How Car Manufacturers Manipulate Horsepower Numbers

Car manufacturers often play games with horsepower numbers to make their vehicles appear more impressive than they really are. One common tactic is measuring horsepower at the engine’s crank (brake horsepower) rather than at the wheels, where power is actually delivered. Since drivetrain components like transmissions and differentials absorb some power, wheel horsepower is typically 10-20% lower than crank horsepower. By advertising the higher crank number, automakers inflate performance claims without technically lying. Some even optimize testing conditions—using ideal temperatures, premium fuel, or specially tuned engines—to hit peak numbers that are hard to replicate in real-world driving. Another trick involves manipulating how horsepower is measured over the engine’s RPM range. Many manufacturers highlight peak horsepower figures, even if that power is only available for a brief moment at the top of the rev range. In contrast, a car with a flatter torque curve might feel faster in everyday driving, despite having a lower peak number. Some turbocharged engines are also tuned to produce aggressive power curves that look great on paper but suffer from turbo lag or heat soak during sustained use. This means advertised horsepower may only be achievable under perfect, short-lived conditions. Finally, regulatory loopholes allow manufacturers to report inflated numbers. Different countries have varying testing standards, and some automakers exploit these differences to publish the most favorable figures. For example, a car sold in Europe might list horsepower in metric (PS), which is slightly higher than mechanical horsepower (HP), making the number appear bigger. Additionally, some companies use "factory overboost" functions—temporary power increases that last only seconds—to claim higher outputs. While these tactics aren’t outright falsehoods, they demonstrate how horsepower ratings can be misleading, leaving buyers to dig deeper for real-world performance truths.