Hydraulic pump as a dyno load

[WPH]

Any pointers at this direction? I'm thinking about using a rotating pump housing and a load cell to measure torque. Mostly for inline and flat 4 engines NA below 300bhp.

[Tony]

It should work, only problems might be cooling the oil. The temperature rise of oil will be very roughly double that of water, and where hot water can just be dumped, you need to cool and recover all that hot oil.

Only other complication I am aware of, might be reaction forces from the flexible hydraulic hoses. These will likely be running at very high oil pressure, and the hoses themselves will generate forces that may influence the measured torque reaction of the pump. There are ways around this, but recognizing the problem in the first place is half the battle.

If you already have a hydraulic pump, it is probably worth a try. If not, a suitably large and robust pump will certainly not come cheap.

I have seen this idea used successfully testing smaller outboard motors, and smaller air cooled engines, but never at anything like 300 Hp.

[WPH]

I managed to dig up some info about pump capacities needed,
minimum would be closer to 500-600 litres/minute@200bar pressure and the price is astronomical unless you can find a second hand unit.
Hydraulic fluid tank capacity would have to be bigger than 600litres and a cooling system capable loosing all the HP through the system.

Conclusion is for small motors only...