I can't help it. I had to register to reply.

Assuming that rolling resistance and drivetrain losses do not change with speed, the only thing left is aerodynamic drag. As I figure it the power required to go a given speed is proportional to the cube of velocity(v) rather than the square. In other words:

P=1/2*C*r*A*v^3 where:

C is the coefficient of drag, assumed to be constant

r is the density of air, assumed to be constant under about Mach .5

A is the frontal area of the car

v is the velocity (speed)

I may or may not be able to figure out how to post the derivation of this. Nevertheless, after making some initial estimations of the constants, it predicts that you would need, in flywheel horsepower,

140mph requires 217hp

150mph requires 265hp

160mph requires 319hp

170mph requires 381hp

180mph requires 451hp

190mph requires 529hp

200mph requires 616hp

For any of you who know your flywheel hp and top speed, how close is this prediction?

Tim