Quote:
Originally Posted by Vman455
Has anyone proven empirically that in the case of two cars, with identical Cd and frontal area but different masses, the heavier car will roll faster downhill? Does the increased momentum of a heavy car outweigh (ha!) the increased rolling resistance at some point, and where is that point?
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I have a couple empirical observations: When I have two passengers and two dogs in the Geo, I can scrub 5mph or 300 yds off my EOC starting point vs. just me in the car. The car just rolls and rolls. 300# pounds of extra inertia in the Geo is equivalent to about 40 degrees ambient temperature difference when it comes to EOC roll out. That said, overall mpg is always best when it's just me in the car. Energy wasted accelerating the extra weight is not completely made up for by the longer rolling distance.
Second, my 7L 400hp 7000# 15 passenger van rolls forever. It gets 20mpg vs my Metro's 65mpg which only rolls about half as far on a glide.