Flip through a Summit catalog or something... I'm sure there are mechanical
fuel pumps that will go well into that range. And why not? Stock big
blocks push out more than that... same idea, smaller pump housing.
If you're only looking to push 400 or so horses through this thing, a
mechanical is quite feasible and recommended. The electric system will work
as well, but will cost you a lot more, and for probably remote gains at
Just to temper JS's advice a wee bit..... if you opt for the mechanical
pump, choose it wisely. I have experienced fuel pump float at high rpm....
The pump lever can't follow the pump cam and fuel volume will go down. One
very good thing about mechanical pumps is that when the motor stops, the
pump stops. Electric pumps "should" have some kind of Murphy device to shut
them off in the abscence of oil pressure or rpm..... (think 'can't get out
of the wreck and the fuel pump is still running'....). I like the safety of
the mechanical pump but the consistency of a good electric is hard to
Yours is relatively mild compared to some of the grenades I've tried.....
and most of them lived quite well with mechanicals. Watch real close to see
if you're nosing over downtrack or through the traps.
. Electric pumps "should" have some kind of Murphy device to shut
A friend used to drive a Chevy Vega that had a fuel pump wired to run only
when there was oil pressure.
One day the wire from the oil pressure sending unit fell off.
The car ran until the carb was dry.
The car stopped.
The fuel pump would not run until oil pressure built.
oil pressure would not build until the engine fired.
Engine would not fire until the fuel pump ran.
Cars today use an inertial switch that cuts off the fuel pump if the car is
in a wreck.
Well, you're right and you're wrong..... Ford uses an inertia switch (not an
inertial switch) to cut fuel pump power. Other marques use various
strategies... oil pressure, ignition signal.... Lord knows what else. What
applies to one car doesn't necessarily apply to the one parked next to it.
The inertia switch requires a specific amount of force to activate..... I
can foresee the day where a mild accident breaches the fuel system but
doesn't trigger the inertia switch... the ambulance chasers wil have a field
day with this one.
I recall the Vega not-so-fondly..... aluminum block with cast iron linders
and a cast iron cylinder head to make sure the motor didn't leap out of the
engine bay. Every year or so we troop down to Circuit City or similar and
buy the latest greatest computer, all the while thinking that the "state of
the art" with autos has been stagnant for 50some years. Just when we think
we have seen it all, the engineers "improve" things.
Please, be sure of your facts before asserting a particular point.... I
would certainly be unhappy if I gave bad advice and the executor of their
will decided to make a test case out of the deal.
User installed, aftermarket pups are usually done with price in mind....
safety devices are often overlooked.....and, getting back to the initial
thrust of this thread - we ARE looking at a consumer installed, aftermarket
pump installation. Sadly, there is no inertial switch premounted with this
modification in mind....
You'll be surprised at how small of a fuel pump
you really need. It's all based on how much power you
expect to make, regardless of engine size, carb type,
cam specs, etc. A naturally aspirated motor only needs
.4 to .5 lb/hp/hr.
to the Aeromotive web site for an excellent tutorial
on selecting a fuel pump.
IMO, electric is clearly the best racing pump.
But for a fun street car, it's too expensive and too
complicated. A mechanical pump will work just as well
on the street for a third of the cost and a lot less
work to install properly.
Not really. As long as you set up your fuel
system correctly, whatever fuel isn't used will be
returned to the tank.
But if the pump is too big, it really just a
waste. Costs too much money, makes too much noise,
draws too much power, more difficult to mount, etc.
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