Try this again...A friend of my sent this to me about K&N filters,
interesting ain't it??
Richard Seaton
RSH17@msn.com
View My 1969 TR6 restoration @
(http://groups.msn.com/Richards69TR6Restoration)
OR
http://www.triumphowners.com/registry.cgi?sectionID=111014&vehicleID=92
Gentlemen,
Interesting facts published on the Turbo Board. If these tests are accurate
then it makes me wonder if my Triple throat K&N's are only catching
.............kangaroo's?
Wonder if solid foam style filters with my K&N Weather Shields are better
for the street? Anyone have any idea's?
Rich H.
Subject: [TurboBoard] Re: Green Air Filter
Date: Mon, 13 Feb 2006 13:31:05 -0600
This was a scientific test, not one done by filter manufacturer X to
show that their filters are better than manufacturer Y. The test
results are pretty irrefutable as the test lab tests and designs
filters where "screw ups" are absolutely NOT allowable (I can't say
any more for security. Think "Glow in the Dark").
A scientific test was done on TEST filters where air was loaded with
ACCTD (some standardized "test dust" called AC Coarse Test Dust) and
sucked through the TEST filter then through an analysis membrane.
>From the Quantity of dust injected and the amount that gets through
the TEST filter and is then captured on the analysis membrane we can
calculate the efficiency of the TEST filter in Question.
BMW Stock Filter, Eff. Area of Media: 8.4 sq ft.
K&N Replacement, Eff. Area of Media: 1.6 sq ft.
The filters are the SAME size. They both fit in the STOCK BMW M3
airbox. The difference is that the STOCK filter has 65 pleats 1.5"
deep and the K&N only 29 pleats each 0.75" deep.
Now, remember this ratio: " 5.25:1". It's the ratio of the AREA of
STOCK to K&N. It's very important and will come into play later.
The STOCK filter efficiency started at 93.4% at 0 loading and
increased to 99.2% efficiency as the loading increased to a max
tested of 38.8 gm/sq ft of dust.
The K&N filter efficiency started at 85.2% at 0 loading and
increased to 98.1% at the max tested loading of 41.38 gm/sq ft.
Now, I hear you. "Jim, that's only a FEW PERCENT". But is it?
Let's look. If we had 100 grams of dust on a new BMW filter we
would let thro!
ugh a total of 6.6 grams of dust in. If we used the new K&N filter
we get 14.8 grams of dust. That's 224% (TWO HUNDRED TWENTY FOUR
PERCENT!!) more dust ingested initially, stock vs. "free flow" and
this ratio is pretty much held. Somewhere between 200-300% more
dirt gets "ingested" anywhere across loading equivalence. The more
INTERESTING thing is when you look at what happens to the DP or
Differential Pressure at a constant airflow as you dirty both
filters equally with time.
The test used a rate of 75gr of dust per 20 min. Here's where the
AREA difference comes MAJORLY into play. See, even though the BMW
filter flows a bit less at the SAME loading, it also LOADS UP 5.25
times SLOWER due to it's LARGER effective area. So what happens is
that the K&N initially flows better, but as the dirt continues
coming in, the K&N eventually flows WORSE while still letting MORE
dirt in.
Now, does any of this additional dirt cause problems? I dunno. I
suppose we!
could have a few people do some independent oil analyses on
different motors using both K&Ns and Stock filters. Get enough of
them, and you'd have a good statistical basis. For me though, it's
simple: More DIRT = BAD.
The additional short-term airflow might make sense on a track car.
IMHO, it doesn't for the street.
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