[SpEEdyBL]

Now there are two things that determine the efficiency of the motor. 1. The resistance, and 2. amount of amps the motor pulls unloaded. Ideally, a motor spinning unloaded should pull 0 amps because it is doing no work, but in reality, motors pull current unloaded because this isn't a perfect world and motors cant be made ideally. Multiply this amp value by the volts and you get the power automatically lost as heat. This is called iron loss. Then there is resistance. Energy created as heat = resistance x amps squared. To find efficiency, subtract the (resistance x amps squared) and the iron loss from amps times volts and divide that whole thing by amps times volts. So efficiency = (IE - rI^2 - I0)/(IE) where I = amps E = volts, r = resistance and I0 = iron loss. The resistance and IO for the feigao motors are given at feigao.com. But anyhow, all that really matters in terms of how powerful a motor is, is how efficient it is, because heat is the only thing that really prevents you from gearing up. I think the HV4.5 has more resistance, but much lower iron loss than the 8xl, and that is why the HV motors run cool at smaller loads and considerably warmer or hot at higher loads, while the feigao runs warm/hot at all loads, but only gradually increases in temperature has the load is added. There are some things I may need to clear up, but those will come later.