Date: Tue Jul 26 08:22:36 1994   
From: jgd@dixie.com (John De Armond)
Subject: Re: aeroquip for webers

>Ok, my curiosity is piqued, John.  I thought that K&N's were supposed
>to be the trick thing to use for air filtering?  Also, do you have any
>good ideas about routing a duct to the windshield cowling?  Would it
>make that big a difference in terms of hp? (or any at all?)

K&N is simply the company that spends the most ad dollars and therefore
gets the most attention.  I learned my very expensive K&N lession
over 20 years ago when I was actively building racing engines.  K&N
had some contingency money available so I replaced our Filtron
(Oiled foam) filters on our motocross bikes with K&N.  An engine that 
would normally last 10-15 heats was completely trashed by dirt 
before the first one was over.  Frankly I've never seen such massive
filter failure.  Figuring it was a fluke, I tried it again at 
another race.  Same result.  Massive wear, grit all over the 
intake track - trashed engine.  Lesson learned.  The K&N that 
came on a used Z I bought awhile back is exactly the same 
construction as the 20 year old filter still somewhere in my junk
collection.

K&N follows a familiar path.  Lots of hype, lots of advertising 
dollars which effectively buys them good press, and an excellent
no-questions-asked warranty.  A warranty that pays people off
to keep 'em quiet.  One can get away with a lot on the street 
simply because there isn't much dirt under normal conditions.
But off-road is another matter.  There is an easy test of a
filter that you can do.  Simply thoroughly clean the air cleaner
housing and the carb intake.  Then coat it with a very thin coating
of light grease.  A portion of any dirt that gets through the filter
will be trapped in the grease.  Run it awhile and then feel the grease.
If it is gritty, the filter isn't working.  It will be gritty with
a K&N.

There is simply no better filtration media than paper.  The very best
filters, HEPA filters, used to catch sub-micron particles in nuclear
plants and hard disk drives, is simply a very refined paper.  If the 
paper element doesn't flow enough air, install a larger one.  The only
time I won't use a paper element is when there is a possibility that
the filter element can become wet.  Then I'll use oiled foam.  For
REALLY dusty environments such as dirt tracks and off-road racing,
I'll do like every other mechanic and use a foam prefilter over
a paper element.

As far as picking up air under the cowl, you can simply go through the 
firewall above the partition that separates the cowl space from
the interior.  I've done that with stock carb setups.  Depending on how
far the horns of the webers stick out, this may or may not be easy.

John