[88CRX]

How do you a coast down test to find out Aerodynamic Cd?

I'll guess the following:

1) Car in Neutral

2) Performed on a flat road, so weight will not factor in (on an incline, if you have a heavy car it will not slow down as fast as a light car). You can technically do it in an incline but the angle must be factored in.

What speed do I start and end the clock? It should be faster speed, because at low speeds, the percentage of mechanical energy loss will be a larger, because the affects of Aerodynamic Cd is less at lower speed. So I'm guessing start at 80mph down to 60mph.

Given the mass of car, speed, and time to Aerodynamic Cd, what equation do i use to convert to Cd. I'm guessing there will be a factor to compensate for Mechanical losses.