K&N test - suprising

[Mike G.]

I have used a K&N for quite a while in my Legacy but I just read this
recently and now have some doubts. What does everyone else think about the
link below?

Mike

http://www.bobistheoilguy.com/airfilter/airtest3.htm

 

[TG]

Looks like any of the filters will do a fine job at keeping most of the dirt
from the inside of your engine.... I wonder which ones flow the best??? Just
for the record K&N says their filters catch far more dirt after they are
used for a while and have some dirt built up on them...without reducing
flow. TG

 

[Edward Hayes]

I personally like a filter that does a very good job from day one so my
engine doesn't suffer while the dirt is building up on the filter. Why would
I settle for anything less? Just get a OEM or Purolator and change it every
15-30,000 miles for ~12 bucks and I don't need to put up with an oily mess.
I guess I would miss the red cone under the hood so I could not impress my
friends. eddie

 

[Andy Mason]

It's an interesting article, but it didn't cause me to have any doubts about
using the K&N. I didn't buy it for increased performance or filtering, I
bought it because it can be cleaned and reused.

Andy

 

[Tony Hwang]

Hi,
Ever heard of recycling? Economics? It's not a matter of whether you can
buy a 12.00 throw away parts. I use Amsoil foam filter which is better
than K&N. Clean once a year and no oily mess either. If you spray oil
too much, yes, you'll make a mess out of it.
I guess it is a matter of personal choice.
Tony

 

[Verbs Under My Gel]

Looks like any of the filters will do a fine job at keeping most of the dirt
from the inside of your engine.... I wonder which ones flow the best??? Just
for the record K&N says their filters catch far more dirt after they are
used for a while and have some dirt built up on them...without reducing
flow. TG

I'm no fluid dynamicist, but I've a feeling that filters that flow
better also let larger (dirt) particles through.

 

[Carl 1 Lucky Texan]

Seems like a false economy if your car loses thousands of miles off its
'lifespan' and ends up going to the auto 'recyling center' before it may
have with diligent use of a better filter.
If you didn't buy it for its filtering, why run one at all?
When you clean it, what's going down the drain? On your yard? Over the
fence into your neighbor's yard when he's gone?(kidding!)

Carl
1 Lucky Texan

 

[Jerre Bassler]

Amsoil has recently change the air filter and is now called Flowzair.
Amsoil gives you the source of their test procedure.
Amsoil performance conclusion: SAE J726 (iso 5011)

1. averaged 18% greater airflow
2. up to 99.5% cumulative efficiency
3. generates 1.5 to 4.4 time greater dirt-stopping and dirt-holding
filter capacity.

I recently checked out a K&N box and just stated a independent lab
compared filters and gave no source of testing.

 

[Cam Penner]

I'm no fluid dynamicist, but I've a feeling that filters that flow
better also let larger (dirt) particles through.

If you're assuming the same surface area for air to get in,
yeah, it would pretty much have to. If they can get a
larger surface area, they can get more air in with the same
size "holes".

 

[Bill Putney]

I'm no fluid dynamicist, but I've a feeling that filters that flow
better also let larger (dirt) particles through.

Not necessarily. That can be quantified, and is referred to as filter
efficiency: The ratio of resistance to air flow to (inverse) particle
size allowed thru. If what you are saying is true, efficiency of all
filters would be identical, and that is not the case. However,
generally what you said is true. A premium filter should have higher
efficiency if it's truly a "better" filter.

And, since a K&N filters filter better as it accumulates dirt, the
resistance to air flow is probably (certainly) increasing at the same
time - which I think was your point.

Bill Putney
(to reply by e-mail, replace the last letter of the alphabet in my
address with "x")

 

[Del]

I have used a K&N for quite a while in my Legacy but I just read this
recently and now have some doubts. What does everyone else think about the
link below?

Mike

http://www.bobistheoilguy.com/airfilter/airtest3.htm

Fair play to Bob for actually testing the filters out in the first place but
20 + years ago I worked in a plating shop lab and one of my jobs was testing
for spray and particulates under controlled conditions. I am afraid to say
that driving cars about then checking filters cannot not give an even test
sample there are far too many variables to ruin the results the only result
that a scientist would allow would be if one test patch was totally clean. A
true test would require the samples to be run at the same time in the same
enviroment preferably using a vacuum test rig to vector out the variation
caused by the different throttle openings, road conditions, congestion,
following dirty exhausts, wind borne particles, head winds, tail winds,
different vehicle loads etc etc. those with fuel computers will know how
much variance they get doing the same trip day on day
Take the test as interesting but it certainly is not empirical evidence one
filter is better than another
Derek

 

[TW-Ohio]

: K&N test - suprising

From: "Edward Hayes" (e-mail address removed)
Date: 10/16/2003 7:51 PM Eastern Daylight Time
Message-id: <aaGjb.4136$(e-mail address removed)>

I personally like a filter that does a very good job from day one so my
engine doesn't suffer while the dirt is building up on the filter. Why would
I settle for anything less? Just get a OEM or Purolator and change it every
15-30,000 miles for ~12 bucks and I don't need to put up with an oily mess.
I guess I would miss the red cone under the hood so I could not impress my
friends. eddie

I have a Framulator in it now (not nearly as sturdy as OEM, btw), and am
discouraged with the MPG. I had a Mazda Protegé and added a cone filter, and
improved my mpg by ~12% and I was already getting 31mpg in and around town.
I'd like to do the same for my '02 Legacy GT, but there are few that can filter
dirt to the satisfaction of the intake sensors (K&N, Cobb...?). And as I don't
want to spend the $ on a complete intake system when the car only has 23k on
it, I'll try the K&N. if it doesn't work, I'll go with Subie-filters til I get
the tinkering itch in the Spring! then maybe a Cobb CAI system.
Terry - '03 Silver Legacy SE sedan - 36 miles!
'02 Regatta-Red GT wagon 5spd - 23k miles
Yakima / TandeMover / Rockymount rack
To reply, get rid of the "nonsense"

 

[Tony Hwang]

Hi,
IMO, you're throwing it away at that mileage. K&N or Amsoil ones can
be cleaned and reused. Of course cleaning interval is depending on how
dirty it gets. Your throw away filter loses efficiency as it collects
dirt as well.
Tony

 

[TW-Ohio]

Got my K&N today - let you know how it goes... I hope to improve the mpg.
Terry - '03 Silver Legacy SE sedan - 36 miles!
'02 Regatta-Red GT wagon 5spd - 23k miles
Yakima / TandeMover / Rockymount rack
To reply, get rid of the "nonsense"