Would you go through all this trouble just to save money on gas?

With minimal alterations to the engine, Mr. Anton Peterka (from Belgrade, Serbia) made his 1985 Yugo 45 to run on wood and coal for fuel:

The process is based on incomplete combustion of wood: due to lack of air, gases are created: carbon monoxide, the main fuels, hydrogen and methane. That mixture of gases is as flammable as gasoline fumes. To get the car moving, it is necessary to "fill it up with wood". The whole mechanism is made of steel plate and it weighs 60 kg.

The highest speed that can be achieved by that type of an engine is about 85 km/h, because of the less power and the increased weight and air resistance (aerodynamics is disturbed by the external firebox). It takes about 15-20 min to start the car because the wood needs to be decomposed.

Instead of 1 litre of gasoline, 2.5 kg of wood is spent. 20 kg of wood are consumed after 100 km which means that driving "on wood" is up to 10 times cheaper than the conventional driving using gasoline. And that is not the only advantage of this kind of driving - exhaust fumes from wood have a lot less harmful components: the environment is being less polluted.

source: darkroastedblend