Witch Hunter Fuel Injection Calculator

Witch Hunter Sizing:

\[ Size = \frac{HP \times BSFC}{Injectors \times Duty\ Cycle} \]

HP (hp):

BSFC (lb/hp hr):

lb/hp hr

Injectors (number):

number

Duty Cycle (decimal):

decimal

Size (cc/min):

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1. What is the Witch Hunter Fuel Injection Calculator?

The Witch Hunter Fuel Injection Calculator helps determine the proper fuel injector size needed for an engine based on horsepower, brake specific fuel consumption (BSFC), number of injectors, and desired duty cycle.

2. How Does the Calculator Work?

The calculator uses the following equation:

\[ Size = \frac{HP \times BSFC}{Injectors \times Duty\ Cycle} \]

Where:

\( Size \) — Required injector size in cc/min
\( HP \) — Engine horsepower
\( BSFC \) — Brake specific fuel consumption (lb/hp hr)
\( Injectors \) — Number of fuel injectors
\( Duty\ Cycle \) — Maximum injector duty cycle (decimal)

Explanation: The equation calculates the minimum injector size needed to support the engine's fuel requirements at maximum power while maintaining a safe duty cycle.

3. Importance of Proper Fuel Injector Sizing

Details: Correct injector sizing is crucial for engine performance and reliability. Undersized injectors can lead to lean conditions and engine damage, while oversized injectors can cause poor idle quality and drivability issues.

4. Using the Calculator

Tips: Enter realistic values for your engine setup. Typical BSFC values range from 0.45-0.55 for naturally aspirated engines and 0.55-0.65 for forced induction. A safe maximum duty cycle is typically 80%.

5. Frequently Asked Questions (FAQ)

Q1: What is BSFC and how do I determine it?
A: BSFC (Brake Specific Fuel Consumption) measures how efficiently an engine uses fuel. It varies by engine type and can be estimated based on similar engines or measured with proper equipment.

Q2: Why is duty cycle important?
A: Duty cycle represents the percentage of time the injector is open. Running injectors at 100% duty cycle can cause overheating and inconsistent fuel delivery.

Q3: How do I convert lb/hr to cc/min?
A: The calculator provides results in cc/min. To convert lb/hr to cc/min, multiply by 10.5 (for gasoline).

Q4: Should I account for future power upgrades?
A: Yes, it's recommended to size injectors for your target power level rather than current power if you plan upgrades.

Q5: What about different fuel types?
A: This calculator is for gasoline. For E85 or other fuels, you'll need to account for their different stoichiometric ratios.