1. What is Fuel Injector Sizing?

Fuel injector sizing is crucial for engine performance. Properly sized injectors ensure the engine receives the correct amount of fuel for optimal combustion without running lean or rich.

2. How Does the Calculator Work?

The calculator uses the fuel injector sizing equation:

Where:

• \( HP \) — Engine horsepower
• \( BSFC \) — Brake specific fuel consumption (typically 0.45-0.55 for NA, 0.55-0.65 for turbo)
• \( n_{injectors} \) — Number of fuel injectors
• \( duty\_cycle \) — Maximum injector duty cycle (typically 80% or 0.8)

Explanation: The equation calculates the required fuel flow rate per injector based on engine power requirements and system configuration.

3. Importance of Proper Injector Sizing

Details: Correct injector sizing prevents engine damage from running lean, avoids poor performance from running rich, and ensures optimal fuel delivery across the RPM range.

4. Using the Calculator

Tips: For forced induction engines, use higher BSFC values. Always include a safety margin (typically 10-15%) when selecting injectors.

5. Frequently Asked Questions (FAQ)

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

Q2: What duty cycle should I use?
A: 80% (0.8) is standard for street applications. Racing may use up to 90% (0.9).

Q3: Should I use peak or average HP?
A: Use the maximum horsepower your engine produces at any RPM.

Q4: What if I have secondary injectors?
A: Calculate separately for primary and secondary injector sets.

Q5: How do I convert lb/hr to cc/min?
A: Multiply lb/hr by 10.5 to get cc/min (approximate conversion).