Originally Posted by Airboy
The Torque curve, as plotted against engine RPM, is not accurate in the sense that the engine is not actually at the RPM indicated on the chart but I wouldn't go as far as "artificially inflating..." That RPM scale is calculated from the roller speed. As soon as you step on the gas, the engine will speed up to the stall speed and the wheels has to "catch up". The calculated RPM will be less than the actual engine speed.
That being said, the torque curve, as shown, does give an indication of the acceleration that you would feel. Imagine if you were blindfolded and didn't know the car had an automatic, would it feel like a lot of "low end" torque?
I made some plots and stuff that covers this:
When going from slipping (under stall speed) to gripping (after stall speed) the torque is multiplied not due to an increase in torque output but it catching up and applying it all in a shorter amount of time. SEEMINGLY increasing torque output and greatly increasing a more immediate power output.
The dyno will show it in a torque spike. The driver feels it in a stronger launch. The torque output in actuality is not any higher.
The true reason a stall drops ET is due to getting you into your powerband immediately
...just like a clutch drop.