Brake Horsepower (BHP) and Horsepower (HP) both measure engine power, but BHP reflects the power after losses from the drivetrain, while HP represents the power produced at the engine itself.
Understanding Horsepower (HP)
Horsepower is a unit of measurement for power, defined as the rate at which work is done. In the context of an engine, horsepower indicates how quickly the engine can perform a certain amount of work. HP is typically measured at the engine's crankshaft, before any power is lost through components like the transmission, differential, and axles.
Understanding Brake Horsepower (BHP)
Brake Horsepower (BHP) refers to the actual power available after accounting for losses within the vehicle's drivetrain. These losses occur due to friction and other inefficiencies within the transmission, differential, axles, and other related components. BHP is often measured at the wheels using a dynamometer (dyno).
Key Differences Summarized
| Feature | Horsepower (HP) | Brake Horsepower (BHP) |
|---|---|---|
| Measurement | At the engine's crankshaft | At the wheels (after drivetrain losses) |
| Value | Higher number | Lower number |
| Represents | Raw engine power | Usable power to accelerate the vehicle |
| Drivetrain Loss | Does not account for | Accounts for |
Why BHP Matters
BHP is a more realistic indicator of a vehicle's performance because it represents the power actually delivered to the wheels, which is what ultimately propels the vehicle forward. HP is useful for understanding the engine's potential, but BHP provides a more accurate picture of real-world acceleration and performance.
Example
Imagine an engine produces 200 HP. After the power goes through the transmission, differential, and other drivetrain components, some of that power is lost due to friction and inefficiency. The power delivered to the wheels might only be 170 BHP. This difference of 30 HP represents the power lost within the drivetrain.
