Fuel Flow Test

[craigg]

Barry Grant Fuel flow test for a 1 gal can in so many seconds.

Any thoughts about how the fuel flow test would equate to a low 10 second car on E-85 = how many seconds to fill the 1 gallon can?

Thanks, Craig

[adamsvega]

a low ten second car at 2300# needs way less than one at 3650#
need an et slip or h/p number to be acurate .you can always use 40% more than gas to be safe .albite its alot less than that .

[craigg]

3400# plus
Thanks, Craig

[revvedup]

Not sure if this helps or not;

A good rule of thumb for gasoline is to multiply hp requirements by .17, while E85 is .23

Example - 500(hp) x .17(gas) = 85gph
- 500(hp) x .23(E85) = 115gph

Now for the more important considerations - Keep in mind the weight of the fuel in the fuel lines, where the pump is located, how many g's the car launches at, and the size of the fuel line.

For example - gasoline weighs about 6.073 lbs/gallon
- E85 weighs between 7.46 and 7.56 lbs/gallon

Typically, a fuel pump pushing up to 175gph only does so at 16lbs of pressure.

If your fuel pump is located in the rear, it puts out 16psi, you are running E85, and your car launches at 1.0g, the actual pressure moving forward to the engine is about 8.44lbs.

In order to have a pump that puts out a usable pressure to overcome the g's on launch, the volume is increased, as well. It is much better to have a fuel pump that puts out more volume than necessary, in order to maintain constant pressure to overcome the fuel traveling rearward in the fuel line.

That is one of the reasons you see 300+gph fuel pumps on cars that would not seem to need it in the first place. A street car can easily get by with a smaller pump, because it is not being subjected to the launch forces of a drag car.

If I am planning a fuel pump, I figure out how hard the car launches, multiply that by the fuel I am using in weight, and buy a fuel pump that can overcome that pressure. It is not hard to exceed 1.5g's in a 10-second drag car, so if you do the math, it is really evident how little the fuel pressure is on the launch. It is better to have more than not enough. 26+psi pumps overcome those forces easily, but at a higher cost, and require a return system either at the pump, or regulator.

That is my spin on it.