Robert,

There are two types of HP to deal with in EV's, there is the electrical HP I call HPe and the mechanical HP I refer to as HPm: The formulas are:

(ft. lbs. of torque * RPMs)

HPm= -------------------------

5252

(Volts * Amps)

HPe=---------------

746

(BTW: due to losses, etc. you can actually end up with a more accurate/quick idea of HP comparisons by simply using 1000 rather than 746....)

Small, high RPM motors can produce almost equivalent HPm to an 11" motor, however the larger motor will likely sustain the HP longer.

If you compare an ImPulse 9 motor to a WarP 11 they look like this at 72 volts:

ImPulse 9 WarP 11

25 50 ft lbs

233.8 235.5 amps

4013 2094 RPMs

22.6 22.7 HPe

19.1 19.9 HPm

Basically, the ImPulse 9 produce 1/2 the torque of the WarP 11, but at almost twice the RPMs - thus the HP's are almost equivalent! This is why many racers are seeing the benefits of two smaller motors! Two ImPulse 9's can produce the same torque as an 11, but at twice the RPM's! (and while consuming twice the power. This is okay for racing, but maybe not ideal on the street....

Without getting into a very LONG discussion of motor HP ratings versus ICE HP ratings I will give you a few general purpose thoughts: ICE HPm is rated at PEAK, whereas most electric motors are rated as continuous duty. A 250 HP ICE might only use 20 HPm to maintain 55 MPH. Compare that to an electric motor: (excluding the fact that series wound motors produce their max torque at zero RPM..) WarP 9 and 11 motors have handled 2000 Amps for 10-15 seconds at the track - this is a peak of (170v*2000A)/746 or ~455 HPe On the street, it is common for EV's to draw ~100 amps at 144 volts to maintain 55 MPH or about 19HPe. (of course wind resistance, frontal area, coefficient of drag, etc. etc. all tie into exact numbers, but they are relatively close in HP...) The BIG difference (IMHO) s when the torque is needed and when the ICE and Electric supply it! (this is partly why ICE's need transmissions!)

Sorry to ramble on.....

George