More compression = more bang = more power.
With more compression you will have to run a higher octane fuel. The more compression the greater chance of pre detonation or knocking. Detroit Diesel engines fire because of compression. No intake valves, no spark plugs Air is forced into the cylinder from the blower through the intake ports. As the piston compresses the air the fuel injector atomizes the fuel right before Top Dead Center. The high compression creates heat. Combined with the atomized fuel, it fires. Most diesels have very big starters and big batteries to combat the high compression. To shut them down you cut the fuel supply. Most of the giant motors we had on the drilling rigs I worked on had air starters. With an air starter you can crank and crank and not worry about running the battery down or burning up the wiring.
