Not all engines are created equal. In addition to generating vastly different amounts of power, engineers have a wide array of choices to match a vehicle's intended use, like a little parallel twin for a city car or a highly complicated W16 for an all-out hypercar. If you ever wonder what the most powerful automobile for a given number of cylinders is, then this list provides the answer.
For the sake of fair comparisons, we don't include hybrids on this list because their electric boost skews the results too much. For example, the Mercedes-Benz Project One's 1.6-liter V6 with four-electric motors reportedly makes 1,100 hp (820 kW), which would give it a dominating lead.
Also, these engines are in production automobiles that are currently available. In many cases, there are previously available powerplants, tuned models, or existing motorcycle mills that would win the categories.