How I tested my fuel flow and get exact liter per hour.

[tryingbe]

I disconnected the return hose (hose that connects the regulator and the metal line) at the metal line, put an extension hose to reach to a container (used 1 gal oil bottle works great). I jumped the + end of the coil to get the fuel pump running, then time it for 1 minute then shut down the pump. I got about 3.4 qt in the container.

Using (3.4 x 60) / 4, I get the flow number for gallon per hour. Then using this awesome website, I get my liter per hour. http://www.convert-me.com/en/convert...llon_hour.html


My Walbro 255 HP fuel pump, with a 3 bar regulator, a big BOSCH fuel filter, and at 12.5V, flowed 193 lph. I'd imagine when the car is running at 13.5V, the fuel pump will flow a little more. Now, I know what HP my fuel system can support.


Do watch the container carefully, if it pass 2 qt while at the 30second mark, stop there, other wise, it'll over flow. Use this equation (QT x 120) / 4 instead if you use 30second instead of 1 minute.

Do be careful with the flammable gasoline, get it on the hot exhaust manifold and your car will burn down.

[contraption22]

You may want to do the test again with fuel pressure at full boost. If your base fuel pressure is 55, at 20psi of boost, your fuel pressure should be 75psi. Pump volume drops significantly as pressure increases.

[Vigo]

Yup. Sad to say, on a system with variable pressure, the reading at 55psi is almost useless.

[cordes]

Agreed. Crank the AFPR up to 90 and see what it is...

[Force Fed Mopar]

You can use a mighty vac to pressurize the regulator and maybe use a battery charger to keep the battery at full voltage while testing.

FYI the volume goes down as the pressure goes up. Or at least that's what every chart I've looked at seem to show.

[Vigo]

Yep. It's why carb cars are able to make a ton of power on some really shitty little fuel pumps pushing 6 psi.

[iTurbo]

Kudos for doing the test. Would like to know what you plan to do next as far as testing.

[zin]

To be fair and accurate, it should be at the proper voltage, it makes more of a difference than you'd ordinarily think. Though I get that, if you go by what it's capable of with the low voltage handicap, it will build in a safety margin, I just like to know exactly ...

On the up side, looks like the pump will deliver as advertised!

Mike

[tryingbe]

You may want to do the test again with fuel pressure at full boost. If your base fuel pressure is 55, at 20psi of boost, your fuel pressure should be 75psi. Pump volume drops significantly as pressure increases.

My base pressure is 3 bar. 43.5psi. Yes, fuel volume drops as fuel pressure raise, I am well aware of that. Once I have my base fuel volume number from my fuel pump at 43.5psi, there are enough fuel chart out there I can use to get a close idea what my fuel pump can flow, without testing my fuel pump at every psi.

Example, http://www.bmotorsports.com/shop/ima...pump-chart.gif

Yup. Sad to say, on a system with variable pressure, the reading at 55psi is almost useless.

My base pressure is 3 bar, 43.5psi. At 55psi, I would be 11.5psi in boost.

Agreed. Crank the AFPR up to 90 and see what it is...

My base pressure is 3 bar, 43.5psi. At 90 psi, I would be 46.5psi in boost. This ain't no diesel.
Though, if I have a fuel point at 43.5psi and one at 90psi, I can probably put both point on a chart and draw a linear line thru them and get all the pressure vs volume points I'd ever need...

To be fair and accurate, it should be at the proper voltage, it makes more of a difference than you'd ordinarily think. Though I get that, if you go by what it's capable of with the low voltage handicap, it will build in a safety margin, I just like to know exactly ...

On the up side, looks like the pump will deliver as advertised!

Mike

You're right, I wanted to know what my pump does at 12.5V on battery alone, worst case scenario.

[shackwrrr]

Yeah good to know what it will do at 12.5. Dont want to rely on the additional flow in case the belt flings off at WOT.

[Vigo]

True that. So 11.5 psi boost is max boost on your setup right now? If so sounds you have a lot of safety margin.