DIY_EFI Digest V1 #241

[Todd Knighton]

Robert Van Zant wrote:
> 
> >The biggest problem with almost any dyno is getting rid of the heat
> >generated. For a 200HP engine, that's more than 500,000 BTU/hr.
> >That's enough to boil off 523lbs of water per hour, or 65 gallons.


We use a waterbrake type dyno to work with 600-700 hp turbocharged
engines.  Typically, for break in and light throttle calibrations, we
run the water in an closed configuration.. We have a 500gallon water
tank out side that feeds the pump and brake, then recirculates through a
radiator to the tank.
When power testing short runs can be done in this recirculating method,
but power testing engines at this level, not much beyond 30 sec. to 1
minute are done.  So cooling still is not a problem.
For extended runs, the system is open and the tank just drains, albeit
very rapidly at 75 gallons / min to dissapate this kind of power.  Then
refilled with cool water.
The water output from the dyno is regulated to be under 140-160 deg F,
if it is getting too hot, we open the output orifice and flow more water
with less pressure for the same power level and cool the brake better.

Todd Knighton
Protomotive Engineering