RE: Air Filters

[Roger Baker <rbaker@xxxxxxxxxxxx>]

Well Thomas, how about this, on two of my previous cars which ran K&N filters, both had the cotton gauze deteriorate to the point of letting in BIG dirt
particles. If you carefully inspect a K&N over a few years time, as it ages the cotton pulls back from the edges of the pleats & where the rubber ends
are capped on. I've had a previous turbo car suck so many big dirt particles in that they started leaving small streak/impact marks in the compressor
wheel. Good/bad flow aside, I don't want anything on my engine that's gonna make it a time bomb.

Roger

"Fadeev, Alex" <Alex.Fadeev@domain.elided> wrote:

> "Thomas Petersen" <bmw318is92@domain.elided> wrote:
> >
> > Your thougths about the effiency of the filtering is questionable,
> > I find it very hard to beleave that the filter effiency on the K&N
> > is poorer than that of the original! So, that should *not* be the
> > reason for not installing the filter..
>
> Dear Thomas, finding something hard to believe does not, in and of itself,
> disprove a fact or a claim. You need data to support your position. In this
> case data is on the side of Rob Workman's suspicions. Read this reply on the
> subject that Jim C's posted (and I saved) a while back:
>
> <start quote>
> > I was curious if the K&N filter inserts work as well as the stock air
> filter.
>
>   No, they do not.
>
>   Testing, both by a filter lab in the United States, and by a filter
>   lab in the UK under the auspices of the Motor Industry Research
> Association
>   (aka MIRA.. sort of like our SEMA) have shown that they do not.
>
>   The raw results from the US Lab (for the doubting thomases) are posted at:
>
>   http://www.bonnevillemotorwerks.com/dynocharts/intake/KN/kntest.pdf
>
>   This is in Adobe Acrobat PDF format.. you'll need the Acrobat Reader
>   which is of course available from http://www.adobe.com if you don't
>   already have it.  It's free.
>
>   What the results show is that:
>
>   1) The Cotton-Gauze filters let in considerably more dirt (300-500% more)
>      than stock
>
>      and
>
>   2) Very rapidly, the cotton-gauze filters load up and flow WORSE than
> stock
>
>      Where a K&N type filter flows rather well right out of the box, it
> cannot
>      sustain that flow for very long at all.
>
>   As soon as I get "reprint/excerpt" permission from MIRA I will post some
>   information from their tests.
>
>   Jim Conforti
>
> </start quote>
>
> > Another more important issue, is the intake air temperature. If
> > you equip your engine with the cone-type K&N, you should do
> > something to isolate it from the rest of engine compartment.
>
> very true.
> unshielded cone filters (K&N or any other) were reported to yield a net
> _loss_ hp.
>
> > Regards,
> > Thomas Petersen,
> > '92 318iS Coupe - Supercharged to 205HP (with K&N :-))
> >

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