Re: K&N filters

[Desertmax@xxxxxxx]

In a message dated 99-01-08 03:57:12 EST, you write:

<< tomas s. perez wrote about if thre was any scientific data if the k&n
filters
 actually helped.  I just installed one on my 90 325is, and could not tell a
 difference. >>

Although ti does not specifically involve BMW's, I'd like to share comparative
data I got from the Vmax list. Vacuum measurements (flow resistance) made with
a test airbox yielded the following results:

stock box  w/ filter 100%
stock box w/ K&N 100%
stock box w/o filter 100%
modified airbox (trimmed) w/filter 62.5%
modified w/K&N 56%
individual filters 44%
manifold only 37.5%


I would expect similar results with any stock unmodified setup, and noticeable
improvements after polishing/porting the head(s). High flow only affects top
end, meaning close to redline. Best tested on the drag strip.
Of course, other factors involve maintenance and filtration capability. To
maintain good filtration performance on the K&N's regular cleaning and
application of filter oil is necessary. Remember that K&N wfilters were
developped with race engines in mind. Those engines got frequently  overhauled
and longevity is not necessarily a stronghold. my $0.02

Bert
looking out for a newer model 32xiC
1500cc Vmax

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