Water Brake Engine Dyno

[Ayrton1]

Can someone help me?
I've been told that a water brake dyno is really just a impeller-type water pump on steriods. If this is true, approx. what whould the gpm and head pressure be, say for a 100 horse-power spark-i.c. engine?

Thank you for your time and response.

A.S.

 

[ChristopherFehr]

I gather you would like to build a dyno for measuring the power of your engine, possibly a car or motocycle? The calculations should be fairly simple if you can measure the flow and pressure for a pump discharge and factor in the pump efficiency and drive it all from the car or bike.

The formula would be BHP = (USGPM X TDH)/(3960 X Pump eff).

You may also want to make a correction for loss in the drive from your engine to the pump.

For 100 hp you would need approximatly 1000 gpm through 600 ft or 4" pipe! You may be able to find a more practical way of increasing the pressure the pump has to work against.