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Message
Rusty, some of the cones have an opening on
the intake in and another smaller cone that is inside the large cone for
increased filtering area. They don't specify the dimensions of this inner
cone so I conservatively just make it 10% of the total filter area of the larger
cone.
That makes sense Ed. I later saw what they
called an inverted top that had that sort of arrangement. With
the size I could use, I don't think there could be much of an inside
cone.
That filter should give you approx 352 square
inches of filter space. For a 13B at 7000 rpm K&N area
calculation says 53 sq inches is sufficient, so yes, I think I can safely say
you have more than enough filter area. So thats good as it will give more
filtering and less airflow obstruction.
I have to admit that I'm still having trouble with your
spreadsheet. When you calculate 53 sq inches using their formula,
this seems to indicate that you need 53 sq in of "filter element" surface
area. It looks like they're assuming all their filter elements
to be the same thickness by eliminating that parameter. From that
standpoint, I think you can drop the X4 factor to estimate the pleat
area, because they've already built that into their recommended area
formula.
If all we care about is the filter element surface
area, then your "filter area" (i15) seems to give the number we need to compare
to their formula. This would be assuming that you have one of their more
normal filters that doesn't have the end open.
Back to the filter I had mentioned, 4.5 base x 3.5 top
x 5.75 length. In their sizing info, it appears that they want you to
reduce the height by .75", because the ends of the filter are sealed in rubber,
and don't pass any air. That makes my example 5" tall. using those
numbers, I get 63 sq in for filter area. Since I will run 7500, that makes
the requirement 57 sq in, rather than 53. Sounds like it will still
work up to about 8200 rpm, which should be sufficient
:-)
Heck, I'll order one and see how it works. Easy
to test on the ground before going to the trouble of making a box
for it to live in.
Rusty (almost
deleted this since it was getting out of
control)
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