1. What is an Injector to HP Calculator?

Definition: This calculator estimates the maximum horsepower supported by fuel injectors based on their flow rate, quantity, duty cycle, and brake specific fuel consumption.

Purpose: It helps automotive enthusiasts and mechanics determine if their fuel injectors can support their engine's power requirements.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( HP \) — Supported horsepower
• \( Flow \) — Injector flow rate (lb/hr)
• \( N \) — Number of injectors
• \( DC \) — Duty cycle (0-1, typically 0.8-0.9 for performance)
• \( BSFC \) — Brake specific fuel consumption (lb/HP·hr)

Explanation: The total fuel flow capacity is divided by the engine's specific fuel consumption to determine maximum supported power.

3. Importance of Injector Sizing

Details: Proper injector sizing ensures adequate fuel delivery for engine performance while preventing lean conditions that can damage engines.

4. Using the Calculator

Tips: Enter injector flow rate (lb/hr), number of injectors, duty cycle (0.8 recommended), and BSFC (0.5 for NA, 0.6-0.7 for forced induction). All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: What is BSFC?
A: Brake Specific Fuel Consumption measures how efficiently an engine uses fuel. Lower values mean more efficiency (NA engines ~0.45-0.5, forced induction ~0.55-0.65).

Q2: What's a safe duty cycle?
A: 80% (0.8) is common for performance, 90% (0.9) maximum for short durations. Higher values risk injector failure.

Q3: How do I find my injector flow rate?
A: Check manufacturer specs or divide rated cc/min by 10.5 to get lb/hr (approximately).

Q4: Should I include a safety margin?
A: Yes, it's recommended to have 10-20% more injector capacity than your target horsepower.

Q5: What if I have different size injectors?
A: Use the smallest injector's flow rate for conservative estimates, or calculate each bank separately.