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Date: Tue Jul 26 08:22:36 1994   
From: 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

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.


From: John De Armond
Newsgroups: rec.outdoors.rv-travel,alt.rv
Subject: Re: How to void yer warranty
Date: Sun, 18 Apr 2004 17:42:29 -0400
Message-ID: <>

On Fri, 16 Apr 2004 18:54:38 -0500, "Mike Simmons" <> wrote:

>Speaking as a service manager for DaimlerChrysler, both D/C and Cummins
>"specifically" recommend NOT using a K&N or similar filter on Cummins turbo
>diesels because the filtration is inferior to the OEM filter.  See the
>Cummins website for more info.
>Also, IMHO the HP/torque claims for the K&N are snake oil.

Same experience here.  Cost me two racing engines before the light came on.
Engines that should have lasted a season were toast after only one event on a
dirt track.  Pistons, rings and valve stems just ground to bits.  My mentor
suggested this simple test.  Smear a very thin film of grease on the inside of
the intake tract downstream from the air filter.  Run the vehicle for awhile,
then examine the grease.  If dirt is getting past the filter there will be
grit trapped on the grease.

I did that and sure enough, the grease felt like valve grinding compound.
That piece of sh*t K&N wasn't doing much of anything.

K&N had been offering relatively huge contingency money and that partially
distracted me away from properly testing the product before using it in a
race.  Hard lesson learned.

One must ask, if the damned thing is so good then why doesn't it appear on any
OEM product?  Given the EPA mandated drivetrain emission warranties, an OEM
would do anything cost-effective to extend engine life.  Actually they are.
They're using the best filter media available for dry environments - pleated
paper.  For wet environments, oiled foam is the best there is, though it isn't
as good as paper.  For very dusty environments (desert racing, dry dirt
tracks, etc) oiled foam over paper is the best.

Rather than wasting money on a K&N, if one wants (maybe) minimal performance
at the expense of short engine life, simply yank the paper element and leave
the air box open.  That is, in effect, what you're doing when you replace an
OEM air cleaner system with a K&N.  IMHO, one of the worst rip-offs
perpetrated on the gullible.


From: John De Armond
Newsgroups: rec.outdoors.rv-travel,alt.rv
Subject: Re: How to void yer warranty
Date: Sun, 18 Apr 2004 17:53:59 -0400
Message-ID: <>

On Sat, 17 Apr 2004 14:10:22 GMT, Chris Bryant <> wrote:

>On Fri, 16 Apr 2004 19:18:55 +0000, Will Sill wrote:
>>  I was advised today that some
>> GM Duramax owners have become their own warranty station by using
>> oil-coated filters.  It seems the oil mist confuses/destroys the MAF (Mass
>> Air Flow) sensor, and the consequences can be messy.
>Dang- thanks for the heads up. I always thought the Duramax was a good
>engine, but if it is so fragile that a bit of oil mist in the air intake
>can give "messy results", I'll stick to another brand.

It's not the engine, Chris, but the MAF that is at risk.  Both Ford and GM use
the same principle - a heated wire - in their MAFs, though Ford uses a voltage
signal while GM uses a variable frequency signal back to the PCM.  In either
case, contact with oil over an extended period of time will ruin the hot wire
sensor.  The sensor goes through a cleaning cycle fairly often (every shut
down in the case of GM) which heats the wire red hot, burning off the crud.
But deposits remain, just like when an engine burns oil.  Eventually they'll
build up to the point that the wire loses sensitivity.  Although the MAF can
be taken apart and carefully cleaned, most people regard the thing as broken
at that point and replace it with a new one.

It takes a pretty good bit of oil to do the deed.  The MAF is designed to
survive a moderate bit of blow-by that reaches the MAF via the crankcase vent
line.  The tiny bit of oil that a K&N filter retains and then sheds will not
do the deed.  Especially if K&N's recommended oil (low ash) is used.  Even on
highly supercharged hotrods like the Buick GN, for instance, where the blow-by
is large under boost, it takes a year or more of daily driving to kill a MAF.

There are other reasons not to use a K&N (see my other post) but this isn't
one of 'em.  As usual, will swings blindly and just nicks the ball.  No joy at
first, however.


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