Originally posted by ebbfolls
Interesting concept.

What happens if the load curve is moved to the left so that it intersects both power curves before their power peaks?
Then Engine A will end up with higher top speed.

The question now would be ... "What happens to the remaining HP that both engines are capable of generating? Won't that extra HP supposed to increase the speed further?"

The answer is "No". At any speed before the top speed is reached, the difference between the load curve and an engine's power curve is the HP being used to accelerate the car. When top speed is reached, acceleration becomes zero, speed becomes constant. Beyond the top speed, the load curve becomes higher than an engine's power curve, which means that any increment in speed requires more HP than the engine could produce for the same speed increment. Hence, the extra HP from an engine cannot be used to further accelerate the car and pressing on the pedal further would only result to waste.

Moving the load curve to the left might be akin to changing the aerodynamics of the car where wind drag is increased. If we deploy a parachute on the rear of the car, its top speed would be severely limited and pushing the engine further would only waste the tires while speed remains constant.