The Stage III you have was lined with Kevlar where most just go with the high carbon material. You have your choice on which to use with the Stage III. With 2 race seasons under the belt of one of the Stage III high carbon units in a 700 rwhp vehicle it is still going strong with no signs of wear. We even had it restalled at a much higher rpm for the new 4V application. What we ran into was the 4V didn't produce the needed bottom end torque needed to get the revs up quickly and so the 0 - 60 ft times dropped slightly. After raising the stall speed again it made no difference with the short times. After some considerable thought we figured out that the extra weight of this TC was our culprit. During the past couple years my other TC builder has been developing and testing his multi disc. He's got it out in a few race cars and we have it going in a couple of ours now.
The Stage III weighs in at 44 lbs due to it's massive 11" billet lockup piston and cover. Where as the Stage IV weighs 37 lbs and is even lighter than the PI TD. The Stage III has 42 sq in of friction material compared to 100 sq inches for the Stage IV. The PI TD comes in at 39 sq in by the way.
It uses a flanged hub for the pump drive, this is basically a balloon plate for the Trans side. Similar to the Stage III and uses the same Stage III turbine hub and tower for the input spline, a very stout piece.
