QUOTE(Dr Evil @ May 24 2014, 05:30 PM)
Interesting. I built the tranz in that car and the new owner contacted me to discuss the possibility of putting even more HP and TQ into it. I told him to ditch the 901.
Understand the torque is how much instant force is applied. Like a slow moving truck, it can pull a stump out at a slow pace. Resisting torque takes beefy gears, like the ones in a 930. The 901 gears are thin, this is fine for high RPM with low mass. Not so fine for torque when your beefy engine says "MOVE!" and your beefy tires say "GRIPPING!" and inertia says "HAHA FUCK YOU!" and you rip the thin teeth off of the gears.
I never understand why people would not put money into an appropriate transmission to use ALL of the power available. However, I think that V8 conversions are not practical to begin with. Kind of like a hot rod rather than a performance vehicle unless done right with lots of money.
mike I think another point of the weakness is the size of the input and output shafts and the distance of the supporting bearings through out the tranny.
from the clutch into the tranny is one shaft that is only held in place by 2 bearings, and the distance between the two spans along the differential and the gear stack to the "intermediate plate" which is the last bearing that offers any support to the shaft. all the torque input is carried on this shaft and it is not of sufficient size to not twist and deflect [candy caning]. when this happens bearings and gears go bye bye.
the next weakness would be the output shaft at the pinion gear and the ring gear. the pinion end could simply twist right off. the shaft size is small there also.
I have sheared pinions with much larger shafts than on a 901.
so the 901 will live when not abused with clutch dumping launches, burn outs, hard "speed shifts".