On 5/19/2012 12:17 PM, Mark Hooper wrote:
> In the past I have installed K&N filters on my motorcycles and my TR6 for the
> following highly technical reasons:
>
> /start technical reasons
>
> 1 - They look pretty.
> 2 - They let me fit nice shiny filter enclosures
>
> /end technical reasons
>
> They certainly do flow more easily than paper filters.
I've only had limited experience with a K&N. My GT6 came with ones
that, admittedly, hadn't been properly maintained (hadn't been cleaned
and oiled to spec). It also burned oil at a prodigious rate. When I
did an emergency ring job on it, the cylinders looked as if they'd been
smoothed with fine sandpaper (virtually all engines that have been
broken in properly and had the oil and filter changed to schedule will
retain some evidence of honing underneath the cylinder glaze--this one
had none).
That said, most heavy-duty transit engines still use big canister-type
paper filters. When I first started in that business, there were a
number of failures of Donaldson filters, which Donaldson tracked down to
shops using compressed air to blow dirt off of and out of the filters.
Even at fairly low pressures, that practice produced microscopic tears
that allowed quite a bit of dirt to pass through the filter, so they
began recommending that their filters be tapped gently to dislodge caked
dust and be reused until they no longer met specs, since they had found
that the finest dust particles tended to plug the pores in the paper
advantageously--they stopped the small particles from passing the
element. (This is a practice that's probably unsuitable for
normally-aspirated gasoline engines, since most big diesels today have
turbos assisting cylinder charging, which means they can tolerate a
bigger pressure drop across the filter, and most HD diesels have _really
big_ filters with lots of excess capacity.)
But, still, most cars today typically run paper filters, and thanks to
the minimal bore-washing that occurs with good engine management and
fuel injection, will typically run several hundred thousand miles with
regular maintenance. Moreover, for most Triumphs, the real limiting
factor for flow is the engine itself, not the carburetors or the air
filters.
Cheers.
--
Michael Porter
Roswell, NM
Never let anyone drive you crazy when you know it's within walking distance....
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