[TR] Independent air filter test

[Mark Hooper]

Hi Michael:

Those are indeed good ideas for measuring, but the subject is trickier than
one might imagine. (In a different lifetime I used to develop testing
equipment in the pulp & paper industry.) Comparing paper before and after any
process involves having to control humidity to rather a precise degree. Bone
dry weight is quite different from when at normal atmospheric humidity. Lignin
levels, fibre diameter, curl etc could all have changed due to the abrasive
effect of the air flow. (I refer to his test sheets of course, not the primary
filter media being compared which are different types of material).

Ceteris paribus, I think that the colour test the guy has done has probably a
very good relative value. Absolute measurement level is definitely debatable.

I'm a great believer in using K&Ns (I have them on my triple Stromberg setup),
but I don't have any difficulty in believing that they provide less filtration
than a more restrictive paper filter. Less resistance to air flow just has to
mean less obscuring material and shorter mean particle path through the filter
web. For me, I have found that the TR6 is prone to running over rich due to
input restrictions as the filter fills in. Running jet black with soot is
surely tougher on the engine and exhaust than a bit of extra micro-dust.
Anyway, I live near a lake in a humid environment; dust is less of an issue
than pollen. And that sticky stuff gets caught by my K&Ns pretty well, judging
by the strange colours they turn during the season.

Overall, for me the deciding factor is that the K&Ns look nicer than the
standard paper units. And despite all the scientific discussion being pushed
around, that is really why I installed the things.

Best regards,

Mark



-----Original Message-----
From: triumphs-bounces at autox.team.net [mailto:triumphs-bounces at autox.team.net]
On Behalf Of Michael Porter
Sent: April 22, 2010 6:44 PM
To: thenicholls at verizon.net
Cc: triumphs at autox.team.net; jmwagner at greenheart.com
Subject: Re: [TR] Independent air filter test

thenicholls at verizon.net wrote:
> Justin, Randall and list,
>
> Did some searching around and found this test very interesting:
http://www.bobistheoilguy.com/airfilter/airtest1.htm
>
>
I'd already put in a couple of cents' worth on this thread, but, I guess
it was too big.  This test reminds me of a couple of things from the
heavy-duty diesel market.  Filtration is a big deal with big
diesels--every manufacturer wants high mileage between rebuilds because
that's a reputation builder.  I know of no HD diesel manufacturer that
has certified K&Ns for use.

More importantly, they do test filters.  One of the things that was
found was paper filters get better over time (up to a point), and the
general recommendation was that instead of changing them frequently, the
filter should be cleaned, not by blowing air through the filter, but by
tamping them on a hard surface to shake off the surface dust, clean the
housing and reinstall, and change the filter every other cycle (or if
the filter drop reached 28-30" H2O--this certainly wouldn't be
recommended with a naturally-aspirated engine, but, all diesels today
depend upon turbos and the suction on the inlet side of the turbo is far
higher than for a conventional gasoline engine).  The thinking was that
larger particles blocked smaller openings in the weave of the paper and
kept more small particles out.

That said, the testing mentioned at the link above certainly could have
been more scientific.  Color is only a rough indicator.  I would have
been more impressed with a test that took a tare weight of the second
filter, and weighed each sample to see the total filter load by weight,
and an analysis by particle size would have been more illuminating, but,
that's probably beyond the guy's research budget.


Cheers.

--


Michael Porter
Roswell, NM