Independant Foam vs Cotton air filter test.

[K2-]

I'm looking to upgrade my OEM air filter. In the past I've always used K&N on every motorcycle and car I've owned. Being in the engineering field however I couldn't resist the urge to research what's new on the market. Trusting reviewers "seat of the pants" opinions is not very technical and lead to a search for unbiased laboratory testing results. I found a very good test some of you might be curious to read.


The Great Air Filter Shootout (http://ducatigarage.netfirms.com/filtertest.html)

[Heavy]

Funny, I figured that it was going to be one of those use-a-K&N-filter-and-your-motor-is-junk-in-20,000-miles stories.

[greywolf]

I would like to see a test on how much dirt gets through a new K&N filter. Even K&N says it filters better after it captures some dirt. I ran them on previous bikes and never had an engine problem though.

[Big B]

I'd probably run a K&N where I live, but not if I lived where it could be sandy. The stock filters are actually pretty darn good, I haven't found a good enough reason to switch yet. ;)

[Monterey10]

I read a test that showed that the K&N had better airflow than stock until the filters got a little dirty. The stock filter worked OK and the K&N worked worse. So, the message is, you need to keep the K&N clean to have an advantage. Let it get dirty and you'll be at a disadvantage. If your bike is running lean now, it may run very lean with a K&N filter installed.

There is a process for cleaning and re oiling the K&N. I always seem to over oil the K&N and get sticky red oil everywhere. You might let them sit in a plastic bag for a day before installing.

With the K&N you get more intake noise, which is cool if you want more noise.

Regarding air filters in general, pay attention to the O ring around the filter. People have had dirt leak around the filter into the air box. The old timey fix for this was to put a little grease on the O ring to catch the dirt.

[rcacs]

I'm looking to upgrade my OEM air filter. In the past I've always used K&N on every motorcycle and car I've owned. Being in the engineering field however I couldn't resist the urge to research what's new on the market. Trusting reviewers "seat of the pants" opinions is not very technical and lead to a search for unbiased laboratory testing results. I found a very good test some of you might be curious to read.


The Great Air Filter Shootout (http://ducatigarage.netfirms.com/filtertest.html)

Thanks, thats an interesting read.

Cheers!

[Jimding]

Very much appreciate the article. Would have been nice to see the distribution of sizes of dirt particles being used, and the sizes that went through the filters, along with a time profile of changes (yeah, I'm a science geek). Foam filters tend to "depth load" nicely, that is, the largest particles get caught by the outside filter, next smaller on the next layer, and so on. Most filters will actually filter better when they are a little dirty, since the dirt particles on the filter can help capture follow-on particles. Restriction may or may not be a problem. Except at large throttle openings, the restriction is in the throttle body, not the air filter. If the filter is sized properly, it will already pass all the air the carb/fuel injection can handle. Providing more air won't help. You also need to be cognizant of possible problems (not ours) where the fuel injection system uses a hot-wire air-flow sensor when using oiled filters like the K&N. if the filter is excessively oiled, and some of the oil gets on the sensor, you get to buy a new sensor, which isn't cheap. I'm guessing, for most of us, that the stock paper filter will work well enough. When I replaced the stock filter after 20K miles with another stock filter, there didn't seem to be any change in performance, despite the layer of dead bugs and dust on the old filter.

[Gluff]

My biggest reason for going with the K&N over a stock replacement, is reducing my ownership costs. The K&N cost me $61.51, yet is cleanable and reuseable for the life of the bike. If I remember right, the stock filter costs about $35, and with a recommended change interval of 12000 miles, that adds up to alot of cost over a 100,000+ mile lifespan, as compared to the Non-recurring cost of the K&N. The additional airflow is just an added bonus, as far as I'm concerned. All that being said, I'd like to take the time to read that link!

[Jimding]

I thought the same thing, except it will take me 3 or 4 years to put on enough miles to clean the K&N, at which point I will have lost the clean/recharge kit, so I'd need to buy a new one, which eats into the savings substantially. But for the guys that put on 20K miles a year, the K&N is probably a no-brainer.

[Gluff]

I've had my bike for 7 months and am at 13.5K miles, so the numbers definitely work in my favor. Also, I had the K&N recharge kit from my last bike, so no additional expense there, but I do concede your point.

[K2-]

I read a test that showed that the K&N had better airflow than stock until the filters got a little dirty. The stock filter worked OK and the K&N worked worse. So, the message is, you need to keep the K&N clean to have an advantage. Let it get dirty and you'll be at a disadvantage. If your bike is running lean now, it may run very lean with a K&N filter installed.

Beware of "tests" and who has done them, to what standard does it follow, etc. I could do a test in my living room but the results would be meaningless unless I've set it up in a tightly controlled environment. Personal experiences form opinions and that's fine but this is about baseline level testing and which one(s) flow best in exactly equal conditions.

Did you read the link? If a clean stock filter flows worse than a clean K&N filter, how would the clogging of air passages in the stock filter create a higher flow? Stock filters on a graph showing air flow don't go up and down over time...they go down. So do K&N filters, they go down over time as well. Equal amounts of dust added over equal time has shown to result in the K&N flowing more air than the stock. A quote from the SAE test results "the K&N filter was less restrictive than the Fram paper filter both when it was new, and even later when it became dirty."

So please provide a link or some more information on this test that showed the opposite. I and prob most others would be very interested in reading that, what kind of test standards they used, how they set it up, etc. If it was some blogger talking about how he added one to his Honda and swears he got better performance, then it's pure garbage. That was my reason for seeking out this write up. Everything online I can find is pure opinion and totally subjective...to me that's garbage. I like to compare apples to apples and make my personal decisions based on that, but everyone's different.

I believe peoples personal experiences with what they've noticed, and respect the opinions formed from that, but I don't use their opinions to form my own.

All in all I can't understand why anyone would use a paper filter. Both K&N and Foam capture way more dirt which no sane person wants to get inside his engine. On that alone (toss out any claimed performance gains) I'd buy either one of those style filters. The stock ones are mass produced 10 cent or less (cost) filters made as cheaply as possible. They're only designed to just meet the requirements of industry. These other brands are the "aftermarket" and are constantly fighting each other to blow the stock filters out of the water.

On a side note, I defy someone to show proof of a real racing team out there that prefers the stock filters. Don't come back with a stock team that is obligated to use one because Fram is their #1 sponsor. I used the word "prefers".


That's my $.02

[hotshoetom]

Beware of "tests" and who has done them, to what standard does it follow, etc. I could do a test in my living room but the results would be meaningless unless I've set it up in a tightly controlled environment. Personal experiences form opinions and that's fine but this is about baseline level testing and which one(s) flow best in exactly equal conditions.

Did you read the link? If a clean stock filter flows worse than a clean K&N filter, how would the clogging of air passages in the stock filter create a higher flow? Stock filters on a graph showing air flow don't go up and down over time...they go down. So do K&N filters, they go down over time as well. Equal amounts of dust added over equal time has shown to result in the K&N flowing more air than the stock. A quote from the SAE test results "the K&N filter was less restrictive than the Fram paper filter both when it was new, and even later when it became dirty."

So please provide a link or some more information on this test that showed the opposite. I and prob most others would be very interested in reading that, what kind of test standards they used, how they set it up, etc. If it was some blogger talking about how he added one to his Honda and swears he got better performance, then it's pure garbage. That was my reason for seeking out this write up. Everything online I can find is pure opinion and totally subjective...to me that's garbage. I like to compare apples to apples and make my personal decisions based on that, but everyone's different.

I believe peoples personal experiences with what they've noticed, and respect the opinions formed from that, but I don't use their opinions to form my own.

All in all I can't understand why anyone would use a paper filter. Both K&N and Foam capture way more dirt which no sane person wants to get inside his engine. On that alone (toss out any claimed performance gains) I'd buy either one of those style filters. The stock ones are mass produced 10 cent or less (cost) filters made as cheaply as possible. They're only designed to just meet the requirements of industry. These other brands are the "aftermarket" and are constantly fighting each other to blow the stock filters out of the water.

On a side note, I defy someone to show proof of a real racing team out there that prefers the stock filters. Don't come back with a stock team that is obligated to use one because Fram is their #1 sponsor. I used the word "prefers".


That's my $.02


well said...well said...couldna said it better meeself! :)