conversion, a simple mixing chamber should normally suffice for continuous operation at a
steady speed. In addition, however, the mixing chamber should be equipped with a hand-
operated air-side control valve for use in adjusting the air/fuel ratio (optimal "actual air
volume/stoichiometric air volume" = 1.1).
Converting a spark-ignition engine results in a loss of performance amounting to as much as
30%. While partial compensation can be achieved by raising the compression ratio to E=11-
12, such a measure also increases the mechanical and thermal load on the engine. Spark-
ignition engines that are not explicitly marketed as suitable for running on gas or unleaded
gasoline may suffer added wear & tear due to the absence of lead lubrication.
The speed control of converted spark-ignition engines is effected by way of a hand-operated
throttle. Automatic speed control for different load conditions requires the addition of an
electronic control device for the throttle.
The conversion of spark-ignition engines is evaluated as follows:
• Gasoline engines are readily available in the form of vehicle motors, but their useful
life amounts to a mere 3000-4000 operating hours.
• The conversion effort essentially consists of adding a (well-turned) gas mixer.