I have a LUK gear driven pump with no vacuum on my Fummins. I had to shim the valve on it so much that It has almost no assist at idle just so it would play nice witht he Ford Hydroboost. That pump puts out crazy pressure but I think the flow rate is low. I cant figure it out, the pump is louder (in the truck) than the 12v itself.
I will do some digging I have the pressures and flow rate here some where, oh here they are.
163BAR equals 2364.115 psi. I had my LUK pump reset at a local hydraulic shop that specializes in truck power steering boxes. cost me $45 to add the right shims and test for max pressure and flow(gpm). my pump stock had 2250 psi and 4.25 gpm. the pressure valve looks exactly like the one in a GM saginaw pump. you can do it your self, pull the valve out of the LUK pump, unscrew the hex ( it has a small screen in it) on the end of the valve and add 2 or3 shims along with the shims already there (if any)(he took the shims out of an old saginaw pump) ,do not loose the small ball or spring. reinstall the valve and test the pressure, I think he used 3 shims on my pump. it tested at 1650 psi. and 4.25 gpm. saginaw gear boxes and hydroboost can use up to 1800 psi. I talked to LEE Powersteering in LA. they build nascar gear boxes , pumps, and high performance off road stuff, and that`s what they told me . 1800 is max but set it to 1650 or so. put a "T" in the out let of the pump and put a high pressure gauge ( high side from an oxygen welding regulator) and with the engine running, turn the steering wheel all the way to right or left and read the pressure gauge. do not hold the wheel too long, 2 or 3 seconds will give max pressure on the gauge. after I saw how he did it, I know how to adjust the pressure in any saginaw or LUK pump. hope this helps capable people to adjust their own pumps. add shims to LOWER pressure, REMOVE shims to raise psi. changing the pressure will not change flow (gpm) LEE told me hydroboost systems can use up to 4.5 gpm. most stock pumps put out about 1200 psi more ore less