I'll just start by saying electric motors are not generic things.
For example, the 9" ADC motors used in the White Zombie are rated at 28hp each. That's roughly HALF of the power in the MGR. Siamezed, they will put out 56 hp.
If you look at the data from an ADC motor, you'll see two important things:
1) The whole power chart runs between 2500 rpm and 6500 rpm.
2) The torque speed chart totally disagrees with the specs, which claim stall torque numbers of 1000ft-lb using 144V. I'm going to assume below 2500 RPM is the "constant torque" region of performance, and this motor therefore puts out about 100ft-lb of torque from 0 rpm to 2500 rpm.
How does this compare to the MGR?
a) The MGR is rated to 10,500 rpm, and can probably run to 13,000 rpm - twice that of the ADC 9" motor.
b) The MGR's motor puts out a similar amount torque: 96 ft-lbs to 610 rpm and about 80 ft-lbs to 4500 rpm.
If you had a gearbox like the MGR ( 6.86:1 gear ratio ) and used the ADC 9" motor, the constant torque range would end at 30mph and the motor's max speed would limit the car to about 70mph.
This doesn't sound too bad until you look at the power curve, which indicates it will only be putting out 10 ft-lbs of torque at 6000 rpm. That's only 12hp. Siamezing the motors will only double your power - you still need a transmission to use the motor's capability. The reason the White Zombie performs so well is the motors are pushed WAY beyond their specs - and are only expected to do this for 10 to 15 seconds. He's pushing something like 355 volts, where all numbers for ADC 9" motors end at 144V. He's also pushing something like 2000A, while the ADC chart ends at 450A, but also shows a stall torque of 1000 ft-lbs using 3000A. None of this agrees with itself.
However, pushing something like 10X the rated current through a motor might be just fine if drag racing is your thing. In this case, 2000A * 355V = 710kW
- That's 952 HP!!
No wonder he's so fast.
Compare that to the MGR, which puts out full torque until about 5000 rpm and a top speed of 13000 rpm. This means that through the normal driving speed range (up to about 60mph) you've got full torque. The full capability of the motor is available. If you really want a speeding ticket, you can push the motor to it's rpm limit at 140mph.
So, you're right - if you assume all electric motors perform like a big DC motor. But, they don't - that's why I'm using the MGR.
Regarding the ORNL "continuous" test - 50kW is near full power for that motor. How long could you keep the pedal mashed to the floor with an IC engine? Not very long, in my experience. You'd slow down to save your equipment. The same test performed by ORNL using 25kW and 25C coolent showed much longer run time - something like 35 minutes.
-e*clipse