how to know how many gallons I am bleeding off???

Anyone tell me how to figure how many gallons I am bleeding off. Say I had a 14gpm pump and went to a 18 gallon pump. How can I get the fuel curve right down low where it was good before and use the pump on the other end.
I think my math is incorrect.
in other words, say before @ 3000 rpm I was using 67 main and 70 loop, now I have 1 gallon more at 3000 than before, etc etc... Thanks, I think my mind is messing with me.

 

All fluid flow calculators and programs use the same basic flow equation developed centuries ago using Bernoulli’s Principle:

GPM = Some Constant * Flow Area * Square Root of the Pressure Drop

Where:

GPM = is the calculated flow rate in GPM through each individual fuel nozzle or jet in the engine fuel system.

Some Constant = a function of the specific gravity of the fluid, flow coefficient of the orifice, and some math conversion constants to make the units of measurement all work together.

Flow Area = the flow area of the individual fuel nozzle or jet in the engine fuel system.

Square Root of the Pressure Drop = the GPM is a function of the Square Root of the Pressure Drop across the fuel nozzle or jet. The Pressure Drop is the difference between the upstream fuel pressure measured at the orifice and the pressure downstream after the orifice.

http://www.pumpcalcs.com/calculators/view/103/ is a link to an on-line orifice flow calculator that performs these calculations for a single orifice. The PumpCalcs website also includes great background information and sample calculations to help you use this basic orifice flow equation.

Patrick Hale
www.DragRacingPro.com

 

get yourself a davenport program..Dave

 

You need to figure what % of that 16gpm was going in the motor before. To do this find:

Total Nozzle Area (area of all your hat jets and port jets)=A

Total Return Area (area of your loop + main)=B

A/(A+B)=% going in the motor or
B/A+B)=% returning to the tank

So if you have say 65% going in the motor on your 14gpm pump, you have 9.1gpm going in the motor (.65 X 16)

9.1 on a 18gpm pump would mean 51 of available pump going in the motor (9.1/18)

Now here's your formula B=((A+B) x %returning to tank)

SOOooo B=49% of total area

the 49 comes from 100%-51%

Now you need to figure what loop and main would have a total area (B) of whatever 49% of your total area is (A).


This is all theoretical, but it will get you close. A program would make it much easier.

Josh

 

A program would be much easier that stuff will make my head hurt..lol.. But I will check it out. I am just trying to get a fuel curve similar to where I was with the old pump.

 

Im almost due for some more of the camaro's vids!!

Yup, jetsize is helpfull. Not that your performance doesnt speak for itself.

Let me know if you want a walk through with the program, probably 1/2 hr and you'll be in business

 

This might sound dumb, but cant you just place you fuel system on Spud Millars Calculator. That will show you the % differant between pumps.

 

Jet sizer

I have a Davenport jet sizer program I bought and never used , it is just for that you can set your old system up and change anything and it will tell you what you need to do to keep the fuel system the same to the engine. I think it will figure alt. changes for you too.
I will sale it
Billy
540 598 4949