This discussion brings me back to a game available on the Playstation 2 name NHRA drag racing 2. It was a very technical accurate game, and one had total control over every aspect of an engine, e.g. bore, stroke, number of cylinders, compression ratios, what kind of valve train the engine had such as solid or roller lifters... and every one of those fields had an effect on torque, horsepower, and maximum revolutions of the engine. All of these things should be considered in Gear City. I really want to see this game end up being as technically correct as it possibly can be.
On the topic of the number of cylinders having an effect on engine performance... The number of cylinders is independent of displacement. Displacement and volumetric efficiency is what determines the fuel economy (brake specific power consumption) of an engine. For any given displacement, the number of cylinders will have an effect on rotational mass (how fast the engine will rev up and down). One huge piston at 400 cubic inches, or twelve small pistons that displace 400 cubic inches. This also has a direct effect on rpm characteristics. Think about real engines. I'm American so bear with me. Take a dodge hemi engine. A 5.7 liter eight cylinder push rod engine and two valves per cylinder. Low volumetric efficiency (Junk from the dark ages). That engine averages 16 mpg, and produces around 347 horsepower. Now take a honda civic. 1.7 liters, single overhead cam and four valves per cylinder. That engine is advertised to put out 127 horsepower, and averages about 27 mpg. Lets use horsepower per liter as our proportion. 357 horsepower divided by 5.7 liters yields 60.88 horsepower per liter. The civic: 127 horsepower divided by 1.7 liters yields 74.7 horsepower per liter. The honda engine makes more horsepower with what it has to work with in displacement compared to the hemi engine, and on top of that, the honda provides around 30 percent better fuel economy under normal driving than the chrysler hemi motor. Based off that information, things like how many valves per cylinder and displacement are what determine fuel economy and power.
On the topic of the number of cylinders having an effect on engine performance... The number of cylinders is independent of displacement. Displacement and volumetric efficiency is what determines the fuel economy (brake specific power consumption) of an engine. For any given displacement, the number of cylinders will have an effect on rotational mass (how fast the engine will rev up and down). One huge piston at 400 cubic inches, or twelve small pistons that displace 400 cubic inches. This also has a direct effect on rpm characteristics. Think about real engines. I'm American so bear with me. Take a dodge hemi engine. A 5.7 liter eight cylinder push rod engine and two valves per cylinder. Low volumetric efficiency (Junk from the dark ages). That engine averages 16 mpg, and produces around 347 horsepower. Now take a honda civic. 1.7 liters, single overhead cam and four valves per cylinder. That engine is advertised to put out 127 horsepower, and averages about 27 mpg. Lets use horsepower per liter as our proportion. 357 horsepower divided by 5.7 liters yields 60.88 horsepower per liter. The civic: 127 horsepower divided by 1.7 liters yields 74.7 horsepower per liter. The honda engine makes more horsepower with what it has to work with in displacement compared to the hemi engine, and on top of that, the honda provides around 30 percent better fuel economy under normal driving than the chrysler hemi motor. Based off that information, things like how many valves per cylinder and displacement are what determine fuel economy and power.