K&N filtering capacity??
06-09-2002, 05:50 AM
#11
Registered User
The first time I bought a K&N filter it was for my CR-X. Throttle response was improved, and I loved it. Didn't keep that car too long...
The second time was for my GS-R. Bought it new and used it for about 5,000 miles. I pulled my intake tube to clean and shine it, and to my suprise there was a film of oily dirt on the inside. Some of this was also building up on my throttle butterfly. Needless to say I put the stock setup back in and never had the dirt problem again.
I also had a friend who decided to relocate the intake source to the fender well of his GSR. He put a K&N filter there, and removed the stock filter from the box. I told him my experience, and he said he could easily put his stock filter back in the box. Since our filters were already dirty, and I already decided I would be using stock filters again, I bought a new one for the experiment. Three weeks later we looked at this filter which was downstream from a K&N. There was a shocking amount of fine oily dirt on it!
Would I use a K&N filter again? Definitely not. The amount of filtration is inversely proportional to the amount of dirt removed. You can cheat, but you're not going to win in the long run. And to know that oil is coming off the filter and could be fouling my sensors, I definitely am not interested in having an unknown oil being sucked into my engine.
Here's a quote I found on the internet that sums it up pretty well. Bold highlight was me.
"Pleated Gauze or Fabric Filtration (K&N)
This is another screen type that is only 1mm thick. If the dirt is not
stopped on the surface, it is not stopped at all! These filters are sold on
the pretense that they maintain an oil curtain for the air to pass through,
thereby catching all dirt particles. It is impossible to maintain an oil
curtain. The oil soaks the threads of the gauze or cloth, but does not span
the openings; otherwise, the air could not get through. The dirt particles
that do hit the threads have a good chance of being caught; the others
simply go through. The reason the filter does not look dirty on the inside
is because the dirt went into the engine. You can easily demonstrate this
fact yourself by coating the inside of your housing or carb throat with a
thin layer of grease to trap some of the dirt not caught by the filter or
you can place a foam filter inside the gauze element to prove the same
thing.
The one advantage that this type of element has over paper is greatly
reduced airflow restriction; however, poor filtration efficiency is the
price you pay. When dirt builds up, filtering action improves, but now the
airflow is poor like paper elements."
I find it amazing that there are so many posts dedicated to when to change the oil and filter the first time, but everybody seems to accept that a filter that flows more junk into the engine the entire life of the car is perfectly fine.
A perfect answer to getting less restriction is to increase the surface area. Since most filters are maxed out on what can be accomplished through pleating, installing a Y-pipe and an additional stock filter is what I would suggest.
The second time was for my GS-R. Bought it new and used it for about 5,000 miles. I pulled my intake tube to clean and shine it, and to my suprise there was a film of oily dirt on the inside. Some of this was also building up on my throttle butterfly. Needless to say I put the stock setup back in and never had the dirt problem again.
I also had a friend who decided to relocate the intake source to the fender well of his GSR. He put a K&N filter there, and removed the stock filter from the box. I told him my experience, and he said he could easily put his stock filter back in the box. Since our filters were already dirty, and I already decided I would be using stock filters again, I bought a new one for the experiment. Three weeks later we looked at this filter which was downstream from a K&N. There was a shocking amount of fine oily dirt on it!
Would I use a K&N filter again? Definitely not. The amount of filtration is inversely proportional to the amount of dirt removed. You can cheat, but you're not going to win in the long run. And to know that oil is coming off the filter and could be fouling my sensors, I definitely am not interested in having an unknown oil being sucked into my engine.
Here's a quote I found on the internet that sums it up pretty well. Bold highlight was me.
"Pleated Gauze or Fabric Filtration (K&N)
This is another screen type that is only 1mm thick. If the dirt is not
stopped on the surface, it is not stopped at all! These filters are sold on
the pretense that they maintain an oil curtain for the air to pass through,
thereby catching all dirt particles. It is impossible to maintain an oil
curtain. The oil soaks the threads of the gauze or cloth, but does not span
the openings; otherwise, the air could not get through. The dirt particles
that do hit the threads have a good chance of being caught; the others
simply go through. The reason the filter does not look dirty on the inside
is because the dirt went into the engine. You can easily demonstrate this
fact yourself by coating the inside of your housing or carb throat with a
thin layer of grease to trap some of the dirt not caught by the filter or
you can place a foam filter inside the gauze element to prove the same
thing.
The one advantage that this type of element has over paper is greatly
reduced airflow restriction; however, poor filtration efficiency is the
price you pay. When dirt builds up, filtering action improves, but now the
airflow is poor like paper elements."
I find it amazing that there are so many posts dedicated to when to change the oil and filter the first time, but everybody seems to accept that a filter that flows more junk into the engine the entire life of the car is perfectly fine.
A perfect answer to getting less restriction is to increase the surface area. Since most filters are maxed out on what can be accomplished through pleating, installing a Y-pipe and an additional stock filter is what I would suggest.
06-09-2002, 06:42 AM
#12
Registered User
I installed the AEM CAI several months ago and have been running with their filter. When I took that filter off a couple of weeks ago, it was SO fouled with junk....I washed the filter and had an actual pile of dirt in the bottom of the bowl. I have no idea how much, if any, dirt made it through the filter, but I didn't like the fact that so much was being caked on and reducing airflow.
So, with a quick trip to Home Depot and the purchase of a 3" rubber connector, I was able to insall the filter I picked up from MG Racing that was originally installed in my stock airbox. When THIS one gets dirty, I just blow it out with air, no oiling necessary. As with the other one, I have no idea how much, if any, dirt is getting through the filter.
I CAN say that this filter tones down the AEM rumble slightly, for what that's worth.
So, with a quick trip to Home Depot and the purchase of a 3" rubber connector, I was able to insall the filter I picked up from MG Racing that was originally installed in my stock airbox. When THIS one gets dirty, I just blow it out with air, no oiling necessary. As with the other one, I have no idea how much, if any, dirt is getting through the filter.
I CAN say that this filter tones down the AEM rumble slightly, for what that's worth.
06-09-2002, 08:53 AM
#14
Registered User
Here's another comment:
"John: If I wrote "subjective" I meant "objective".. I was
responsible for evaluating re-usable air filters
for a major construction/mining company that had
hundreds of vehicles ranging from large earthmovers
to pick-up trucks and salesmen's cars. This study
was embarked upon due to the fact that we were
spending upwards of $30,000 a MONTH on paper air
filters. Using them one time then throwing them
away.. I inititated the study in that I was convinced
that a K&N type filter or oiled foam would save us
many dollars per year in filter savings, man hour savings,
and of course engines as these would filter
dirt better than paper. (yes, I had read the K&N ads and was
a believer)
Representative test units were chosen to give us a
broad spectrum from cars right through large front
end loaders. With each unit we had a long history
of oil analysis records so that changes would be
trackable.
Unfortunately, for me, every single unit having
alternative re-usable air cleaners showed an immediate
large jump in silicon (dirt) levels with corresponding
major increases in wear metals. In one extreme
case, a unit with a primary and secondary air cleaner,
the secondary (small paper element) clogged
before even one day's test run could be completed.
This particular unit had a Cummins V-12 engine
that had paper/paper one one bank and K&N/paper on
the other bank; two completely independent
induction systems. The conditions were EXACTLY
duplicated for each bank yet the K&N allowed so
much dirt to pass through that the small filter became
clogged before lunch. The same outcome occured
with oiled foams on this unit.
We discontinued the tests on the large pieces almost
immediately but continued with service trucks,
formen's vehicles, and my own company car. Analysis
results continued showing markedly increased
wear rates for all the vehicles, mine included.
Test concluded, switched back to paper/glass and all
vehicles showed reduction back to near original levels
of both wear metals and dirt. I continued with
the K&N on my company car out of stubborness and at
85,000 miles the Chevy 305 V-8 wheezed its
last breath. The top end was sanded badly; bottom
end was just fine. End of test.
I must stress that EVERYONE involved in this test
was hoping that alternative filters would work as
everyone was sick about pulling out a perfectly good
$85 air cleaner and throwing 4 of them away
each week per machine...
So, I strongly suggest that depending upon an
individual's long term plan for their vehicles they simply
run an oil analysis at least once to see that the
K&N or whatever alternative air filter is indeed working
IN THAT APPLICATION... It depends on a person's priorities.
If you want performance then indeed the K&N is the
way to go but at what cost???"
"John: If I wrote "subjective" I meant "objective".. I was
responsible for evaluating re-usable air filters
for a major construction/mining company that had
hundreds of vehicles ranging from large earthmovers
to pick-up trucks and salesmen's cars. This study
was embarked upon due to the fact that we were
spending upwards of $30,000 a MONTH on paper air
filters. Using them one time then throwing them
away.. I inititated the study in that I was convinced
that a K&N type filter or oiled foam would save us
many dollars per year in filter savings, man hour savings,
and of course engines as these would filter
dirt better than paper. (yes, I had read the K&N ads and was
a believer)
Representative test units were chosen to give us a
broad spectrum from cars right through large front
end loaders. With each unit we had a long history
of oil analysis records so that changes would be
trackable.
Unfortunately, for me, every single unit having
alternative re-usable air cleaners showed an immediate
large jump in silicon (dirt) levels with corresponding
major increases in wear metals. In one extreme
case, a unit with a primary and secondary air cleaner,
the secondary (small paper element) clogged
before even one day's test run could be completed.
This particular unit had a Cummins V-12 engine
that had paper/paper one one bank and K&N/paper on
the other bank; two completely independent
induction systems. The conditions were EXACTLY
duplicated for each bank yet the K&N allowed so
much dirt to pass through that the small filter became
clogged before lunch. The same outcome occured
with oiled foams on this unit.
We discontinued the tests on the large pieces almost
immediately but continued with service trucks,
formen's vehicles, and my own company car. Analysis
results continued showing markedly increased
wear rates for all the vehicles, mine included.
Test concluded, switched back to paper/glass and all
vehicles showed reduction back to near original levels
of both wear metals and dirt. I continued with
the K&N on my company car out of stubborness and at
85,000 miles the Chevy 305 V-8 wheezed its
last breath. The top end was sanded badly; bottom
end was just fine. End of test.
I must stress that EVERYONE involved in this test
was hoping that alternative filters would work as
everyone was sick about pulling out a perfectly good
$85 air cleaner and throwing 4 of them away
each week per machine...
So, I strongly suggest that depending upon an
individual's long term plan for their vehicles they simply
run an oil analysis at least once to see that the
K&N or whatever alternative air filter is indeed working
IN THAT APPLICATION... It depends on a person's priorities.
If you want performance then indeed the K&N is the
way to go but at what cost???"
06-09-2002, 09:05 AM
#15
Maybe we need to re-think re-useable air filters. If someone has a contact at K&N, it would be nice to see what their reaction is to this information and what their rebuttal would be.Maybe this is why K&N is so confident about their so called "miilion mile warranty". No vehicle with their filter will ever get there.
06-09-2002, 09:11 AM
#16
Registered User
I would be interested in how many MAP sensor failures match rides with oiled filtration intakes.
I posted a poll, we'll see if there is a connection...
https://www.s2ki.com/forums/showthread.php?...&threadid=66272
I posted a poll, we'll see if there is a connection...
https://www.s2ki.com/forums/showthread.php?...&threadid=66272
06-09-2002, 09:31 AM
#17
Registered User
06-09-2002, 02:50 PM
#18
Registered User
Thread Starter
Thanks for the testimonial. I remember from my prelude forum days that someone else did this test where they stuck a filter behind the K&N and that showed that the K&N was letting dirt pass.
If I am not mistaken, our paper cone filtre looks like it has oil on it too.
If I am not mistaken, our paper cone filtre looks like it has oil on it too.
06-09-2002, 03:05 PM
#19
But has anyone put a regular filter behind another regular filter and see what the consequences are. I don't doubt what was discovered with the K&N but sometimes we get a bit of tunnel vision or the "bug in the headlight" syndrome. Sort of like the vacuum salesman comes to your house, dumps a pile of dirt on your carpet, tells you to suck it up with yours and then does a suck with his and shows you all the dirt it picked up.
Know how you get a brand new car and someone says you should clay bar it and see how much stuff comes off it? I wonder if you were to clay bar that same car a second time right away, how much stuff you'd get.
Although it may be alarming to see news llike this when we were "happy in our ignorance" before the news, I'm not that concerned about the amount of dirt that might be getting into the engine. Dirt has been getting into engines for as long as engines have been around. Maybe we just have never known how much. Isn't that part of why engine oil gets dirty and why there is an oil filter? .............. To take care of this very problem?
I'd still like to hear K&N's response to all of this.
Know how you get a brand new car and someone says you should clay bar it and see how much stuff comes off it? I wonder if you were to clay bar that same car a second time right away, how much stuff you'd get.
Although it may be alarming to see news llike this when we were "happy in our ignorance" before the news, I'm not that concerned about the amount of dirt that might be getting into the engine. Dirt has been getting into engines for as long as engines have been around. Maybe we just have never known how much. Isn't that part of why engine oil gets dirty and why there is an oil filter? .............. To take care of this very problem?
I'd still like to hear K&N's response to all of this.
06-09-2002, 06:46 PM
#20
Registered User
Well, by K&N's own admission the filter works better when it gets a little dirty. Until then, it must let more dirt get by (what else could it mean?)
I think a second filter will always catch something that gets by the first filter, true. But what worries me is particle size. Up until the K&N has "caught" enough particles to supplement the blockage that catches the dirt, quite a few larger particles have gotten by.
Take a look at a layer of gauze sometime, and notice how big the holes are. They can only overlap so many layers, so there will always be some significant holes based on the way the "screens" line up. There is higher velocity and air flow at these points, and what's being relied upon is the surface tension of the oil to catch the dirt (if it gets a chance). So a K&N filter "catches" the lighter, fluffy dirt that can't cause as much damage, while the harder grainy dirt gets by and adds to the grit in your cylinder (where it probably does some damage before it's small enough to get by the rings and into the oil).
OK, so I haven't seen particle size information like you can easily find for oil filters (mainly because it's easier to capture and measure dirt in liquid). But what I've seen at 10X is enough to bother me!
I think a second filter will always catch something that gets by the first filter, true. But what worries me is particle size. Up until the K&N has "caught" enough particles to supplement the blockage that catches the dirt, quite a few larger particles have gotten by.
Take a look at a layer of gauze sometime, and notice how big the holes are. They can only overlap so many layers, so there will always be some significant holes based on the way the "screens" line up. There is higher velocity and air flow at these points, and what's being relied upon is the surface tension of the oil to catch the dirt (if it gets a chance). So a K&N filter "catches" the lighter, fluffy dirt that can't cause as much damage, while the harder grainy dirt gets by and adds to the grit in your cylinder (where it probably does some damage before it's small enough to get by the rings and into the oil).
OK, so I haven't seen particle size information like you can easily find for oil filters (mainly because it's easier to capture and measure dirt in liquid). But what I've seen at 10X is enough to bother me!
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