[zeropointbug]

Finnster, are you sure you have your understanding or efficiency down?

You said: "But at 6400W @ 64V/100A, the motor could even be same or less eff and put out less heat. Thus you could run a poorer quality motor, but still have a cool system."

Heat output does not have to do with current directly, it's how much power you are putting in, how well the motor transforms that energy, and how much mechanical power is put out at the shaft. It doesn't matter if a motor has 94% eff. at 100v/5A, or 94% at 50v/10A... you will still have the same heat output for a given power input.

The correct assumption is that for a given motor, it will run more efficiently the higher the voltage. And as you up the voltage, the smart thing to do is usually run a higher turn motor (thats with same gearing). The amount of heat that is generated from current will go down proportionally as you increase voltage, and increase turns. This is NOT total heat output however, there are other losses too that contribute.

I think these larger RC cars such as truggies, we need to increase the voltage to say 36V, but that's just IMO. That would be using something like a 16-18 turn XL size motor. Or better yet a Neu, or LMT. Efficiency would go up several % points, and that makes a HUGE difference as far as heat output is concerned.

Zero