I can definitely see why they would cost more…. What I don't understand is while cruzing down the road the turbo rotor speed is probably 15-30K rpm (no load). In an H1C the hydrodynamic bearing system achieves stability at a much lower rpm if it is properly balanced. With the hydrodynamic bearing system the bronze bearings are rotating ½ the rotor speed after stability and again.. Assuming proper balancing… the bronze bearings are neither in contact with the bearing housing bore nor the rotor shaft journal diameters from approximately 15K to 100K+ rpm. How could a hydrodynamic bearing system have higher friction than a contact bearing system?
Now if the rotor system does not posses the proper stiffness in a hydro bearing system and starts to bend which occurs way after initial bearing stability but at much high rotor speeds (primary contributor are compressor wheel size & amount of unbalance with respect to journal diameter) then I could see where this could be a possible solution.
I do believe they solved a problem. The ultimate question is what was the problem they were trying solve?
