WHAAAAT? A DOWNSIDE to K&N filters?!?!

[g.forrest]

i'm with you. all other is verbal shite.

Is the weather so bad where you guys live that we have to debate frickin' air filters?

Who cares, run whatever 'ya want. Somebody can present their position and info they have/ believe and take it or leave it! Sometimes the info is quite usefull; if you don't agree, by all means submit contradictory evidence. If you just have a bias........

How about going for a ride, instead?

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[Mal]

Its been very amusing reading this thread , long may it continue but I'm still a K&N fan but happy for anyone else to fit whatever they want.

 

I've riden massive milages (100,000 in some cases) on various big Guzzis all with K&N pods, taken the top ends/barrels apart and found no noticable wear as long as oil is changed regularly, I'm sure the original fully enclosed filters would add a few miles but not enough for me to worry about.

 

My unscientific advice is don't worry about it, just enjoy riding it whatever filter you use and a very merry Christmas & new year to one and all.

 

Mal

[mike wilson]

Ben,if you have a K&N filter,the guys who sold it to you will have filter clean and the oil that you apply after.

I only re-oil the filter every 20,000 iles or so,so dont sweat it.

 

Sling your leg over and stuff the rest works best!

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Yes, but the words "dust" and "Ireland" only occur together in sentences like:

 

"It would be dusty in Ireland if it didn't hiss down with rain all the time."

 

8-)))

 

Mine get done at about 4,000mile intervals. I use paraffin, which goes black......

 

mike

[big J]

Yes, but the words "dust" and "Ireland" only occur together in sentences like:

 

"It would be dusty in Ireland if it didn't hiss down with rain all the time."

 

8-)))

 

Mine get done at about 4,000mile intervals.  I use paraffin, which goes black......

 

mike

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[Guest Nogbad]

A dirty filter is an effective filter. As the dirt "cake" builds up, the efficiency of the filter as a barrier to finer and finer particles gets better, at the expense of pressure drop. This is the case for all filters. There are two basic conceptual designs. The "surface" element where you have a thin membrane and the cake builds up on the surface, and the "volume" element where the dirt can be trapped both on the surface and within pores in the structure of the element.

 

Pressure drop rises more quickly with a surface design and with all filters the packing density of the dust has a major effect. If the dust has a wide size range you will get a thick cake with a lower pressure drop. If the dust is fine and all one size it will clog fast. On some large scale industrial filter systems extra dust is injected in the form of crushed talc to improve the cake characteristics.

 

The filter is a separation device, it requires power as the local system entropy is decreased by organising the mixed flow into clean air and solid dust. By definition, if the filter is freer flowing and absorbs less power, the separation efficiency will be worse.

 

A "volume" element such as the polyfoam type or a good modern paper element will exhibit higher initial efficiency and a shallower d.p. gradient as the filter becomes clogged.

 

The probability is that a 20000 mile dirty K&N will be a good filter by then, but quite restrictive.

 

(here endeth the lesson)

[mike wilson]

A dirty filter is an effective filter.

 

 

(here endeth the lesson)

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I remember K&N adverts in the 1970's that proposed that the filter got better as it was used, for just this reason.

 

m

[CafeMan]

Uni Filters are best for dirtbikes/off-road vehicles where the best filtration over a longer period of time is desired. They may flow slightly less but the will flow better over extended periods. That's proven.

K&N's have been shown to flow more air resulting in the ability to gain more power. They can let in more dirt vs. a foam filter in certain environments. But regardless, one thing you have'nt mentioned is that what if you have a custom set-up. What are you going to use? Have'nt seen custom paper type pods or odd-ball shapes and sizes lately, have you? Plugged up airboxes (for epa reasons) usually don't flow very good, right. So the easiest route is to change a filter that flows better, vs. butchering the box......How about the another fact that getting a stock filter for a bike that they don't make anymore......and supplies are drying up and they are costing more and more? This scenario does exist.

 

Bottom line is that there is a trade-off. And a properly oiled and serviced K&N will function fine and give you more options for better flow and power building vs. being stuck with the stock muffled plugged up EPA mandated dB setups.

[Guest Nogbad]

If I was going to fit pods / stacks, I would use the Unifilter type.

[mike wilson]

If I was going to fit pods / stacks, I would use the Unifilter type.

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Available overthecounter anywhere in the UK?

[jrt]

Available overthecounter anywhere in the UK?

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Stop by Belfast's place. I hear he has a prescription.

 

oh, filters....sorry...nevermind.

[Greg Field]

K&Ns are the world's best butterfly strainers.

 

Hold 'em up to the light, oiled or not, and you'll see that even gnats can get through. Same for BMG and other gauze types. Keep 'em wet, or they are even worse filters. When the oil goes away, all that dirt they trapped with the oil gets sucked into your engine. I cannot tell you how many thousand gray, dry K&N pods I've seen on bikes around here. It seems the norm.

 

K&Ns are an article of faith. You either believe in them or you don't. As filters of dirt, they are inferior; as a sieve to let air in, they are superior, when clean at least. Fortunately, the air where most of us live is clean enough that we'd get by OK with no filter over the amount of miles we will ride our bikes. In such use, a K&N is OK. But why bother, for an extra 2.33 horsepower you aren't gonna use anyway?

 

If you wanna do your own test, smear a little grease on the intake tract downstream of your K&N and ride for even a few miles down a dirt road. Feel that gritty grease with your finger afterwards, and ask if you really want that grit in your engine.

 

As Jim said, K&Ns become the only choice when the filter is likely to become wet. I live in Seattle; it rains a bit here, and I get by fine with paper on my truck and most of my bikes. Paper filters do swell a little from humidity, and this can restrict flow.

[mike wilson]

As Jim said, K&Ns become the only choice when the filter is likely to become wet. I live in Seattle; it rains a bit here, and I get by fine with paper on my truck and most of my bikes. Paper filters do swell a little from humidity, and this can restrict flow.

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As I've said, I prefer easily accessible filters, whatever the make. Why not foam filters for damp-proof use?

 

m

[helicopterjim R.I.P.]

Sorry, Jim. 

 

Are you hunting me down now?

 

I reckon my posts are just to insufferably long for most people to read.  My apologies.  I don't think in sound-bytes, and I can't write that way either.

 

Knowing that there'd be some probability of egos getting wrapped around the ol' driveshaft when I opened this thread, in the spirit of "up-front full disclosure" I attempted to get all my biases and potential biases out on the table in my opening post. 

 

You'll see there and again in post #33 that I currently use a BMC re-usable air filter.  It's not a brand that I'm "married to", but it IS one of several that seem to consistently rank within a group in tests I've read where filtering capabilities on many parameters are among the best - relatively speaking.  Again - I'd be as likely to use one as the next from those that tend to consistently test within the same ranges.  I like re-usable.

 

I see by your post that BMC is acceptable to you. 

 

Are you gonna break off the hunt now?

 

I also see your implication that 45 - 67% test humidity evidently makes the entire Duramax study suspect.  That's not a dry day here and I'm on the West coast also, but not the "wet" coast.  Is there a humidity range for a filter test that you consider acceptable for producing good data?

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I don't understand what you mean by hunting you down. Its almost Christmas and I'm headed off to snow country with the family (I sort of wish I was headed to southern California though - bike weather at Christmas intrigues me).

 

I just couldn't figure out which filter you used. Checked post 33 and it didn't tell me. I use BMC too. The humidity factor is important with respect to paper filters although the test I saw (can not find it yet - still searching) shows all filters have some effect at humidities of 90% and greater. The north west coast here has humidities in the 80 to 100% range for at least half the year and I did check my paper filter on a rainy day and it felt like it was going to fall apart. I appreciate the value of a test like the Duramax test but I don't think it means that the AC Delco was the best filter. Perhaps the best under those test conditions but not a definitive result to me.

 

I hope to find the information on humidity effect on filters. It doesn't mean much to anyone in dry climates but it may help us wet coasters a lot. I'll never use another paper filter again.

 

Edit: found in your first post that you use a BMC. Who would have thought of looking there?

[Guest ratchethack]

What model BMC do you use?

 

al

Al, I checked my maintenance record, and I hadn't recorded the model number. But I trust Dave's Web site, which lists the BMC number as F45740.

 

DOUBLE EDIT: The above F4570 is FBF's part number for the BMC filter that's included in their lidless conversion kit. The BMC filter "code" number is 164/01.

 

Dave, RE: comparo tests including the BMC, sorry now that I didn't archive the tests. It was about 2 1/2 years ago. Many of the ones published on the Web seem to come and go. I spent a little time searching yesterday but couldn't find a one of 'em.

 

As I recall, the sources seemed credible and unbiased to me and relatively consistent between them. Lest anyone suspect any further bias here I didn't select studies because they had my favorite filter come out "on top". (again, I ain't got no dog in this fight.)

 

As I recall, there wasn't any single test result that made the BMC stand out from the pack in any particular measured parameter, but it was as effective or nearly as effective as the best of 'em at pulling out dirt by weight over time and by particle size, while not posing enough of a restriction on air flow that made it stand out in this regard. That's the way I remember selecting it, anyway.

 

BAA, TJM, & YMMV

[Guest ratchethack]

I don't understand what you mean by hunting you down.

I might've been getting a little paranoid...Yesterday I found myself checkin' my mirrors for the Filter Police...

 

Its almost Christmas and I'm headed off to snow country with the family (I sort of wish I was headed to southern California though - bike weather at Christmas intrigues me).

Ah, Christmas with the family in the mountains...sounds great to me! Best wishes for a blessed and SAFE holiday. Got chains, emergency stuff, food, water, snow shovel, etc.? Just checkin'...I lived at 8,000 ft. thru 5 winters. Best expect the unexpected going over the passes this time o' year...

 

I'm meeting some of the local knuckleheads for Christmas Eve breakfast and a day of local mountain riding. In addition to a few other V-11's, Gordon's bringing his newly completed concours Norton 650SS, Mitch'll be on his Black Shadow, and Larry on his V-7 Sport. It'll be a bit of a Road Geez extravaganza. Considering the Ortega Highway ride on New Year's Day too.

 

I appreciate the value of a test like the Duramax test but I don't think it means that the AC Delco was the best filter. Perhaps the best under those test conditions but not a definitive result to me.

Agreed and comments well taken. "Best" will mean different things to different riders. Hey - I reckon "the best" for many could be K&N!

 

I hope to find the information on humidity effect on filters. It doesn't mean much to anyone in dry climates but it may help us wet coasters a lot. I'll never use another paper filter again.

Thanks for your input, Jim. I'll be continuing Web searches as time permits, will advise.

 

Edit: found in your first post that you use a BMC. Who would have thought of looking there?

Only somebody who'd have any reason to expect an honest attempt at a pre-emptive bias defense, I reckon. It might've been a first...