1. What is the Fuel Injector Flow Rate Equation?

The Fuel Injector Flow Rate equation calculates the required fuel flow rate for each injector based on engine horsepower, fuel consumption, number of injectors, and duty cycle. It helps ensure proper fuel delivery for optimal engine performance.

2. How Does the Calculator Work?

The calculator uses the following equation:

Where:

• \( HP \) — Engine horsepower
• \( BSFC \) — Brake specific fuel consumption (lb/hp h)
• \( Number\ of\ Injectors \) — Total injectors in the system
• \( Duty\ Cycle \) — Injector duty cycle (decimal 0-1)

Explanation: The equation calculates the required fuel flow per injector by dividing the total fuel requirement (HP × BSFC) by the number of injectors and their duty cycle.

3. Importance of Proper Injector Sizing

Details: Properly sized fuel injectors are crucial for engine performance. Undersized injectors can cause lean conditions and engine damage, while oversized injectors can cause poor idle quality and fuel economy.

4. Using the Calculator

Tips: Enter engine horsepower, typical BSFC (0.45-0.60 for NA engines, 0.60-0.80 for forced induction), number of injectors, and desired duty cycle (typically 0.8 for street applications).

5. Frequently Asked Questions (FAQ)

Q1: What is a typical BSFC value?
A: Naturally aspirated engines: 0.45-0.50, Turbocharged engines: 0.60-0.70, Supercharged engines: 0.55-0.65.

Q2: What's a safe duty cycle for street applications?
A: 80% (0.8) is commonly recommended for street applications, allowing headroom for variations.

Q3: Should I use all injectors in the calculation?
A: Yes, unless you're running staged injection where secondary injectors only activate at higher RPM.

Q4: How do I convert lb/h to cc/min?
A: Multiply lb/h by 10.5 to get cc/min (for gasoline with SG ~0.72-0.74).

Q5: What about fuel pressure changes?
A: Flow rate changes with the square root of pressure ratio. This calculator assumes rated flow at specified pressure.