"Actually if anybody is interested in how a Torque Converter works you can see some repudable articles here. They are very hard things to explain, they act as a fluid coupling that based on the rate of flow can multiply TQ for short periods depending on how quickly it exits the strator.
http://www.converter.cc/tech_talk/tech_main.htm
http://www.converter.com/torqueration.htm
http://auto.howstuffworks.com/torque-converter.htm
Typically it's a trade off, Tq multiplication for efficiency. I had a dyno graph somewhere of a tq spike through an unlocked converter, it can jump quite high depending on the converter."
"Yeah just remember a TC is a centrifugal pump, it is never a 1-1 input (like a clutch) until the converter lockup occurs (if it has a lockup clutch). At WOT a converter should never lockup unless you have a multidisk converter which can hold the power your throwing at it.
Maybe a way to explain it is if you spin a bucket of water around, the farther away from your arm (outer diameter) the more kinetic energy is being applied, and it's that momentum of kinetic energy that spins the tranny input harder than the input from the motor. The motor and the converter never spin 1-1 until it locks up. A high stall converter slips for performance reasons because the more power/tq at a higher rpm rule still applies, and in combination with a STR of say 2.5 you are effectively mulitplyng the torque at the given rpm more than twice what the motor is generating.
As an example, say if my car makes 350 rwt at 4000 and I have a 4000 rpm TC w/ a 2.0 STR, at a flash stall on the line the car will lay down approx 700 rwt for only but a few second, then it will gradually tail off as you pass the 1000ft mark. I will ask my tuner for any dyno graphs that he may have showing an unlocked car on the dyno. The spike itself since it is something that happens at low speeds is hard to reproduce on the dyno, but in many real aggressive car's (3 or 2 speed, non-lockup) you can see the TQ line WAY over the HP at the start of the pull and not pan out till the 5200rpm mark."
