In article -
maine.net, says...


Assume you release equal masses of air, the pistons have
the same area, and the cylinders are long enough to fully
expand the air. The 100 psi (assume absolute pressure)
piston will exert twice the initial force and will also
have travelled over twice as far when the air is fully
expanded. The force/displacement curve is not linear (Don
already caught me on that), but it should be obvious that
the total work available from the piston is considerably
greater in the unregulated case.

Sorry, wasn't thinking straight here. We're talking equal
masses, not equal volumes, so the displacements will be the
same, but the initial force will be twice for the
unregulated case.

Ned Simmons