Oil vs. Paper Air Filters--The RRRRest of the Story!

[Tom and Amanda Lang <rustnrot@domain.elided>]

Who came up with the paper air filter in the days of yore?  Carl Kiekhaefer
of Kiekhaefer Mercury Outboards did, in 1955.  Carl was a *very* successful
stock car racer (was inducted into the Stock Car hall of Fame in 1980), and
was the envy of the auto companies themselves with his methodical,
perfectionist approach to racing.  Anyway, the story goes (according to
"Iron Fist" by Jeffrey Rodengen) like this:  Carl's Chrysler C300's (with
331 cubic inch Hemi) were getting ruined by dirt ingestion.
Reason:  "We found that for racing, the conventional oil-bath air filter is
inadequate.  It actually collects dirt and dumps it in big gulps into the
carburetor.   At full throttle we would suck oil and dirt right out of the
filters themselves.  We'd be better off with no filter". . . "So we drew on
our experience in building portable chain saws for the government during
the war.  We knew that dry paper filters had worked there under dusty
conditions.  So we tried paper."  "We improvised a filter from the
sawed-off bottom of a garbage can.  We built one inside an aluminum
saucepan.  Finally, with the help of Purolator parts, we came up with the
simple, but amazingly efficient dry paper filter that all racers and
conventional automobiles use today."

Story goes on to say they got the paper filters to "keep out all dirt
particles over two microns in diameter".  Credit is given in the book that
this information came from the Feb. 1956 Popular Mechanics article, "How to
Win Stock-Car Races" for those of you that happen to have that issue handy!

**Now you know the RRRest of the Stttoorry**

My comments:

1. The oil bath filter, although effective, appears more restrictive than a
paper filter.  The above and what I have read on the I-H Digest posts seems
to bear this out.
2. Without any real data, (exactly to what degree, in microns, is an oil
bath filter effective, anyway?) I *suspect* that a given oil bath filter
will *not* filter down as finely as a good paper filter.  However, the oil
bath filter seems to filter "good enuf" for low cfm engines that don't have
*exacting* tolerances (e.g. old I-H iron, tractors, etc.)  It also appears
that an oil bath can take-up more dust before it must be changed/cleaned
than a paper filter.
3. With all that said, how does a K&N filter work--it has both *oil* and
*paper*, doesn't it?  It is impregnated with oil, correct?  How does one
"clean-it"--I hear that's what you're supposed to do, without leaving some
grit behind, and invariably, some grit, as a result of the cleaning, is now
on the *inside* of the filter.  Anyway, the previous logic (paradigm,
probably) has worried me and for these reasons (correct me as wrong,
please), I elect to buy paper elements and throw them out when dirty.
Thoughts, comments??