# Oil bath air filter



## preach it (Aug 9, 2008)

The Vermeer stump grinder that I purchased has a oil bath air filter. I changed the oil in it, cleaned the air filter out the best that I could and put in 10-30 oil in the oil bath. Is the oil bath air filter supposed to be in 10-30 oil or something else? Thanks


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## Rookie1 (Aug 9, 2008)

I think they are older,of course,before multiweight oil and just used straight viscosity oil like 30wt. I think right now it doesnt matter just use whatever oil you put in engine like you did already.I worked with "oldtimers" that swore those were the best filters ever.They didnt like paper element filters,but they sure are easier to change rather than washing out oil.


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## Brimmstone (Aug 9, 2008)

People wonder why the engines on the old cars lasted so long considering the abuse some of them had. The oil bath air cleaner was the most efficient ever made. It was discontinued due to the fact that it protected the engine so well. I've taken apart engines in jeeps to reseal them and found almost none of the wear on the valve I find in newer engines operating in a dusty environment. The oil is a dead stop to all dust, dirt, chips, and all other particulate matter. Take an old oil bath apart that has been used for a while and you'll find it has a pretty good layer of sludge down in the bottom. That sludge is all the crap that the oil stopped from getting into the engine. That is why they oil foam air filters. The oil will grab most of the smaller dust particles that can normally get through the filter.


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## Frank Boyer (Aug 9, 2008)

In the 50's when oil bath air cleaners were common cars needed rings, crank bearings, and a valve job every 25,000 miles or so. Now cars go 200-300K miles without the engine being taken Part. Oil bath air cleaners keep out the big rocks. Diesel trucks went from 100K mile engine service times to 1 million mile tear downs. Our oils were improved till the 2008 LE oils, but paper filters are much better.


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## Brimmstone (Aug 9, 2008)

Frank Boyer said:


> In the 50's when oil bath air cleaners were common cars needed rings, crank bearings, and a valve job every 25,000 miles or so. Now cars go 200-300K miles without the engine being taken Part. Oil bath air cleaners keep out the big rocks. Diesel trucks went from 100K mile engine service times to 1 million mile tear downs. Our oils were improved till the 2008 LE oils, but paper filters are much better.



I'm curious what your background in mechanics is. I've been a mechanic for over 20 years now and have worked on farm and industrial equipment for years and have been involved first hand in filtration testing to see the advantages. Pleated Paper filters do NOT filter better than an oil bath. It has been proven many times. Oil baths were phased out as a way to ease maintenance. I will say a quality paper filter works better than a washable reusable filter. All of my trucks and equipment use paper filters if they didn't have an oil bath on them. My two tractors both have their original oil bath cleaners and will always use them. 

My 1949 Jeep still has it's original oil bath is still on it's first engine and has over 300000 hours on the hour meter my grandfather installed on it. I recently pulled the head and side cover to do a valve job on the old flat head as it had never been done. I was happy to find that there was almost no characteristic wear patterns from operating in a dusty environment.


Sometimes the old tech is still the best. A good case is the 1911 colt so named for being produced in 1911 and still in production today virtually unchanged.


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## Frank Boyer (Aug 9, 2008)

I started working in service stations in 1958 and have worked in automotive since then. I have completed a 4 year apprenticeship, worked as a line mechanic, and taught auto at the vocational/CC/apprenticeship level for 32 years. I spend 1-3 weeks a year in manufacture level auto classes. I have never done research on filtration. 

My observations are based on the changing service levels needed to keep engines running over the years. Better design, better oil, and fewer dirt roads may be the difference. A factory engineer at a Ford class that I took said that "6-8 onces of dirt can ruin an engine". I firmly believe that oil bath air cleaners do not filter as well as paper filters. 

Do you have any research/documentation that shows oil bath cleaners do a better job of filtering? I am going by engine life being extended by ten times.


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## Brimmstone (Aug 9, 2008)

I'll go through my files that I brought down to Texas with me tonight if they are not there I'll have my mom looked through the filing cabinets up in Ohio. I think it was a 30 percent reduction in particulate when you switched between paper to oil bath. I didn't think it was better at first myself and was kinda shocked to see the reduction. If memory serves me how they measured the amount of dust passing through was after the different filters it hit a special filter. I can't remember the exact micron count but basically the final filter was weighed before and after the test. Out of all the test the one that gained the least weight was the oil bath. I won't even go into how bad the so called performance filters did. They did the worst of all of them. The second best was a two part filter that was a paper-oiled foam unit. I wish I could find filter foam that would fit around the filter in my diesel.


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## tomtrees58 (Aug 9, 2008)

30 sea thats it tom trees


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## Rookie1 (Aug 9, 2008)

Keep it up fellas Im enjoying this.:sword: opcorn:


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## omegajim (Aug 9, 2008)

I believe oil bath is a good, but finicky system.

drive up a steep hill, or across one (on a tractor ) and you'll see what I mean.

Current, modern oil (in the crankcase) will help an engine last a lot longer than the old days.

I also believe that air filters have only caught up to oil baths in the last decade, or so - and that's for top of the line filters.

Still amazed to this day, how long some of the old iron can keep running and the punishment it must have gone through.

but other than that, keep up the discussion. I'm going to get me a big bag of reddy pop.


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## preach it (Aug 10, 2008)

I like this discussion also, it's something that I am not real familiar with. 

I tried to clean the stainless steel mesh filter above the oil the best that I could. It had a quite a bit of mess in it, it hadn't been cleaned in a while. I didn't want to mess with it too much as the stainless steel seemed to be flaking/breaking up a little bit. Is there a replacement that can be purchased for the stainless steel filter? Thanks


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## chucknduck (Aug 10, 2008)

I don't know which filter works better, but my chipper is an old asplundh from 1969. I has a ford 391 v8, runs like a champ! It has an oil bath filter in it. I don't run it faster than 2000 rpm, that might have something to do with it.


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## omegajim (Aug 10, 2008)

an older engine will run a lot longer with modern oil.

even standard oil (slightly better than sludge, imho) is a huge improvement over anything available 30 years ago.

Further, if you step up to semi synthetic, things will work better.

Lastly, more and more, I'm coming around to synthetic.


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## tdi-rick (Aug 11, 2008)

Brimmstone said:


> People wonder why the engines on the old cars lasted so long considering the abuse some of them had. The oil bath air cleaner was the most efficient ever made. It was discontinued due to the fact that it protected the engine so well. I've taken apart engines in jeeps to reseal them and found almost none of the wear on the valve I find in newer engines operating in a dusty environment. The oil is a dead stop to all dust, dirt, chips, and all other particulate matter. Take an old oil bath apart that has been used for a while and you'll find it has a pretty good layer of sludge down in the bottom. That sludge is all the crap that the oil stopped from getting into the engine. That is why they oil foam air filters. The oil will grab most of the smaller dust particles that can normally get through the filter.



Sorry, but oil bath air cleaners are very sub standard compared to virtually any paper style element.
Oil baths work by impaction, whereby the contaminant hits the media (usually metal shavings) and falls into the oil bath which holds it.
Lots of contaminants flow past the media (lest face it, the gaps are huge) and into the engine.

Can't remember what efficiency they have, but it's pretty low.
A friend of mine who is a filtration research engineer (he has a PhD, has written peer reviewed papers and worked with the biggest filter media manufacturers in the world on R&D, including Cummins Filtration (Fleetgaurd), Mann-Hummel in Germany and Donaldson) has a pretty low opinion of them, and one of his old Land Rovers had one. He ditched it for a Donaldson. 

Generally with oil baths you used to use the same oil that went into the engine, eg. my old Tractor specced 20W-40 oil in both engine and air cleaner, so I just use a 15W-40 these days.
I'm sure a 10W-30 would be fine, it's only there to hold the dust that's dropped into the sump.


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## icthruu74 (Aug 11, 2008)

You guys are making me want to go out and check out my old Farmall...

I know is that when I got it I cleaned about 2 pounds of crud out of the air cleaner...


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## Hoosier (Aug 11, 2008)

I checked mine today on the ole Chipmore. The oil looked good and there was only a bit of material in the bottom of the pan, so I left it alone. I changed the motor oil, it really did not need it, but it was low anyway. I did find the vacuum advance pull-off had lost a screw and was falling off the distributor, no wonder it was surging at WOT. :greenchainsaw:


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## bushinspector (Sep 4, 2008)

*Going green*

Since I'm starting to go a little green, I thought is was a great way to reuse old oil that had been in the engine.!!!!!!


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## Slvrmple72 (Sep 5, 2008)

My chipper has the oil filter on it. It has the Ford straight 6 industrial engine. I have changed out the oil but was wondering what would be a good way to clean the filter media? I was thinking mineral spirits and then a good compressor blow job to clear it out after it has dried. I try to keep the engine level when working so the oil in the filter does the job, something you don't have to worry about with the paper filters.


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## Rookie1 (Sep 5, 2008)

Slvrmple72 said:


> My chipper has the oil filter on it. It has the Ford straight 6 industrial engine. I have changed out the oil but was wondering what would be a good way to clean the filter media? I was thinking mineral spirits and then a good compressor blow job to clear it out after it has dried. I try to keep the engine level when working so the oil in the filter does the job, something you don't have to worry about with the paper filters.



I think that would be fine. I used to wash them in solvent tank then blow out majority of solvent.I think if you keep oil at level marked on side of cup it is low enough for oil to slosh on eneven ground.


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## Brushwacker (Sep 5, 2008)

My farmall manual says to clean the oil bath daily. I suppose they anticipate the old days running over plowed ground and excessive dust.
Back in my childhood days my Dad had a Farmall B with a belly mower which mowed at least 1 or more lawns for about 25+ years. Through those years it run about 75% of the augers during harvest and later when unloading for market,talking farming mostly corn at roughly avg 100bu per acre farming 400 acres in the mid 70's and 2000+ in 2000. I drove that tractor like a car for transportation before I got my license. Found out how to override the govener and get near twice the speed out of it. Had pulling contest with my neighbors cub cadet ,hardly ever cleaned the oil bath and I donot ever remember it getting overhauled. The only thing I remember fixing from my use was the draw bar which became a wheelie bar and got bent. Its still being used about half as much on smaller augars and I had been using it to mow woods roads until I bought my own farmall c last year. I remember a few repairs but no motor. I wouldn't be surprised if it had been overhauled once when I was gone for an extended time but either way the engine has held up incredibly considering the hours put on it.


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## tdi-rick (Sep 10, 2011)

Brushwacker said:


> My farmall manual says to clean the oil bath daily. I suppose they anticipate the old days running over plowed ground and excessive dust.
> Back in my childhood days my Dad had a Farmall B with a belly mower which mowed at least 1 or more lawns for about 25+ years. Through those years it run about 75% of the augers during harvest and later when unloading for market,talking farming mostly corn at roughly avg 100bu per acre farming 400 acres in the mid 70's and 2000+ in 2000. I drove that tractor like a car for transportation before I got my license. Found out how to override the govener and get near twice the speed out of it. Had pulling contest with my neighbors cub cadet ,hardly ever cleaned the oil bath and I donot ever remember it getting overhauled. The only thing I remember fixing from my use was the draw bar which became a wheelie bar and got bent. Its still being used about half as much on smaller augars and I had been using it to mow woods roads until I bought my own farmall c last year. I remember a few repairs but no motor. I wouldn't be surprised if it had been overhauled once when I was gone for an extended time but either way the engine has held up incredibly considering the hours put on it.



I still haven't changed my Fiat 550's air cleaner for a paper type yet, and it's mainly used for harrowing a bloody dusty dressage arena and slashing paddocks.
Come to think of it, I haven't cleaned it out for a while either :monkey:


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## robertjinnes (Sep 10, 2011)

*Everyone is partially correct---*

Oil bath filters are the best for shear volume of dirt they will collect without plugging up. they are the poorest for the percentage of dirt that they stop.

Reasoning for volume is that the oil wetted horse hair or equivalent is continually having oil bubbled up onto it, replenishing a clean oil srfuace while washing the dust/dirt into the oil reservoir where the dirt settles out. Unfortunately, some air gets thru the horse hair without effectively being scrubbed of its dirt and the dirt ends up in the cylinders and ultimately in the engine oil. As long as filter oil level is maintained and dirt level doesn't close off air flow it will filter indefinately at approximately the same efficiency. The pleated paper elements filter down to micron level but they only have a small fraction of dirt capacity in comparison.

If you have an oil bath filter on a chipper, most airborn "dirt" is wood dust and fine chips. Not the worst material for an engine to inhale. The same engine on a stump grinder or farm tractor will ingest real dirt causing real damage.

This is not an advertisement but the best filters today for both dirt volume and micron level filtering are DONALDSON and similar Cyclone with outer foam filter and inner paper filter. Not cheap but quality never is.


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## chowdozer (Sep 25, 2011)

Lessons learned from Mount St Helens, May 18, 1980

State of Montana Natural Hazards Mitigation Plan November 2001

Page 5


> Transportation
> The silica-rich glass shards of ash are harder than steel, thus excessive wear of machinery can be expected. The best mitigation for this problem is to use oil bath or foam air filters where possible, rather than paper filters (Schuster, 1981). Air, oil, and gas filters should be changed frequently, as should engine oil. Brake drums will also abrade rapidly, and should be cleaned as often as possible.



I have yet to see dust as abrasive and fine as volcanic ash.


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## tdi-rick (Sep 25, 2011)

chowdozer said:


> Lessons learned from Mount St Helens, May 18, 1980
> 
> State of Montana Natural Hazards Mitigation Plan November 2001
> 
> ...



And if you talk to anyone that is involved in filtration they will tell you that a cellulose fibre (paper) filter has a level of efficiency far greater than an oil bath filter or oiled foam.

BTW, air filtration efficiency _increases_ as the filter loads, the only reason you change a filter is that the loading decreases air flow and ultimately performance.
 
One of our members is a filtration research engineer, I can direct him this way if anyone wants real expert opinion and fact.


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## chowdozer (Sep 25, 2011)

tdi-rick said:


> And if you talk to anyone that is involved in filtration they will tell you that a cellulose fibre (paper) filter has a level of efficiency far greater than an oil bath filter or oiled foam.
> 
> BTW, air filtration efficiency _increases_ as the filter loads, the only reason you change a filter is that the loading decreases air flow and ultimately performance.
> 
> One of our members is a filtration research engineer, I can direct him this way if anyone wants real expert opinion and fact.


 
And if you talk to anyone that was in the blast zone of St Helens operating equipment, they will tell you they scrapped out more equipment with paper filters than those with oil bath filters. Hence Montana's Natural Hazards Mitigation Plan suggesting oil bath air filters.

You being big on the VW's must know that the oil bath on the bug was one of the best air filters ever made. Here's a thread for you from the baja guys: TheSamba.com :: View topic - Oil Bath Air Filters For Off Road

And of course you can still buy oil bath air filters. If they are ineffective, don't you wonder why they put them on $250K+ equipment?
http://www.mann-hummel.com.sg/EN/industrialfilters/doc/HBZJIL6b4Jk.pdf Page 57.
Typical installation for a heavy dust environment would use a paper element pre-cleaner. I can guarantee under this configuration you will find the oil in the oil bath gets dirty from dust getting through the paper element.
Honda still sells engines with oil bath filters too: 
http://engines.honda.com/pdf/manuals/31ZE0601.pdf
Why would they go to the trouble if paper filters are superior and the housing is cheaper to manufacture? An aha moment! 

Of course an oil bath filter is only as good as it's maintenance.
Real world experience trumps filtration research engineers. If you don't think so, have your filtration research engineer contact Mann or Honda. I'm sure they can supply him with expert facts and opinion.


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## tdi-rick (Sep 25, 2011)

chowdozer said:


> [snip]
> Of course an oil bath filter is only as good as it's maintenance.
> Real world experience trumps filtration research engineers. If you don't think so, have your filtration research engineer contact Mann or Honda. I'm sure they can supply him with expert facts and opinion.



I've never had anything to do with VW's, there are other Tdi's in the world 

As for Mann, he's currently doing consulting work for them, and has done for Cummins/Fleetguard and Donaldson, probably the holy trinity when it comes to engine filtration.

Fact remains that oil bath filters are poor when it comes to efficiency, there are much better alternatives, but anecdote and myth trumps reality on the internet 
The toughest environment for filtration are off road equipment, eg. mining, and they all use massive paper style elements, (with some sort of pre-cleaner) although nano fibre filters are coming on-stream from the majors. 

Most issues with paper style filters usually relate to poor sealing, I've seen a number elements that don't seal well, with terrible consequences.


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## tdi-rick (Sep 25, 2011)

BTW, thanks for that Mann catalogue, I don't have that one.


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## chowdozer (Sep 26, 2011)

tdi-rick said:


> I've never had anything to do with VW's, there are other Tdi's in the world
> 
> As for Mann, he's currently doing consulting work for them, and has done for Cummins/Fleetguard and Donaldson, probably the holy trinity when it comes to engine filtration.
> 
> ...


 
yeah, so far you have only offered your opinion. Sounds like you haven't ever used an oil bath air filter either. What is your expertise? You talked to someone who works for a filter company and they told you their filters are the best? haha


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## tdi-rick (Oct 4, 2011)

Missed this, sorry.

Yes, I have an oil bath air cleaner on an old tractor. [edit] re-read post # 14  

No, Ben doesn't work for a filtration company, he does independent research, works out of one of our universities ATM (has worked in Europe and the US) and contracts to the big filtration companies.
He's also a member on here so I can ask him over if you'd like someone that really does know what he's talking about, the rest of us are just keyboard jockeys arguing on the internet.

If you are interested here's a thread on oil baths with stated efficiencies Oil Bath Air filter, The Advantages. - Page 2 - Australian Land Rover Owners 
The big advantage of an oil bath is it's holding capacity, but efficiencies are below paper and appear on par with oiled cotton gauze (K&N).

Commercial Oil-Bath:


> Laboratory tests with various types of dust show efficiencies ranging from 95.4% to 98.6%.



paper or polymer


> » Donaldson Air Filters in Donaldson Air Cleaner housings have a 99.95+% minimum overall efficiency.
> 
> » The efficiency of the filter actually improves as dust loads up on the surface of the filter; so an air filter gets better as is gets used.



and FWIW here's a thread on testing paper vs K&N's Air Filter Tests (Finally) - Australian Land Rover Owners I supplied the filters.


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## chowdozer (Oct 6, 2011)

tdi-rick said:


> Missed this, sorry.
> 
> Yes, I have an oil bath air cleaner on an old tractor. [edit] re-read post # 14
> 
> ...


 
Quoting another forum, lol. There's a real verifiable source that will hold up to scrutiny. Of course you could also read the other posts in the same thread you linked. Many other posts disagree with you.

and FWIW, K&N's stated goal is to build a high flow filter with 98% efficiency. They meet their goal. Do you have a problem with K&N filters that meet their stated goal? If you do, then you are trying to use their filter outside the usage they intended.


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## tdi-rick (Oct 7, 2011)

I give up.

There are two spec sheets in those links, one for an oil bath and one for a paper style element, and FWIW isuzurover on that forum is the filtration engineer I've been speaking of, but if you don't wish to believe it that's ok, 
I'm just trying to prevent some other poor sucker from being trapped by the 'an oil bath is better than' a paper filter' crap.


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## chowdozer (Oct 7, 2011)

tdi-rick said:


> I give up.
> 
> There are two spec sheets in those links, one for an oil bath and one for a paper style element, and FWIW isuzurover on that forum is the filtration engineer I've been speaking of, but if you don't wish to believe it that's ok,
> I'm just trying to prevent some other poor sucker from being trapped by the 'an oil bath is better than' a paper filter' crap.


 
The first link you posted didn't work. I would assume that means you never clicked it. The mistake you make is thinking that all oil bath filters are the same. They are not. Oil bath filters rely on the momentum of the particulates in the air stream and their inability to chage directions quickly. The design has a whole lot to do with how well the filter will perform and each filter is specifically designed for it's application. It is a mistake for you to cite the spec on one oil bath and think that is concrete evidence all oil bath filters are the same and inferior to a paper filter. As I have already posted, of the equipment used in the blast zone after St Helens, the equipment using paper filters suffered a higher engine failure rate than those using oil bath filters. I know you don't believe that, but the reality is real world experience wins over lab tests every time. 

I'm still interested to know, do you have a problem with K&N filters that meet their stated goal?

And FWIW, you could go tell the baja guys their real world experiences are just wrong. Tell them they are imagining things because lab tests with the guys wearing clean white coats and control all the variables in a clean room are really the final say. lol
TheSamba.com :: View topic - Oil Bath Air Filters For Off Road


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## isuzurover (Oct 10, 2011)

Hi Rick - thought my ears were burning...

Chowdozer:


> Oil bath filters rely on the momentum of the particulates in the air stream and their inability to chage directions quickly.



This quote is correct. Oil bath air cleaners use particle inertia to collect particles.

Filters on the other hand use a range of mechanisms, *in addition to* inertia. these include diffusion, interception, sieving (in rare cases) and electrostatic effects (in some cases - usually HVAC filters and cabin air filters).

So the only way an oil bath air cleaner can work as well as a fibrous filter is to increase the velocity so the inertia of even small particles is high enough to be captured.

Also, if you look at how filters work, you will find that collection efficiency is (in general) inversely proportional to fibre diameter. That is why many companies like donaldson use filters which include nano-sized fibres. Filters such as K&N which use large diameter cotton fibres can never hope to compete with a properly engineered filter using (much) finer fibres.

As a small anecdote, one of the companies I work with had an F1 team offering them vast sums of money to develop a filter for their F1 engines. They had previously been running an oiled cotton filter of a well known brand. However both their race cars had engine failure during a race in Bahrain... It was found that even sand grains were getting through the filter at WOT filtration velocities.

If you don't believe me on how filters work, feel free to have a read of Aerosol Technology (1999) by Hinds... That is the bext (air) filtration textbook.


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## chowdozer (Oct 11, 2011)

isuzurover said:


> Hi Rick - thought my ears were burning...
> 
> Chowdozer:
> 
> ...


 
I do not consider it truthful when people comment on K&N filters without reading K&N's stated goal in manufacturing filters.

K&N Air Filter Facts You Should Know end of 2nd paragraph


> Our goal is to design our air filters to achieve maximum airflow while targeting overall filtration efficiency at 98%.



So I'll ask you the same question I asked Rick. Do you have a problem with K&N meeting their stated goal?

Comparing a K&N with a filter which targets a higher efficiency is apples and oranges.

BTW, I never questioned how filters work. I thought it's intuitive.


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## isuzurover (Oct 11, 2011)

chowdozer said:


> I do not consider it truthful when people comment on K&N filters without reading K&N's stated goal in manufacturing filters.
> 
> K&N Air Filter Facts You Should Know end of 2nd paragraph
> 
> ...



Yes I have a problem with their stated goal. It means nothing. 98% measured how, by number or mass? And for what aerosol size distribution? And what test method? 

If you use a proper fibrous filter material with sufficiently fine fibres then you could get >>98% (mass-based) particle capture efficiency, and much lower pressure drop (i.e. higher airflow) than a K&N.

98% mass based efficiency is insufficient to protect an engine that is used in dusty conditions and expected to last more than a few races.

The filters I mentioned on the F1 cars did not reach 98% (mass based) efficiency at WOT. In fact the efficiency plateaued at about 80%, as the sand grains were just bouncing their way through the filter.

I would bet that most K&N filters would struggle to achieve 98% mass-based efficiency in real world applications, and they wouldn't come anywhere near 98% number-based efficiency. 

BTW - may be intuitive to you, but most people think that filters work like sieves.


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## chowdozer (Oct 12, 2011)

isuzurover said:


> Yes I have a problem with their stated goal. It means nothing. 98% measured how, by number or mass? And for what aerosol size distribution? And what test method?
> 
> If you use a proper fibrous filter material with sufficiently fine fibres then you could get >>98% (mass-based) particle capture efficiency, and much lower pressure drop (i.e. higher airflow) than a K&N.
> 
> ...


 
What standard do you test filters too? I would assume ISO 5011? Are you familiar with ISO 5011?


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## isuzurover (Oct 13, 2011)

chowdozer said:


> What standard do you test filters too? I would assume ISO 5011? Are you familiar with ISO 5011?



I am certainly familiar with ISO5011. However as K&N state on their website, there are a range of options under 5011 (e.g. ISO coarse of ISO fine test dust, etc...). I cannot see where they state the parameters they test to.

However they do state:


> *Our actual air filters when tested generally demonstrate a cumulative filtration efficiency of between 96% and 99%.*



So - overall (presumably mass-based) efficiency between 96 and 99% (probably for ISO coarse...?).

Which means that a number of K&N filters often do reach their stated goal!

Btw - re your first question. I rarely use ISO 5011 testing (or any ISO tests) as they are fairly crude methods, and I am usually involved in primary R&D, so interested in much more accurate data.


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## chowdozer (Oct 14, 2011)

Let's address the 3 problems you have stated you have with K&N filters.


isuzurover said:


> I am certainly familiar with ISO5011.


Excellent! Then you also know that K&N uses the ISO 5011 standard based on what they have written on their website, the link I already gave you.


> The testing procedure used in the past was the SAE J726 air filter test procedure established by the Society of Automotive Engineers, however this procedure was recently superseded by testing procedure ISO 5011.


1.


isuzurover said:


> Yes I have a problem with their stated goal. It means nothing. 98% measured how, by number or mass?


Since you are 'certainly' familiar with ISO 5011, then you know that Section 6 of ISO 5011 covers dry type air cleaners for automotive applications. Further, you also know that Section 6.4 covers the efficiency test. At 6.4.3.3, you weigh the filter and record it's *mass*. 6.4.3.13 you record the *mass* of the AUT (article under test) after the test. By subtracting 6.4.3.13 from 6.4.3.3, you get the total *mass* of dust accumulated on the AUT. 6.4.3.16, you calculate the material balance, ie: the total *mass* of the dust caught by the absolute filter + the increase in *mass* of the AUT, divided by the total *mass* of the dust introduced into the system. From there it is a simple matter to calculate %. From my above rough outline of the efficiency test, I presume you get the idea the efficiency test is based on *mass*? (of course you could also use the direct weighing method described in Section 6.4.4, that would be *mass* based also). _Those are the only two options ISO 5011 gives for an efficiency test_. This answers your 'problem' 1 from above. You should know this if you are at all familiar with ISO 5011.
2.


isuzurover said:


> And for what aerosol size distribution?


Your second 'problem' is even easier to resolve. K&N states the answer right on their website, (the link I already posted).


> We subject a sample of our filter designs to this test procedure using Coarse Test Dust, which includes particles ranging in size from less than 5.5 microns to 176 microns.


Since you are familiar with ISO 5011, you also know Section 5 covers test materials and conditions. 5.1.1 outlines the two different ISO grades of test dust that can be used, subject to agreement between test organization and customer obviously. And from K&N's website once again, you know that K&N chose ISO 12130-A4 dust, which not surprisingly is the standard coarse dust. This answers your 'problem' 2 from your previous post. 
3.


isuzurover said:


> And what test method?


Your 'problem' 3 is the easiest. ISO 5011 *IS* the method. The complete test is outlined for you in ISO 5011. The materials, the equipment, airflow requirements, pressure drops, the calibration of the equipment, drawings of the test setup. Everything. Heck, they even include worksheets to record your results.This answers your 'problem' 3 from above. You should know this if you are at all familiar with ISO 5011. I have my doubts.

There you are. All your concerns about K&N filters addressed. I find it disappointing you could not address them yourself, you being in the industry and all.


isuzurover said:


> Btw - re your first question. I rarely use ISO 5011 testing (or any ISO tests) as they are fairly crude methods, and I am usually involved in primary R&D, so interested in much more accurate data.


ummm, ISO 5011 _IS_ the industry standard. Industry standards are used so that any test can be duplicated anywhere in the world at any time and filtration results obtained at different times and/or locations can be directly compared. Every major manufacturer in the US tests to ISO 5011. Not even a point to argue.


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## isuzurover (Oct 14, 2011)

I noticed you missed the quote that K&N state their filters test at 96-99% So they admit that they do not meet their own stated goal of 98% (which has been your main counter argument supporting K&N from the start).

Thanks for the line that mentioned ISO coarse. I missed that. However as I stated I suspected as much.

And if you fail to see the imitations of the ISO test method then I have nothing more to add to this thread.


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## chowdozer (Oct 16, 2011)

isuzurover said:


> I noticed you missed the quote that K&N state their filters test at 96-99% So they admit that they do not meet their own stated goal of 98% (which has been your main counter argument supporting K&N from the start).



Yeah, I was wrong. I admit that. I don't take it personally.



isuzurover said:


> Thanks for the line that mentioned ISO coarse. I missed that. However as I stated I suspected as much.
> 
> And if you fail to see the imitations of the ISO test method then I have nothing more to add to this thread.


 
First, it's good that you now understand ISO 5011 is a test method. A couple posts ago you didn't know that. You're learning. Hopefully, you have also learned ISO 5011 uses mass to measure filter efficiency. I wanted to mention this again, because you ignored my previous post. All the supposed problems you named you had with K&N filters don't exist. Maybe you should start a "B" list because your "A" list failed.

Second, ISO 5011 doesn't have any imitations.


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## isuzurover (Oct 19, 2011)

isuzurover said:


> And if you fail to see the *limitations* of the ISO test method then I have nothing more to add to this thread.



Just realised I made a typo and can't edit it. I meant to type *limitations*.


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