To determine PWR, input estimated weight and horsepower for an estimated power to weight ratio.
A car with a high power to weight ratio will accelerate faster than one with a low power to weight ratio.
For example, a motorcycle is fast despite having a small engine in comparison to a truck because the power to weight ratio is greater than that of a truck.
If two vehicles had the same size engine, such as a motorcycle and car, the motorcyle is more likely to be fastest because it has less weight to move.
Power to weight ratio is single handedly one of the best predicting techniques to measure speed.