Randall,
You're thinking of inches of mercury, multiply by 13.6 to get inches of
H2O, so 28 in.H2O = 2 in.Hg.
I was just demonstrating differing pressure differentials to a customer
while flowing his head.
As you increase the press. differential you reach a point where the air
goes much more turbulent and starts to separate from the port wall,
usually
in the short turn, if you can minimize this turbulence you can acheive
more airflow.
I often test with and without a manifold or header and sometimes rig up a
fixture to test a manifold by itself.
Ron Meek
On Tue, 30 Nov 2004 16:13:46 -0800 "Randall Young"
<ryoung@navcomtech.com> writes:
> > I recently flowed an new stock1.0 inch manifold, 28" of water,
> manifold
> > only, #3 port only, 85cfm.
> > I also flowed a 1.25 under the same conditions, 105cfm.
>
> Pardon my ignorance, but why would you use such high pressure
> differentials
> to flow a head ? Wouldn't just a few inches of water be more
> similar to
> actual conditions ?
>
> Seems like you'd want the valve in there too ?
>
> Randall
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