Why dual feed a p-pump?

mech2161

mech2161

I have a secret.
Joined
Jan 15, 2007
Messages
3,986
If you look at the picture below, the fuel in the P7100 (left) has to flow past every plunger. In the P8600 (right) the fuel flows through a rail to each plunger. In each there will be pulses in the fuel flow. Less in the P8600. By dual feeding the P7100 it will help to reduce the pulses, equalize the pressure and give a more even amount of fuel to each cylinder. Temperature and fuel density are also effected with the dual feed.

This is just my opinion.

8.jpg
 
It will never work...the fuel will just flow in and right back out the OFV...

j/k I dunno if it make any difference or not, but for the time it took, and the cost of materials, the thought that I am providing cool fuel more evenly to the plungers makes it worth it for me.
 
how much would it cost you to switch it around so that both feeds go to the front and the return comes out of the back?

and mech, why will there be "pulses in fuel flow"? my supply line contains a steady stream of fuel
 
Pulses start at the injectors and/or barrells as they open and close and work their way back through the system...it's been discussed extensively here.
 
Last edited:
with 200 gph flowing thru my pump around the barrels will these pulses be measureable within the pump body, on the 'body' side of the barrels?

i could see major pulses with the stock mech lift pump but can not picture it with a electric that is moving so much fuel
 
The best way to feed it would be at opposite ends and return in the middle. Since that isn't possible the next best would be to feed both sides and return out the end.
 
DTanklage said:
with 200 gph flowing thru my pump around the barrels will these pulses be measureable within the pump body, on the 'body' side of the barrels?
Click to expand...

People that know more than I do say yes.
You can also get into it about pulses in the airstream, tuned runner intakes, etc.

Personally...I don't think we're at the point with this stuff to worry about the thousandths of a second on the track addressing those issues might gain. This ain't Pro Stock. LOL
 
mech2161 said:
The best way to feed it would be at opposite ends and return in the middle. Since that isn't possible the next best would be to feed both sides and return out the end.
Click to expand...

You're about to get disagreed with. LOL
 
DTanklage said:
with 200 gph flowing thru my pump around the barrels will these pulses be measureable within the pump body, on the 'body' side of the barrels?
Click to expand...

Yes, as each barrel takes in fuel it causes a pressure drop. When it closes it will cause a pressure spike. This is the pulse the system sees multiplied by six different events. Larger injectors, more fuel flow, larger pulses.
 
mech2161 said:
the next best would be to feed both sides and return out the end.
Click to expand...

with a stock pump body like my tow vehicle has i think one would be better off putting both inlets at one end and returning out of the other
 
mech2161 said:
Yes, as each barrel takes in fuel it causes a pressure drop. When it closes it will cause a pressure spike. This is the pulse the system sees multiplied by six different events. Larger injectors, more fuel flow, larger pulses.
Click to expand...

okay, there are measurable pulses within this 200 gph flowing thru

how do these affect anything we are talking about?
 
DTanklage said:
with a stock pump body like my tow vehicle has i think one would be better off putting both inlets at one end and returning out of the other
Click to expand...

You will have good constant pressure at one end. By the time the fuel hits the return at the other end it's like a swimming pool and a 500lb person just jumped off the high dive.
 
DTanklage said:
okay, there are measurable pulses within this 200 gph flowing thru

how do these affect anything we are talking about?
Click to expand...

A constant even pressure and volumn to each plunger. Equal amounts of fuel to each injector.
 
Not to mention the pulse that comes from the injection event ending.
 

Attachments

  • Port_HelixPlunger.jpg
    Port_HelixPlunger.jpg
    64.8 KB · Views: 140
mech2161 said:
You will have good constant pressure at one end.

By the time the fuel hits the return at the other end it's like a swimming pool and a 500lb person just jumped off the high dive.
Click to expand...

so you are saying the pressure is different at the other end?


and maybe you can answer my question from the other thread:

DTanklage said:
with a 150 gph pump do you think at full load the regulator is closed and there is no fuel returning to the tank?

how about with two 200 gph pumps?

(or a big belt driven mechanical)
Click to expand...
 
mech2161 said:
The best way to feed it would be at opposite ends and return in the middle. Since that isn't possible....

(then from later in the thread: A constant even pressure and volumn to each plunger. Equal amounts of fuel to each injector.
Click to expand...

it is possible, and i am going to do just that

and that is what i hope to achieve by doing so


oh, and i'll keep enough pump in front of it so that the regulator is still returning fuel to the tank, even at full load...

(for cooling)
 
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.
 
You must log in or register to reply here.
Back
Top