Is this a horizontal or vertical spinner? What is the diameter?

For example most heavyweight horizontal spinners are 10+ kW and vertical spinners tend to not be that heavy. You currently have a max of 4.5kW with those motors and VESC current limit on 12s.

12s * 3.7V * 50A = 2220W per motor

ERPM will have no affect on spinup time, only voltage and current.

I suggest you work out the total kinetic energy at max speed, then use that to work out how big your motors need to be to achieve the spinup time you want.

Another solution would be to use some of the VESCs that can handle higher currents being sold on here. Which will be fine for 80A. http://www.fightingrobots.co.uk/thre...perage-version