HP required for the pump depends on the flow GPM and pressure PSI.Generaly the rule is the horsepower required is equal to GPM (flow) X PSI (pressure) divided by 1714 or GPM X PSI X .000583.So a 2500 PSI pump with a max flow rate of 15 GPM would rob about 22 HP if it was being used at full capacity.A typical plow pump would rob about 2 HP.Most central hydralic systems are open centre,and only draw power when in use,and when you actually move a lever.When you pull a lever the pump only draws the HP required to drive that actual device.You would only use a lot of HP if you tried to actuate everything in the truck at the same time.If you were actauting a plow,maybe 2-3 HP,where running a salter,with high conveyor and spinner speed,may draw as much as 15 HP.
[Edited by wyldman on 02-05-2001 at 10:48 AM]