One of the Velocity builders with a Soob (Wayne –
something) said he had so much foam returning to the sump tank from the
pressure regulator that the foam would come out of the fuel system vent.
He added a small reservoir of some kind in the vent line as a foam/liquid
separator. That apparently solved his problem.
In the 4-5 hours of
running time I have on my 20B I have not observed any foam from the stock venting;
nor have I heard of anyone else observing this phenomenon. Why in one
case, I have no idea. But the potential for foam buildup is there, and it
is something to keep in mind when designing your fuel system.
Al
While
running my ground testing, during the winters using auto
fuel.
I used clear 3/8" tubing for fuel line, from my Facet
pump
up to my carburetor.
While
the engine was producing power, I noticed bubbles in the
line,
on the pressure side. Baffeled by how air could be
leaking
into
a six psi line, I looked it over, and discovered that there
was
a slight kink in the tubing. The bubbles were from the
small
restriction in the pressure line (come to think of it, it
may
have been a three psi pump, not six).
Anyway,
the bubbles really don't bother the Carter carb, with
a
float, but, I wonder how much vapor bubbles are returned
from
the EFI pressure regulator. It seems likely, that with
a
35 psi pressure drop, the vapor may be very significant.
Certainly,
someone on this list must have a setup capable of
testing
the theory. All one would need would be a clear vessel
to
return the fuel to, and perhaps suck fuel out of, with the
remaining
system intact. Pump on, engine off would seem the
worst
case. Cold weather auto fuel would be the most likely
to
vaporize.
Test
results could contribute to safe fuel system design.
George
Graham
Mazda
Rx7ez N4449E
Homepage
<http://bfn.org/~ca266>
__________________________________________________
Do
You Yahoo!?
Tired
of spam? Yahoo! Mail has the best spam protection around
http://mail.yahoo.com
>>
Homepage: http://www.flyrotary.com/
>>
Archive: http://lancaironline.net/lists/flyrotary/List.html