specs are very different.

[Jeeps]

I've got a K&N on my 4 litre petrol jeep. I've had it for about 3 years now. I think the performance gains are a load of bullshit. I don't believe that by putting a K&N filter on will give any noticeable gains.

I bought my filter purely for the fact that every 5000klm or so i can take it out, wash it, re-oil it and plonk it back and not have to buy a new filter every now and then. I've got 2 brand new paper filters in the garage ready to go in case i'm going on a LONG dusty trip but i've not yet used them in 3 years.

Now as far as oil/washable filters go, all my bikes i've ever owned (about 6 Observed Trials bikes and a few trail/enduro bikes) all used a foam washable filter. All of them. They saw some dust/dirt/mud/rain that you would never believe and they still kept on going. Sure they were 2-stroke, sure they didn't suck much air in comparison.

One more point, the main reason i bought my jeep is because of it's cast iron engine. It's a 35 year old design and will outlast most other engines and probably the rest of the jeep itself too. It's a not a fancy new fangled slow-lux, 100 series, or pootrol so it'll be able to handle a bit of rough-necking.

I'm going to keep on using my K&N.

[stuee]

When I was doing earthworks for work last year all the machines used pre-cleaners and paper elements. The air filters were blown out every 2 weeks (1 week if working with topsoil) and replaced at the service intervals. All the Cats had they're own brand filter (like every thing on the machine it seems, nuts and bolt included), where as the komatsu's and bells just had generic filters. Im sure if oiled filters offered better protection they'd use them (and blowing out filters is easier than washing and reoiling them). I was told however that blowing them out is actually a breach of ohs due to the air born dust particles. I don't use oiled filters on my car for the simple reason that the oil can be sucked through onto the afm and burn it out.

[marin]

Been told that the paper filters work by the air passing through the filter building up a charge in the paper, which in turn helps the paper filter "attract" and hold dust molecules...... anybody know the actual science of the paper filter?

marin

[jimsaq]

my air intake is absolutely spotless on the inner-side of my k&n which is impressive given the amount of crap I seem to collect on the outside of it - bees, bugs, flys, twigs and small children

if anything, from my lazy point of view it's a pain in the ass cleaning it, letting it dry and reoiling it instead of just buying a new paper filter

[playdoh]

It wouldn’t surprise me if with the speed the F1 cars do and the rate they suck in air that may be they just sucked all the oil from the filter??

This is a fair point, I know I have to have my air flow meter cleaned regularly due to filter oil residue, so the oil does get sucked in, you just have to keep the oil up to it, don't let it dry out.

As for performance gains, if your engine is tuned for the extra airflow, they can make quite a difference. I checked mine after reading this thread, no visible dust upstream.

In the really dusty stuff, something like this would take the load off the filter.
http://www.bta4wd.com/category710_1.htm

[sudso]

If anyone is interested, I would be able to make a cleanable filter that has a pressure drop near a Krap&N filter, but the efficiency of an OEM filter and still be cleanable. Would anyone be interested???

Could it be that you started this thread to promote your own potentially contemporary product? Nothing wrong with that at all but what about all the guys who might be put off oiled air filters for the wrong reasons and the ones who used them for years and had no problems will keep on using em anyway.
I'm sure in their right application they do their job, eg: high revvin performance engines away from dust etc. that need lots of air through the intake, so I think it's unfair to say as gospel that they are crap full stop.

I was put off them but not from your "personal crusade", more so from those independant test results.
I drive a lot of dusty roads so they wouldn't be a suitable application for me. Paper rules in my truck!

[quick60]

Could it be that you started this thread to promote your own potentially contemporary product?

My thoughts exactly !

p.s. I've got a K&N, which I've had for donkeys years, and no dust upstream.

[rick130]

Well the engine I was playing with was made in the US, by a company that starts with C - is that enough? They have a division that makes filters that is based in stoughton WI, the filter brand starts with F, and are used by lots of trucking companies in OZ.

that's who I thought it was, just didn't make the Fleetxxxd connection....

[j-top paj]

i checked my k&n after a weekend out on a lot of dusty roads and i was always behind somene so there was plenty of dust coming my way.
the filter had a patch of dust where the snorkel pipe comes in and thats it.
the inside was clean as new and the rest of the filter was clean too.
i brushed the dirt off and cleaned it and reoiled it and put it back in.
i will still be investing in a pre cleaner tho.
the one on my paj is still immaculate on the inside.

[sierrajim]

Could it be possible that the F1 cars blew up for some other reason than the air filters? Perhaps their head engineer made adjustments to both cars that caused the failure?

Maybe its the thousands and thousands of dollars that the teams spend on R&D went into buying porn for the Christmas party instead of testing the air filter.

I have been fitting K&N filters to vehicles for years, to date have had no issues. These are on vehicles with primary design for street use. Anyone doing a lot of dusty driving gets a paper filter with a foam pre filter that can be blown out when they fill up for fuel.

Isuzurover,

Be careful if/when you start manufacturing your own filters. Bagging someone elses product in the way you have doen in your posts here may be taken the wrong way. Doesn't bother me too much K&N filters are much the same as any other product, they are designed for a particular application, in this case its not dusty driving conditions.

[rick130]

Could it be that you started this thread to promote your own potentially contemporary product?

My thoughts exactly !

p.s. I've got a K&N, which I've had for donkeys years, and no dust upstream.

I don't believe that's Ben's motivation at all. We first discussed this on the Rover board twelve or eighteen months ago, and as Ben is a filtration engineer, I asked his opinion of Spicers test in the US. This I think is what piqued his interset in K&N and their 'marketing'.

FWIW, I used to run a K&N on the Landy as I'd had great success with them on race engines, but was concerned about it's absolute filtration levels as I drive dirt every day, so removed it after 20,000km, and that was 2 years before Spicers tests were published on the net.
When I had oil analysis done, my silicon (oxide) levels were higher with a K&N over a cellulose Donaldson, although they were still very acceptable. My 'bum dyno' couldn't detect any difference between the elements.

Ben, are you thinking of a nano-fibre media ?
Could be just the ticket for our Patrol.

[dirtyGQ]

this site has far too many einsteins who disagree with this and hate that ,i have seen that k and n filters work great. not enough air also ruins engines .

[ISUZUROVER]

Could it be that you started this thread to promote your own potentially contemporary product?

My thoughts exactly !

p.s. I've got a K&N, which I've had for donkeys years, and no dust upstream.

I don't believe that's Ben's motivation at all. We first discussed this on the Rover board twelve or eighteen months ago, and as Ben is a filtration engineer, I asked his opinion of Spicers test in the US. This I think is what piqued his interset in K&N and their 'marketing'.

FWIW, I used to run a K&N on the Landy as I'd had great success with them on race engines, but was concerned about it's absolute filtration levels as I drive dirt every day, so removed it after 20,000km, and that was 2 years before Spicers tests were published on the net.
When I had oil analysis done, my silicon (oxide) levels were higher with a K&N over a cellulose Donaldson, although they were still very acceptable. My 'bum dyno' couldn't detect any difference between the elements.

Ben, are you thinking of a nano-fibre media ?
Could be just the ticket for our Patrol.

Rick has got it in one. When I started this thread I had no intention of making air filters, it just came to me in the US-microbrewery-beer induced state of euphoria.

As Rick said above, I work in Filtration R&D. I have contact with the 3 largest filter manufacturers in the world, Donaldson, Cummins Filtration (known as Fleetguard until last tuesday) and MANN + HUMMEL (MANN FILTER).

The filters made by all these companies are excellent products, and made with filtration performance (and cost) in mind, before engine performance (though that is also an important parameter) - since these are the priorities of the engine manufacturer. Krap&N are made purely with low pressure drop (engine performance) in mind. However Krap&N have basically no R&D budget compared to these other companies, and therefore are using extremely low tech, outdated media.

The fact that so many people run Krap&N means that there is obviously a market out there for a low pressure drop filter media, however, using modern developments in fibrous media would make it possible to have a filter with a pressure drop nearly as low as a Krap&N filter, but with filtration performance near an OEM filter, and it could also be cleanable. By more modern media, I mean either polymer nanofibre media (as Rick mentioned) or patented ultrafine stainless steel fibres.

There is no guarantee it will happen and if it did it would be at least a year or two to get the R&D sorted. And I probably wouldn't bother doing it myself, rather would go through one of the companies mentioned above.

Back to the F1 car. Of course the F1 car's situation is a lot more extreme than a normal vehicle running a K&N. The maximum face velocity of the filter (engine intake flow divided by filter surface area) in the F1 car was 10 metres per second. A K&N in a normal vehicle would be lucky to reach 2 m/s. This was, however exactly the same media as used in a stock K&N, however with carbon fibre bits for all the bits that are normally made from metal or plastic. HOWEVER - the original point I was trying to make was that an OEM (paper) filter would never let particles that big through at any velocity. And the engines were both pulled down after the race, to exactly determine the source of the failure. Krap&N (understandably) got a pretty irate call from the head engineer, before they went elsewhere to buy their filters.

[ISUZUROVER]

Been told that the paper filters work by the air passing through the filter building up a charge in the paper, which in turn helps the paper filter "attract" and hold dust molecules...... anybody know the actual science of the paper filter?

marin

No. The main filtration mechanisms, diffusion, interception and inertia, are explained here:
http://www.tsi.com/AppNotes/appnotes.as ... le=iti_041

Dust particles in the air often do have an electrical charge on them. And when they are captured they impart that charge to the filter, by a process called "image charging". But that means that over time, your filter ends up with the same charge as the particles, which doesn't help filtration.

There are filters which are charged during the manufacturing process in order to improve filter performance, but these are filters which are only even expected to see light dust loads and which need very low pressure drops, such as HVAC (air con) filters.

Happy to explain further or answer any other questions.

[bastard]

Did you read the first post? The Krap&N was so bad that 2 F1 engines failed during one race on tarmac! The race track had some sand on the track, the sand was getting sucked in the intake and hitting the filter hard enough to penetrate the filter!!!

Ben, I'm not doubting that K&N are suspect, but I think you're getting carried away with this as an example. Now, I'm sure you'll correct me if I'm wrong (you usually do ) but don't F1 cars use ram induction? So the failure mode in this instance (sand particles punching through a filter with (effectively) 200 or 300km/h of momentum) isn't likely to be an issue with my snorkel fed Pajero breathing through a U-bend.

This also helps complete the picture for me. I couldn't understand how an F1 team could choose a filter which didn't filter adequately. I suspect they tested filtration efficiency, and were happy with the performance they were expecting over a 2 hour race - but they didn't anticipate this failure mode.

Like some others have said here, when I remove my K&N and check upstream in the intake, I'm not finding dust - unlike some others are finding. So I'm happy to keep using my K&N until you can come up with something better again.

Cheers,

Scott

x2

[ISUZUROVER]

Did you read the first post? The Krap&N was so bad that 2 F1 engines failed during one race on tarmac! The race track had some sand on the track, the sand was getting sucked in the intake and hitting the filter hard enough to penetrate the filter!!!

Ben, I'm not doubting that K&N are suspect, but I think you're getting carried away with this as an example. Now, I'm sure you'll correct me if I'm wrong (you usually do ) but don't F1 cars use ram induction? So the failure mode in this instance (sand particles punching through a filter with (effectively) 200 or 300km/h of momentum) isn't likely to be an issue with my snorkel fed Pajero breathing through a U-bend.

This also helps complete the picture for me. I couldn't understand how an F1 team could choose a filter which didn't filter adequately. I suspect they tested filtration efficiency, and were happy with the performance they were expecting over a 2 hour race - but they didn't anticipate this failure mode.

Like some others have said here, when I remove my K&N and check upstream in the intake, I'm not finding dust - unlike some others are finding. So I'm happy to keep using my K&N until you can come up with something better again.

Cheers,

Scott

x2

Scott and Bastard. As I said above, the maximum face velocity of the F1 filter was about 10m/s. This is due to the huge airflow that the engine sucks through at peak revs, and due to the fact that they wanted the filter as small and light as possible. Most other applications would only reach about a 10th of that.

At such high velocities, the particles have enough momentum that they bounce off the fibres they collide with, rather than adhere. Because of the open structure of the K&N, this meant that the particles were able to bounce all the way through the filter.

The F1 teams do not have the equipment to test filters themselves. They simply call up a filter manufacturer, tell them their requirements (and that money is no object) - and then get the filters from the supplier, along with the performence specs.

For those who mentioned oil, the oil droplets blowing off the filter and contaminating the airflow meter is only excess oil after oiling. I have tested oiled filters at velocities up to 10m/s while imaging them microscopically to see what happens to the oil. A surprising amount still stays in the filter.

As Rick said above, his oil was showing higher contaminant levels when running a K&N. Oil contaminants are the number 1 source of engine wear. Engines will fail earlier (through wear, not catastrophic failure) when running less efficient filters like K$N.

[not not]

Ive had a Finer Filter (uni filter now i think) in my 4.2t patrol for years and still to date when i pull it out for a clean and oil when i pull the dirty outer sock off the inner metal framed sock is allways spottless with nothing ever coming out of it when taped on a hard surface. ( inner part should not be oiled as quoted on original package)
$ 95.00 new
$30.00 recharge kit for 6 months
1 year = $155.00
The klms i do each week i would be changing it every 2 months
so it works out alot cheaper for me compared to a standed paper filter
Baring in mind my patrol was a RD2.8T so i retained the safari air box which uses the original engines filter which last time i remember buying one they were about 45.00 so thats $270.00 per year
So they were more expensive and i personaly dont think they worked as well?
I know this threads about K&N but a point was raised about all foam/cotton filters being inadaquate.
My view Jamie H

[ISUZUROVER]

For those of you saying "i can't see/feel any dust past my filter" or "the inside of my filter is spotless", that sort of test will only tell you if your filter has a hole or tear, it won't tell you if you have a 95% efficient filter compared to a 99% efficient filter, which is the main problem here.

I think it is important to show this image again. These are the mass based filtration efficiencies of a bunch of different filters. To the ISO standard that all filter manufacturers use. The filters on the right hand side with poor efficiency are oiled foam or oiled cotton. Significant research has found that the amount of dust getting past your air filter is directly proportional to the amount of engine and turbo wear. While it used to be though that only particles under 20 microns or so (smallest tolerance in an engine) were important, it has since been found that even 0.02 micron particles can cause significant engine wear. If your filter lets in more dust than you have more engine wear. Whether you can see the dust in the intake or not.

OK so I use a K&N 3" pod filter at the moment. What should I use instead? Keeping in mind that I don't have an air box....

Beebee - get in contact with your nearest donaldson/fleetguard/mann filter supplier and ask them what your best option is. If you don't want to run an airbox, you could simply buy a filter element, remove the plastic pre-cleaner part, and work out a way to attach it to your ducting - e.g. by welding a flange to the end of your ducting that the filter can seal against, with a captive nut in the middle, then clamping the element to the flange with a long bolt. If you fit the largest filter you can you will have the lowest pressure drop (and therefore retain the highest performance.

[South]

So if I can see black dirt and grime on the under side of my K&N and see a perfectly clean top side of my K&N and no dirt and grime in the intake then its still not working properly?

[ISUZUROVER]

So if I can see black dirt and grime on the under side of my K&N and see a perfectly clean top side of my K&N and no dirt and grime in the intake then its still not working properly?

The particles which are best at getting through filters are between about 0.3 microns and 5 microns (this size range varies with filter efficiency and filtration velocity). These particles are too big to diffuse out on the ducts after the filter, and to small to impact on the flow meter or at the bends in the ducts. So you cannot see any dust past the filter because it is going straight into your engine. If you can see dust after the filter or on the back of the filter then the filter is really bad. I can show you filters that remove only 80% of particles by mass but have no visible particles on the back of the filter.

[playdoh]

can't delete the double post?

[playdoh]

I think the problem is that the oiled gauze style filters (K&N, Airaid, TRD, etc) were meant for race engines that are rebuilt more often than ours are serviced, with maximum airflow and minimum required filtration, they were never meant to be a long term option.

That said, my K&N will stay in the airbox as long as I own the car, because it makes a noticable difference. weigh it up for yourself, to each thier own.

[rick130]

I can show you filters that remove only 80% of particles by mass but have no visible particles on the back of the filter.

most of the media I use in commercial air con falls into this category, and we try to limit face velocity to around th 2-2.5 m/s mark. It looks clean on the upstream side, but after the system has been there for 5-10 years or so, you should see the crap that has precipitated out.

[quick60]

Ok, who is "testand", are they a valid company ?
And who are these two blokes who did those tests ?
Give me some proof and validity of this report on the web, and I might start to believe it. It almost reads as a direct attack on K&N.

40 microns is the lower limits of visibility, so, no, you wouldn't really see anything inside an airduct if it were new, but as rick130 mentions, overtime you will see it. Wipe it out with a clean white rag and it will be visible. Now I don't see how 0.2 micron dust will give any engine wear considering that the engine oil filters are only good for about 20-25 microns, and the oil film is about 10 microns. Now I'm all woried about the soot floating around in my oil, thats got to be at least 2 or 3 microns, imagine that hanging around the insides of the cylinders

Having said all that, if you can make a filter that flows better than anything out there, and filters better than anything, you should go and see your bank manager, fund it, and get into production. I'm sure you'll make lots of money, because I'll buy one.

[bastard]

Lifes to short to worry about a bloody air filter,if the engines life expectancy is shortened this only means that the time is coming nearer for something bigger and more powerfull,when you look at it that way its not so bad i reckon delete this topic.

[ISUZUROVER]

Ok, who is "testand", are they a valid company ?
And who are these two blokes who did those tests ?
Give me some proof and validity of this report on the web, and I might start to believe it. It almost reads as a direct attack on K&N.

40 microns is the lower limits of visibility, so, no, you wouldn't really see anything inside an airduct if it were new, but as rick130 mentions, overtime you will see it. Wipe it out with a clean white rag and it will be visible. Now I don't see how 0.2 micron dust will give any engine wear considering that the engine oil filters are only good for about 20-25 microns, and the oil film is about 10 microns. Now I'm all woried about the soot floating around in my oil, thats got to be at least 2 or 3 microns, imagine that hanging around the insides of the cylinders

Having said all that, if you can make a filter that flows better than anything out there, and filters better than anything, you should go and see your bank manager, fund it, and get into production. I'm sure you'll make lots of money, because I'll buy one.

Testand Corporation
Established: 1979
Mr. Kenneth Tumidajski
99 Beverage Hill Avenue
Pawtucket, RI 02860 6214
Phone: 401-724-0306 Fax: 401-724-9320
NAICS: 334513 EMP: 10
Oil, fuel & air filter testing equipment,
paper media test equipment. Fiber optic
cabling machines.

AFAIK the guy who wanted to do the tests was just a duramax owner who wanted to know which filter was best for his truck and doubted the claims of K&N. The other guy owns the company above. Neither work for a competitor of K&N so have no obvious bias against the company. I have seen similar tests done by a number of companies which show similar results, but I am not able to publish them here.

Actually the human eye can easily see to 20 or 30 microns. Over a long time you might get some dust on the airflow meter in a petrol, but you wouldn't expect to get much if anything on the walls of the duct.

Modern oil filters are capable of much better than 25 microns, many are filtering at near 100% efficiency down to 5 microns. Filter companies are also now developing oil bypass centrifuges which can remove down to 0.02 microns (not 0.2 microns) - basically remove the soot particles. they have found that even soot can cause engine wear, and that by keeping the oil cleaner you can extend oil change intervals and reduce wear at the same time.

[quick60]

Modern oil filters are capable of much better than 25 microns, many are filtering at near 100% efficiency down to 5 microns.

Ben, yes bypass filters will do that, but not the standard full flow ones we use on our "little" engines, they would soon clog and bypass completely. I looked at a bypass filter for my engine, but it would filter out all the molybdenum from the oil, voiding the use of such a good oil in the first place. We can too carried away with filtering.

[fnqcairns]

yes bypass filters will do that, but not the standard full flow ones we use on our "little" engines, they would soon clog and bypass completely. I looked at a bypass filter for my engine, but it would filter out all the molybdenum from the oil, voiding the use of such a good oil in the first place. We can too carried away with filtering.

Hi mate who told you that? True once upon a time when molly in engine oil was more or less a particulate although today it is dissolved in solution.
You could burn it away etc but filtering by automotive bypass filters will not do it. Dont think any oil company would add the old physical form of molly to their motor oils (not grease).

Go out and get your bypass they advantage no-one but the equipment owner. Cannot say that about oiled air filters I believe. he he.

cheers fnq

[Shadow]

yes bypass filters will do that, but not the standard full flow ones we use on our "little" engines, they would soon clog and bypass completely. I looked at a bypass filter for my engine, but it would filter out all the molybdenum from the oil, voiding the use of such a good oil in the first place. We can too carried away with filtering.

Hi mate who told you that? True once upon a time when molly in engine oil was more or less a particulate although today it is dissolved in solution.
You could burn it away etc but filtering by automotive bypass filters will not do it. Dont think any oil company would add the old physical form of molly to their motor oils (not grease).

Go out and get your bypass they advantage no-one but the equipment owner. Cannot say that about oiled air filters I believe. he he.

cheers fnq

Molybdenum disulfide has a crystal structure and therfore has to be a emulsion.

The particle size used is commonly around the 1-10micron im told, so yes a bypass filter could still filter it out. (a good bypass filter)

Perhaps previously they used a larger particle size, but it still has to be a particle, its melting point is something like 1100 degrees!

And whats the old physical form of molly? do you think molly grease is 100% molly disulfide? a tub of grease woulkd cost about $5K! Or more probably! Even moly grease is just grease with moly particles through it.