Split a database between a small car engine the ignition by sparks and small cars that use the engine, the ignition with a soft. The number of separate independent tests arranged by the type of the car:
Separate databases between small cars that use spark ignition engines with smaller cars and used with compression ignition engines. A number of independent test separately sorted by the type of the car.
Separate database between a small car with positive ignition engines, cars and small engines ignition by compression. A number of separate independent test sort by vehicle type, as follows: