Yup, and the more I contemplate the power update for myAMX and as gas prices seatdily rise the more I think about incorporating modern developments into my ride... Steve > So, if power assist is the name of the game then big pulley- small swept > volume would be the best combo for reducing parasitic loss. Yes? I suspect that if you simply under-drive the pump, at low enough pump speed the power steering could get "jerky", the assist might vary with engine speed, that would become Very Annoying. Truly variable assist you could probably do with an electric motor driving the pump instead of the crankshaft, which when you think about it is a 1920 buggy whip way to do it. You can argue that say water pumps, at higher revs you want more cooling, but power steering and A/C it's silly to belt-drive them. Oil ought to be electric drive, I think reliability and cost is the reason it's stayed mechanical (two stone-stupid gears). I often fantasize about making a motor where the front of the crank (balancer end) is nothing but a multi-KW alternator/starter motor and everything (oil, water pumps, valve actuation) is electric, with electric-drive servo steering. This last is happening now, and electric water and oil is used on various race cars. Make that alternator a big enough motor with a funny coupling and you'd have a hybrid.