Re: How do you get the best acceleration from a gravity-powered car?

You can look at your system of pulleys as a system that transforms
gravitational potential energy into kinetic energy. In this view it is
clear that the final VELOCITY depends only on the efficiency of the
energy transformation. This efficiency does not depend directly on
what axle you choose to drive. It depends mainly on how much friction
is in your system. And this will increase with the number of
pulleys.

However, if you are interested in ACCELERATION then the answer is that
you can make it as big as you want (neglecting friction) by
choosing properly the system of pulleys (especially by choosing the
radius of each pulley). But you cannot make it at the same time as big
as you want AND for as long as you want it. So the final velocity will
be a constant.

These are only some thoughts to help you understand the system by
looking at it from another (?) perspective. If you have other
specific questions on this subject email me: radugrigore@ieee.org