Battery capacity does matter, a bit indirectly; you're limited in how much current the pack can supply or recharge with. All batteries have recommended charge/d

Battery capacity does matter, a bit indirectly; you're limited in how much current the pack can supply or recharge with. All batteries have recommended charge/discharge rates based on C, the capacity in Amp-hours. A lot of NiMH batteries are around C/3 or C/4, for example. Much progress has been made in raising Li-Ion "C" rates, which is why we now have cell phones that can charge at 20W or more. Graphene batteries are starting to get common in RC battery packs and appear to be the next significant jump. TLDR: no you can't just put a really small pack in big enough to do one run, unless it's a specially designed pack with a very high discharge rate...in which case it might have worse energy density, and you might be back where you started (but with less total energy storage.) Also, minor point of order: dragsters don't use gasoline, they use nitromethane. And the limitations are material science; you need an engine with internals, and a frame, and wheels, and tires, that can all withstand enough force without being destroyed...in a sport where every bit of weight slows you down.