TDIwyse wrote:
All in all it seems like the material composition of the stator should be suitable for use in an automotive application as I don't think there's many situations where it would exceed 500 F.
At the risk of sounding sarcastic, "Gee I would hope so." Seriously though, it is relatively easy to reach those temperatures or higher. All it takes is a dedicated will to destroy your transmission. No you can't get much past 260°F in heavy usage without the transmission trying to protect itself. And no I will not tell you how to do it, but I've seen torque converters with blue shells. Blueing of steel usually only happens on polished chrome exhaust pipes. But IMO, if you don't break a few, you haven't tested them right.
I spelled it out to the torque converter group in 2004. "There's far more torque per cylinder than the Hemi. It's gonna need a stronger damper." Their solution years later was to instead, lower the engine torque. I directly asked that senior manager for a refund of that percentage of my vehicle cost. My answer was a not so nice stare. (Yes I'm career limited - guess why.)
Bottoming out the damper changes the already high transient loading of a 4 cylinder diesel (torsional vibration) into an impact event. For instance, a steady state (read average over time) torque of 300 lbf-ft can have transient torque (noise on the signal) from 250 to 350 lbf-ft. That's with a spring (the damper) holding back the worst of the highs and returning it's energy in the lows. Bottoming out the spring and slapping metal against metal could easily double the magnitude of that noise resulting in asking the clutch to hold anywhere from 200 to 400 lbf-ft. (not the real numbers just an example) Along comes another engineer who hasn't been told the whole story and his manager asks him to design a clutch that holds 300 lbf-ft. He bakes in a little cushion and makes it good to 350. It works. For a while. Then the springs in the damper take a set (permanently deform) and the damper starts to bottom out. Now that 300 lbf-ft clutch that can actually hold 350 has to hold 400 and fails. Is it the clutch engineer's fault?
I have no idea if that's what happened or not. It's my opinion based on my observations. Others certainly saw that part of history differently.