How many cc is 20 horsepower?

The relationship between horsepower (hp) and cubic centimeters (cc) depends on the engine's efficiency and design. Generally, a rough estimate is that 1 horsepower is produced by about 15 to 17 cc in a gasoline engine. Therefore, 20 horsepower would roughly correspond to an engine size of around 300 to 340 cc. However, this can vary widely based on the specific engine characteristics and type.