1. What is Brake Horsepower?

Brake horsepower (BHP) is the actual horsepower delivered to the pump shaft. It represents the power required to drive the pump and overcome all losses in the system.

2. How Does the Calculator Work?

The calculator uses the brake horsepower formula:

Where:

• \( Q \) — Flow rate in gallons per minute (GPM)
• \( H \) — Total head in feet (ft)
• \( SG \) — Specific gravity of the fluid (unitless)
• \( \eta \) — Pump efficiency (decimal between 0 and 1)
• 3960 — Conversion factor to get horsepower

Explanation: The equation calculates the actual power required by the pump after accounting for system losses represented by the efficiency factor.

3. Importance of BHP Calculation

Details: Accurate BHP calculation is crucial for selecting the right motor size, ensuring proper pump operation, and preventing motor overload in automotive cooling and fuel systems.

4. Using the Calculator

Tips: Enter flow rate in GPM, head in feet, specific gravity (1.0 for water), and pump efficiency (typically 0.7-0.9 for automotive pumps). All values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What's the difference between BHP and WHP?
A: Brake horsepower (BHP) is measured at the pump shaft, while wheel horsepower (WHP) is measured at the wheels after all drivetrain losses.

Q2: What's a typical efficiency for automotive pumps?
A: Most automotive pumps have efficiencies between 70-90% (0.7-0.9 in decimal form).

Q3: Why is specific gravity important?
A: It accounts for fluid density differences. Water is 1.0, gasoline is about 0.74, and coolant mixtures are typically 0.9-1.1.

Q4: How do I measure head for my car's pump?
A: Head is the pressure difference converted to feet of fluid (1 psi ≈ 2.31 ft for water).

Q5: Can this be used for electric water pumps?
A: Yes, the formula works for any centrifugal or positive displacement pump in automotive applications.