What exactly is horsepower?

Horsepower (hp) is a unit of measurement of power (the rate at which work is done). There are many different standards and types of horsepower. The term was adopted in the late 18th century by Scottish engineer James Watt to compare the output of steam engines with the power of draft horses.

Horsepower alone is useless in a car. With thousands of horsepower but no torque a car would not even move. It is the combination of the 2 that matters. A 200hp car could be faster that a 300hp car if the 200hp one has better aerodynamics and less weight.

Generally speaking the maximum horsepower is developed at full accelerator at very near the top of the range of revs allowed - just the point that most car users never bother to use and mostly do not need to.

Maximum torque is usually developed a little further down the rev range and this is where the engine gives the best pulling ability.

Just concentrating on the power or hp tells you little about the cars capabilities as there is so much more to it than that

one horsepower is the amount of energy required for a draft horse to move 33,000 pounds a distance of one foot in one minute. Theoretically, a 300 HP car has 50% more horsepower than a 200 HP car.

Hi payback when it was actual horse power 100cc was the same as 1 horse power in engine size so a 200 horse power engine would be 20 litres which is not possible or likely. then they came up with Brake horse power which is measured using a dynometer a drum filled with water which is attached to a rolling road. this is a lot lower power in practice.