Why dual feed a p-pump?

mech2161 said:
Pressure at the other end may or may not be the same.

Fuel returning to the tank? How much fuel are you using?

It doesn't matter if it's a closed system or not. You will have harmonic vibrations in the fluid.
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how could it not be the same? newton says it is. if there is 50 psi at the inlet adn 50 psi at the reg how could there not be 50 psi everywheres inbetween? (or very very close). because those little plungers are gulping some up and spitting some back? i understand that this will create turbulance in there but i think there is already gonna be a bunch of that because we are pushing so much fuel thru there in the first place

no wheres near the supply volume - and i am gonna keep it thta way

"harmonic vibrations" ? are these vibrations gonna shake the fuel so hard that it shakes the air outta it? when its under 40 or 70 psi? can they vibrate the fuel away from the barrel? i dont see how they could...
 
the fuel once it passes thru the whole pump is also allot hotter so that in itself is enough reason to feed from both sides of the pump.
 
right

so that being said think about this for a minute: if you plumb from both ends and return out of one end how much fuel is moving past barrel #4?

returning out the middle i can tell you exactly how much...same as is moving past #3 (and the rest of them, minus any the first two take and send towards the inj)

*with an existing pump if you plumb from one end and return out of the other there is flow past all the barrels. the end furthest from the supply gets the hottest fuel but there is a fix for that too, put a larger pump in front of the thing and move more fuel thru it. or turn down the regulator pressure so more is returning to the tank. what ever it takes to get the movement of cool fuel past the barrels
 
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smokin06 said:
i understand

so feeding it from each end isnt gonna help but is it gonna hurt.
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returning from where? from up front? if thats what you mean i think it does both. helps put cool fuel to #1. thats for sure. but what about the barrels towards the rear of the pump? #3 4 and 5? how much fuel will be flowing by them? i understand westons point, that if the thing barely has enough lift pump infront of it the regulator is closed and nothing (or little) is being returned. in that condition i can see ea line feeding 3 barrels. but what if you do have a pump infront of it? or what if you have just a little more than is req and it is still returning some fuel at full load? whats getting hot then?

i have taken my supply line off my pump and activated the lift pump and can not picture all that fuel getting pushed towards the injectors at full load. but anyone that is seeing a pressure loss obviously is doing just that

how many see a pressure loss at full load?

and what are you using for a fuel system?

if i have to i will add another 200 gph pump when i put the 13mm pump on, and have one feed ea end of the pump, just have a hard time picturing it needing that much

don
 
thanks for the help, i am upgrading to a 13mm and have a big fass pump i was talking with weston about fueling from the regular fuel entry and fueling from where the return is now and having the return come out the front of the pump, didnt know if this would benefit me or not just figured that from the standard fuel input that by thie time the fuel got to the front barrel and plunger the fuel was pretty hot, by fueling from the front where the stock return line is would give cooler fuel to the front half of the pump and the return would be straight out the front. again thanks for the help i am trying to learn all this.
 
So is this a performance mod?Or more to help longevity?Sounds good to me.DTanklage are you a engineer?Cause they always make stuff sound good on paper,but never works the same in the real world.Just ribbin ya
 
DTanklage said:
returning from where? from up front? if thats what you mean i think it does both. helps put cool fuel to #1. thats for sure. but what about the barrels towards the rear of the pump? #3 4 and 5? how much fuel will be flowing by them? i understand westons point, that if the thing barely has enough lift pump infront of it the regulator is closed and nothing (or little) is being returned. in that condition i can see ea line feeding 3 barrels. but what if you do have a pump infront of it? or what if you have just a little more than is req and it is still returning some fuel at full load? whats getting hot then?

i have taken my supply line off my pump and activated the lift pump and can not picture all that fuel getting pushed towards the injectors at full load. but anyone that is seeing a pressure loss obviously is doing just that

how many see a pressure loss at full load?

and what are you using for a fuel system?

if i have to i will add another 200 gph pump when i put the 13mm pump on, and have one feed ea end of the pump, just have a hard time picturing it needing that much

don
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I go from 60 psi to anywere from 30 or less under full load usen aeromotive A1000 1/2 lines regulated on the return , I use the stock inlet and outlet holes is this normal?
 
Heck with my A1000 I go from 40 at idle to around 80-90 at full load. With boost referenced aeromotive regulator.
 
JamieWood said:
Heck with my A1000 I go from 40 at idle to around 80-90 at full load. With boost referenced aeromotive regulator.
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Thinking out loud here.... but wouldn't the increase in PSI equate to a reduction in recycle flow (cooling)? As compared to maintaning a straight 40 PSI across the board? Or does it not matter due to the increased overall consumption of fuel at load....

:aiwebs_019:
 
yeah, maybe, but i would want the fuel there at full load

orig plumbed mine that way but then i took the reg apart and saw how thin the diaphram is

prolly was not designed to see 60 psi, but more like 10 or 20

if you rupture the diaphram raw fuel gets pumped into the intake manifold and can ruin the motor

compare the afc diaphram to the one in the aeromotive reg
 
DTanklage said:
if you rupture the diaphram raw fuel gets pumped into the intake manifold and can ruin the motor
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LOL, can you say RUNAWAY!!! Better hope ya got an air shutoff when that happens or its going to be a nasty and expensive death of that engine :rockwoot:



The point about raising pressure was good. Increasing the pressure with boost would also mean less flow across the pump, which means hotter fuel for the front plungers.

But i guess that would also be dependant on the pump you are using, if its flow rate drops drastically as the pressure increases you will have this issue, but if the pump is able to hold its flowrate at those pressures, than the increase of pressure is not going to change the flowrate through the pump a whole lot.
 
DTanklage said:
yeah, maybe, but i would want the fuel there at full load

orig plumbed mine that way but then i took the reg apart and saw how thin the diaphram is

prolly was not designed to see 60 psi, but more like 10 or 20
if you rupture the diaphram raw fuel gets pumped into the intake manifold and can ruin the motor

compare the afc diaphram to the one in the aeromotive reg
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Not the A1000 regulator has a base pressure rating of 40-75psi. This is originally designed for fuel injection. The regs. you are thinking of is for carburetor applications. These are perfectly fine at these pressures.
 
but wouldn't the increase in PSI equate to a reduction in recycle flow (cooling)? As compared to maintaning a straight 40 PSI across the board? Or does it not matter due to the increased overall consumption of fuel at load....
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yes to the first.

Even if you maintained a constant 40psi the return flow rate would decrease to compensate for the decreased pressure drop through the IP at WOT conditions
 
JamieWood said:
Not

the A1000 regulator has a base pressure rating of 40-75psi.

This is originally designed for fuel injection. The regs. you are thinking of is for carburetor applications.

These are perfectly fine at these pressures.
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how many fuel inj gassers you know of running 60 psi of boost?
 
DTanklage said:
how many fuel inj gassers you know of running 60 psi of boost?
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There are starting to be more out there than you think. When we went to Union Grove there was a 67 Camaro with twin turbos, compunded on a 540 and he said he was making 80psi. He didn't say what hp but the car ran a 8.xx and broke before the big end.
 
My buddy is putting together a 502 Big Block with twin 81mm turbos on it as we speak.
Its in a late 70s Nova 2 door.

Its in the paint shop now.
 
geez

was not talking about gassers

was talking about how the aeromotive reg was prolly not designed to see 60 psi of boost

more like 10 or 20

look at the diaphram in your afc and compare it to whats inside the reg

thats what i did...then i removed the line for boost ref
 
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