How much more power would i need?

[Zenmervolt]

Thats not really possible to tell you with what you gave. Have to factor in wind resistance of the vehicle and gearing of the transmission, and a few other things as well.

It's quite possible assuming that he knows how much power is required to go 200 kph and he's working within a simplified system.

Total drag increases with the square of speed and power requirements increase with the cube of speed. To go twice as fast requires 8 times the power (2^3).

To go 1.2X as fast (250/200) will require twice the power (1.2^3).

ZV

 

[punjabiplaya]

'tis what that equation uses