[rjahl]

Moving into a new PC today and while watching hard disks spin around, I started to take a better look at the Torque Converter Maps.

My understand may not be complete but the following are the torque converter closing maps for gear 1 and gear 2. There are opening maps as well. For clarity, I did not show them.

Notice how the TCC does not appear to close at all in 1st gear. It's not until 96% throttle that it starts to clamp down and a really low engine RPM.

Seems to me that this prohibits the TCC from multiplying torque under full throttle. Granted once the Turbine achieves its "stall speed" it pretty locked up anyways. From the maps, I am guess stall speed is around 2,500.

You see a similar trend in the other gears, the TCC locks up under full throttle.

Another surprise for me was the spread between the start and end of the closing. There is probably a map the quantifies what's happening in the middle of the spread but I have not seen it yet.

Another interesting tidbit, These maps hardly change between different engines on the E85. This along with most everything else I've seen in these files tells me BMW did very little to optimize the experience provided by the Automatic Transmissions. It's little wonder why so many people hate them.