if that didn't help, a stall converter is like your clutch (for explanation purposes, just assume it is). I higher stall "waits" and links your wheels to the motor at a higher rpm, so you can launch at a higher rpm. it's similar to letting a clutch out at 2000 rpm (stock) vs. at 3500 rpm (aftermarket stall), but on an auto. it's also the thing that always breaks in auto trannies (or at least with my luck, they do). you'll notice that your car will rev to 17-1800 (I think, stock) or so rpm when you launch hard from a light- this is because of the stall conv.

 

Ahhh i got ya, so its basically just for your start and a harder launch correct