Top Speeds in Different Gears (6MT)

Originally Posted by kannibul

Wrong. Moon has no air to resist. Dyno has no wind resistance. On the moon, the car would go as fast as it can barring friction losses with the brakes, drivetrain, front wheels, bearings, etc (provided it could breathe), and rolling losses (ie, tires). On a dyno, it'd go nearly to the theoretical limit, the difference being the same as on the moon, except without the front brakes/wheels being factors. Of course, I'm discounting gravity effect and lack of air for the moon.


So, let my try again:

You're driving along at 75MPH, 0MPH headwind. Your car is using (example) 65HP to perform this work.

You're driving along at 75MPH, 20MPH headwind. Your car is using 65+N HP now, because there is more resistance.

(You can change these numbers to driving at 75, with a 75 mph tailwind vs 75 with a 0mph wind)


Same effect applies when attempting to determine the maximum speed fo the vehicle. The faster you go, the more resistance is applied to the front of the vehicle.

As you increase speed, you increase air resistance. Lower drag coefficient means the car slips/cuts through the air more instead of creating turbulence which distorts the air, making it more resistant.

Imagine a biplane wing on a F18. It wouldn't got as fast...ever, given all things being equal.