[C3H8]

couple of misconceptions, here.

a power steering rack with fluid in it is no more difficult to turn then a manual steering rack, assuming both have the same reduction ratio. well it may be ever so slightly more difficult to turn, but this extra resistance is almost not perceptible.

let me explain this before ya all judge and say i am full of it...

want proof? take a typical car equipped with power steering and jack the car up so the front tyres are COMPLETELY off the ground. with the engine off, climb in and turn the steering wheel left and right. with the tyres off the ground you have eliminated the resistance between the road and the tyres and you are ONLY feeling the drag in the actual steering system. its nearly effortless in spite of the power steering rack having fluid in it. this is because it only moves a very small amount of fluid. i have measured a 1998 honda civic's fluid pumping capacity of the power steering rack and it moves about 3 ounces from the centre steering wheel position to full left OR right lock, and about 6 ounces total if you turn the steering wheel from full lock to full lock. 6 ounces? that's nothing! power steering fluid is super thin. it is usually about as thin as atf. atf is ROUGHLY as thin as a 5w20 motor oil. i have tried this test on a few cars and in all cases it takes no effort at all to turn the steering wheel with the tyres off the ground.

this tells me and it should also tell you that a power steering rack that is full of fluid has about the same drag as a purely manual steering rack. even with the engine off! if you empty the rack of fluid it should decrease the steering effort, but the decrease is again so small you probably won't be able to notice it! so you might as well make a loop from the inlet to the return and keep it full of fluid so the hydraulic portion of the rack stay's well lubed and sealed from dirt and water. this is also a good time to clean the outside of the rack and inspect it for wear, or cracked/ripped rubber steering bellows. also might as well grease the snot out of the mechanical portion of the rack. I have found that by greasing the geared section as well as the teeth on the inside part of the inner tie rod end, you can usually cut down on the effort it takes to turn the steering wheel. most racks, power steering or manual come from the factory with very little grease in them. i even go so far as to drill and tap a ZERK grease fitting into the centre portion of the rack where the mechanical parts (not the hydraulics) are.

why is it that a hydraulic rack has nearly the same resistance as a manual rack? it is because the power steering rack has some 1 way valves inside the hydraulic part. each time you turn the steering wheel left, or right, the rack pumps fluid around the entire power steering system. it pulls fluid from the high pressure hose and pumps it into the low pressure return hose when the engine is OFF. because the power steering rack is composed of 1 way valves and is not a centrifugal pump but more akin to a hand operated bicycle tire inflation pump (with those 1 way valves) , there is very little resistance from the hydraulic portion of the system.

the only reason a power steering rack ever has more steering resistance then its manual counterpart is because nearly all power steering racks have a lower gear ratio to make steering quicker then their un powered manual counterparts. this extra gear ratio is like you using the transmission in the car to take off in second gear instead of first. both items take more effort, but the result is higher speed for the trans, and quicker turns for the power steering rack.

my stratus power steering works beautifully to me, but it takes a lot of power. when at a stop and i turn the steering wheel i can see the load % on my obd2 scanner jump up a bit. my engine's rpm also drops by about 200 rpm because my idle speed controller is currently disconnected. if i take the belt off i gain about 2.5 mpg in city driving. and about 1.5 in the highway. my engine bay is absolutely starved for room being a v6 with manumatic 4 speed trans and lock up torque converter. i am planning on removing my power steering pump and installing a toyota mr2 electric pump as well as the mr2's electric steering control system and computer. i am going to use a ford starter relay together with an on-off switch to manually turn the electric power steering off at speeds over 15mph, so that there is no electrical load at all during those times. and the only time my electric steering will be on is if i am under 15mph AND i have the switch set to on. under this situation the stock toyota mr2 steering control computer and system will govern the electric pump.

i would go without power steering entirely but my car has 215mm wide tyres and it weighs about 3000lb empty so the steering effort is skyscrapers above that of a manual steering civic or merto.