I was reading up on torque converters. They looked very bulky and heavy. I was thinking perhaps a torque converter could be made better if it was simply two turbines and a tube of varing x-sectional area. The idea is a small centrifugel turbine pumps fluid through a pipe with a very small cross sectional area. The fluid flows at a high velocity. The tube expands and the fluid moves slower but at higher pressures. This slow high pressure fluid spins another turbine of equal or greater size of the first turbine. The second, or output, turbine has more pressure behind it so it has more torque. Will this be better than a conventional torques converter? It would be lighter but the high speed fluid may cause resistance reducing efficiency. This could be reduced by giving the majority of the pipe a large x-sectional area, but that would would mean more weight from the extra metal needed to conatin those high pressures.