Movement speed formula help

[CharmingClyde]

I'm working on a formula to calculate 1/4 mile times in my racing game that uses attack (atk) and defense (def) to simulate power-to-weight ratio.

The goal is to create noticeable speed differences between light/heavy and low/high power cars.

 

Currently, my formula is:

 

Milliseconds per tile = 1000 / (140 * int(atk) / int(def))

 

This roughly matches real 1/4 mile times without requiring huge speed stats. However, the speed difference between, say, 182 atk and 1000 atk cars isn’t as distinct as it should be.Before, I used:

 

Milliseconds per tile = 1000 / (1 + ln(speed))

 

with speed representing horsepower, but this required extremely high speed values to get realistic times.

I’m not confident with the math here—any advice on a better formula to scale power-to-weight properly? Also, is there a way to avoid using int() in the source code calculations?