[GSlob]

"So how is the Zinc turned into hydrogen to be burnt in your car??? How much hydrogen to you get per pound of Zinc? What are the other byproducts?"
1. ZnO + C = CO+ Zn [at high temperature - zinc manufacture]
2. CO+ 0.5 O₂ = CO₂ + more heat [optional - disposal of CO]
3. Zn + H₂O = ZnO + H₂ [release of hydrogen from water; 32g of zinc and 9 grams of water would be needed to make 1 (one) gram of hydrogen]
Total balance:
C + H₂O = CO + H₂.

[DB]

So the car has to carry the Zinc and the water and hold the byproduct to get 1/41th its weight in hydrogen leaving the rest as dead weight. That doesn't sound very efficient.