Originally Posted by juld0zer

Thread revival!

You're pretty much on the mark.
Here are the sensors that make it happen:
1- Clutch pedal sensor (the same one that allows you to start the car, ie. detect pedal is fully depressed)
2- Crank angle sensor (on the bell housing)
3- Neutral position sensor/gear lever position sensor
4- Input speed sensor (on the rear left hand side of the gearbox. Not far from the reverse sensor)
5- rear wheel speed sensors (on the diff). This one i'm not 100% sure about as #4 should suffice for smooth shifting.

1 tells the system to wake up
3 tells the system what gear you are currently in & what gear you are entering
4 tells the system how fast the (output i think) shaft in the gearbox is rotating. Automatic gearboxes use an input speed sensor for the same purpose - to enable smooth shifting.
2 is obvious - i tells the system what RPM the engine is rotating at and the system calculates the target engine speed based on the signal from #4 and #3.

Since the ECU can respond to throttle inputs that quickly, i'd assume if you swapped in a lightweight flywheel and lightweight underdrive pulley, the system would not overrev the engine. It will back off once the target RPM is reached.

PS. I'm not an expert.