xoxbxfx
Founding Member
of course there is a reason... its a PITA
I Agree though, a mech pump is much easier and can flow what he wants.Fuel Pump ?'s How many GPH?
- Thread starter bad68coupe
- Start date
of course there is a reason... its a PITA
I Agree though, a mech pump is much easier and can flow what he wants.
302 coupe
Founding Member
a stock replacement mechanical pump would work fine for him, as would the stock 5/16 fuel line. No reason to upgrade at the current level unless its for braggin' rights.
Alright, Alright, Alright, ya'll have com very close to talking me into it. I think i am just going to go with a mechanical. But one more question, where does the filter go?
As far as the switch for the electric pump goes, couldn't it just start up when i turn the key to accessory?
And im not racing, there was some guy in here talking about an emergency shutoff switch and all other kinds of doo-dads, is that necessary for the street?
As far as the switch for the electric pump goes, couldn't it just start up when i turn the key to accessory?
And im not racing, there was some guy in here talking about an emergency shutoff switch and all other kinds of doo-dads, is that necessary for the street?
With a mech pump, the filter goes between the pump and carb. But I also like to run a filter before the pump too, unless it causes problems (some pumps do OK with em, some don't) Can't have enough filters, dirt is the #1 cause of carb problems. With an electric, the pump needs to turn on with the ignition. An Emergency kill is a must, not just for racing. They're just as needed on the street, if not more than racing. When you get into a wreck and you're incapacitated, strapped or trapped in the car, you really want an electric pump still supplying fuel ?
Nothing that's been suggested here in an electric pump system could or should be called a "Doo-Dad" 
Even with a low pressure pump, you still need a regulator, run it without one and you'll likely have problems. With a carb, the fuel pressure is only there to push down the float in the fuel bowl to lift the needle off the seat,and let fuel flow into the bowl(s) it takes very little pressure to accomplish this function. Too much pressure and you flood the carb, eventually dumping fuel either into the carb throats (marine carbs are designed to do this) or all over the top of the engine.
With a mech pump, the filter goes between the pump and carb. But I also like to run a filter before the pump too, unless it causes problems (some pumps do OK with em, some don't) Can't have enough filters, dirt is the #1 cause of carb problems. With an electric, the pump needs to turn on with the ignition. An Emergency kill is a must, not just for racing. They're just as needed on the street, if not more than racing. When you get into a wreck and you're incapacitated, strapped or trapped in the car, you really want an electric pump still supplying fuel ?
You're right "Doo-dads" was not the right word but i was intimidated when i saw:
"Use an inertia cutoff switch or plumb the fuel pump relay thru the oil pressure switch (ie zero oil pressure turns off the fuel pump - you will need a jump switch to bypass this for startup)"
That made it sound terribly dificult.
Iamdiffrnt
Member
An inertia switch isn't difficult, same thing they have on all new cars, hit a bump too hard the fuel pump shuts off till you push the button to reset it. Two wires, just hook it in between ignition and pump. The big problem is finding a convenient place to mount it. 
Ron Francis Wire Works has them, i'm sure others do also, or you could just grab one from the pick and pull.
Ron Francis Wire Works has them, i'm sure others do also, or you could just grab one from the pick and pull.
69gmachine
Member
Inertia switches are also directional; you should mount at least one longitudinally and one laterally (for side impacts). If you decide to gamble with your life and only want to install one, I'd recommend that you mount it longitudinally near the rear bumper, to protect from a rear end collision. I only say this because you have more control over your fate with a front end collision than a rear one, and I'm not going to assume that there will be enough force to disengage the switch at the opposite end of impact.
Mechanical is sooo much easier and safer. Use the inexpensive street/strip Carter pump, and you can upgrade it to support over 700 HP should you ever desire. They're rebuildable, so it will last for the life of the car.
Mechanical is sooo much easier and safer. Use the inexpensive street/strip Carter pump, and you can upgrade it to support over 700 HP should you ever desire. They're rebuildable, so it will last for the life of the car.
thehueypilot
Active Member
Basic formula for determing GPH for fuel pump = BSFC (brake specific fuel consumption) 0.4 (N/A carb) X 300 HP (HP @ flywheel) = 120 lbs/hr
120 / 6.2 (one lbs of gas) = 19 gal/hr
120 / 6.2 (one lbs of gas) = 19 gal/hr
Works like this: Car impacts brick wall (or other immovable object) Engine stalls. 
Fuel pump also quits pumping do to the lack of force driving the pump lever (commonly called a fuel pump eccentric mounted on the front of thecamshaft):SNSign:
I don't follow, from what i typed i derived: BSFC * .4 * HP = X lbs/hr
and then .4/6.2 (Don't know where these numbers came from.
I understand that you take your lbs/hr and multiply that by gal/lb, is that what the .4/6.2 stands for?
thehueypilot
Active Member
Sorry that was a typo it should of been 120/6.2 to convert to 19 gal/hr. I run a Carter "black" electric fuel pump in my race car and it has about 700 HP at the flywheel so a 100 gph fuel pump is plenty for my combo.
fasttback
New Member
brianj5600
Active Member
I believe NASCAR uses them up to 9000+ rpms. There is no way I would put an electric on unless it was needed.
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