that is what I mean... Do I absolutely need a peak 120hp motor? when 50mph = 11.7hp?
to travel at 50mph I would need a nominal 8728Watts of power to push around the vehicle...
Im sooo confused
No you don't need 120bhp.
At 50mph you would have 11.7hp in rolling resistance plus a bit in aero drag, you could say the same again, depending on how 'slippery' the car is.
You may only need a motor with 15kW nominal 1 hour rating and it will probably give you a bit more for overtaking that lorry on an up hill run for a few seconds, depending on your batteries and controller.