fuel pumps...

How many horsepower will a high performance mechanical fuel pump on a 302 support? Would it be better to use an electric pump? Application is
for a crate 302 FRPP 345 HP motor with a 625cfm Grant Road Demon through Heddman shorties and a Flowmaster dual series 30 & "H" pipe American thunder system.
JD
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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 best.
JS

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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 ignore.
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.

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. 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. Etc.
Cars today use an inertial switch that cuts off the fuel pump if the car is in a wreck.
Erich
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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....

out
is
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On Fri, 31 Dec 2004 07:59:45 +0000, Jim Warman rearranged some electrons to form:

My sister used to have one years ago, if I recall correctly, she hit a small animal and it ripped the whole front suspension out of that so-called car.
--
David M (dmacchiarolo)
http://home.triad.rr.com/redsled
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Jeff Davison wrote:

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. go here: http://216.242.145.16/products/content_p.phtml?pk  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.
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.boB
1997 HD FXDWG - Turbocharged!
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Is there ever a risk of oversizing the pump?
Jack
.boB wrote:

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Jack wrote:

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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.boB
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