Air filters - pro & contra

[Mitko]

As I promised to few club members, here it is: http://home.stny.rr.com/jbplock/ISO5011/SPICER.htm

 

[Richard]

Great article, and if it's all true then I'm one of those suckers that wasted money on K&Ns for our other cars

But then I'm not a believer of 'if it's on the Internet it must be true', so I'll keep pretending I did smart purchases

 

[Mitko]

Well, I know it is a Internet article and it could not be 100% true but it does sence to me and I throw out my k&n right after I read the article.

 

[Richard]

I might reconsider the K&Ns in our street vehicles, but for the Jeep I like it's resistance to water. And the money has already been spent (or is that wasted?).

Also the article doesn't state what is an acceptable amount of 'dirt' to go through the filter, and it doesn't measure what size dirt is captured vs. passed through. A little 80 micron dirt may be damaging but a lot of 2.5 micron dirt might not matter.

Just more food for thought.

 

[Dirk]

Just took a quick look at the chrt, data and interpretation of the "indipendent" data. I find it extreemly odd that one brand, AC Delco, or GM, wins all test...by large margin mostly. The guy doing the tests is a firefighter and tree something or other. Maybe he is qualified, but whatever his qualifications maybe, I did not read them.

Admittedly I am too tired to read the whole thing right now. but for example:
"The AC Delco filter test ran for 60 minutes before exceeding the restriction limit while the AMSOIL and K&N tests each ran for 20 and 24 minutes respectively before reaching max restriction. In 60 minutes the AC Filter accumulated 574gms of dirt and passed only 0.4gms. After only 24 minutes the K&N had accumulated 221gms of dirt but passed 7.0gms. Compared to the AC, the K&N ?plugged up? nearly 3 times faster, passed 18 times more dirt and captured 37% less dirt."

WTF? if you want comperable results, run the test for equal time periods. And, the graph is labeled "Total Dirt Passed vs. Time". yet in the write up he says "The AC Delco filter test ran for 60 minutes before exceeding the restriction limit while the AMSOIL and K&N tests each ran for 20 and 24 minutes respectively before reaching max restriction", what is this magical restiction limit? There is no mention....odd!!!
Then he says that the AC filter captured 574gms (I assume gms is American for gram, abbreviated "g"), over 60 minutes, average of 57.4g/min and passed 0.4g. The K&n captured 221g in 24 minutes or 55.24g/min and passed 7.0g. So it captured nearly the same ammount, not 37% less. That it passed more I believe...it flows more air, it is less restrictive, which means larger "holes" in it...so it lets more through. How large are these particles that get through? how many microns? whatever, I call BULLSHIT on these test results.

An engine is an air pump, less restriction in and out means more flow, therefore more power potential. Potential, not automatic gains, the engine has to be able to use this increased airflow. This holds true for Gas, Diesel, LPG...any engine.

Looks to me like a GM sponsored test disguised an indipendent......:flipoff:

 

[Duct_Taper]

WTF? if you want comperable results, run the test for equal time periods. And, the graph is labeled "Total Dirt Passed vs. Time". yet in the write up he says "The AC Delco filter test ran for 60 minutes before exceeding the restriction limit while the AMSOIL and K&N tests each ran for 20 and 24 minutes respectively before reaching max restriction", what is this magical restiction limit? There is no mention....odd!!!

Actually, if you read right off the top of the article, the "restriction limit" is based on pressure differential - basically, how hard you have to push to get the air through the filter.

"Every filter is initially tested at 350 CFM and the Initial Restriction or differential pressure across the filter is recorded in IN-H20 (Inches of Water). The filter is then tested by feeding test dust at a nominal rate of 9.8 grams per minute with a constant airflow of 350 CFM. The test is continued until the flow restriction exceeds the Initial Restriction + 10 IN-H20."

So what this means is that the K&N and AMSOIL filters plug up faster and the engine ends up working harder to suck the air through them.

Then he says that the AC filter captured 574gms (I assume gms is American for gram, abbreviated "g"), over 60 minutes, average of 57.4g/min and passed 0.4g. The K&n captured 221g in 24 minutes or 55.24g/min and passed 7.0g. So it captured nearly the same ammount, not 37% less. That it passed more I believe...it flows more air, it is less restrictive, which means larger "holes" in it...so it lets more through. How large are these particles that get through? how many microns? whatever, I call BULLSHIT on these test results.

Again, since the test was terminated based on a pressure differential, the K&N filter plugged up after a shorter time with less total dust in it and more total dust passed through. I agree that the rates of dust capture are similar - but the K&N gets clogged more quickly, which negates its advantage in being "less restrictive".

Overall, these tests (if they are legit, and they seem to be) show that the K&N filter is less restrictive than the AC paper filter, but it lets more dust into the engine (not a big surprise) and it clogs up faster and probably, in the long run, ends up being more restrictive (this possibly could be negated by regular cleaning and oiling... but I don't know what the numbers are for average dust ingested through a filter when driving, so I can't say how often you would need to clean it).

 

[Dirk]

Cool. As i said, didn't read the whole thing, was too tired, missed some of the overall parameters of the test.

I wonder how long it would take, under normal (our usage normal not road driving) to accumulate that much "dirt". This may be a good benchmark for K&N filter service, wash & re-oil. I will have to weigh my filter now.

 

[snippy]

Man, after that dirt road to and from the Quinn, I'm feel the need to go out and wash mine as soon as this bloody meeting is over.

 

[Mini-T]

K&N sells a device that monitors the restriction of the filter.
Filter Minder

 

[Richard]

I use a K&N pre-charger on mine http://www.knfilters.com/wraps.htm to keep all the big gunk off and last longer between changes.

 

[Root Moose]

K&N sells a device that monitors the restriction of the filter.
Filter Minder

I have the same kind of device on my grass cutting tractor. May be able to source it cheaper at TSC or similar instead of paying K&N bling charge.

JAT

 

[Dirk]

those type of f;ow indicators are also commonly used on Highway tractors and heavy equipment.

 

[Mitko]

And factory build in some wehicles