The pump may be rated for a given flow rate but it should be checked as
fitted to see how it actually delivers through however many feet of what
diameter hose, filter, regulator, needle valve, and the like. Check it
with a nearly empty tank in case the max flow is dependant on head
pressure. Their might be a bit of a loss from acceleration G forces too.
A few years back, a friend of mine was running a Formula B car on the
track we had setup on part of the old Stapleton Airport. There were some
long straights that allowed for long periods of full throttle. The Lotus
Twin-Cam was fitted with 2 X 45 DCOE's fed by a Facet pump that was rated
to supply more that the engine should ever be able to consume. Still
trying to get the jetting ideal, there was an oxygen sensor fitted in the
exhaust system to monitor the air / fuel ratio by interpreting the
readout from a digital multi-meter. He discovered that near the end of
the longest straight the engine lost power and the mixture was going very
lean. Closer observation of the meter showed that the engine was leaning
out for the last 1/4 of the straight. The problem was traced to the pump
not being able to keep the fuel bowls filled for that length of time.
None of the other tracks permitted the wide open throttle time so the
severity of the problem might not have been discovered.
Just 'cause it says it pumps X/Hr doesn't mean that's what is getting
there.
110 gallons per hour is almost 4 oz per second, if it all gets there it
should be more than enough, you'd hope! Just as long as there is enough
there when it's needed.
Bill
70 GT-6+
On Tue, 30 Oct 2001 18:12:45 -0700 (MST) Mark J Bradakis
<mjb@autox.team.net> writes:
> What kind of volume are we talking about?
>
>
> My Killer Spit, with an internally stock 1500 motor and two 40
> DCOEs, uses
> about 4 gallons per hour. It is pretty unlikely you'll be able to
> find an
> automotive fuel pump that won't be able to handle that sort of flow.
> The
> little Facet electric pump delivers about 12 to 15 gallons per hour,
> and it
> is one of the smaller capacity pumps on the market.
>
> My guess is that a full race two liter motor might have a capacity
> for 10
> to 12 gallons per hour. Hmm, I know there's a rule of thumb
> relating gallons
> per hour with horsepower. As I recall, top fuel dragsters have some
> rather
> interesting fuel flow requirements, with plumbing that looks more
> like dryer
> vent hose than fuel line - they don't need it for long, they just
> need it all
> at once!
>
> mjb.
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