Injector Size Calculator
Unit Converter ▲
Unit Converter ▼
From:  To: 
Find More Calculator☟
The Injector Size Calculator helps you determine the appropriate fuel injector size for your engine, based on horsepower, the number of cylinders, BSFC (Brake Specific Fuel Consumption), and the desired injector duty cycle. Proper injector sizing is crucial to ensure optimal engine performance and efficiency.
Historical Background
Fuel injectors have been a key component of internal combustion engines since their introduction in the mid20th century. Properly sizing injectors is critical for delivering the correct amount of fuel to the engine, which impacts both power output and fuel efficiency. Oversized or undersized injectors can lead to poor performance, excessive emissions, or engine damage.
Calculation Formula
The formula to calculate the required injector size is:
\[ \text{Injector Size (cc/min)} = \frac{\text{Horsepower} \times \text{BSFC}}{\text{Number of Cylinders} \times \left(\frac{\text{Duty Cycle}}{100}\right)} \times 10.5 \]
Example Calculation
If your engine has 300 HP, 8 cylinders, a BSFC of 0.5, and you want an 80% duty cycle:
\[ \text{Injector Size} = \frac{300 \times 0.5}{8 \times 0.8} \times 10.5 = 246.09 \text{ cc/min} \]
Importance and Usage Scenarios
Correctly sizing injectors ensures your engine operates efficiently and safely. This is particularly important for highperformance engines where precise fuel delivery is crucial for achieving desired power levels without causing engine damage.
Common FAQs

What is BSFC?
 BSFC stands for Brake Specific Fuel Consumption, a measure of the fuel efficiency of an engine at producing power.

Why is injector duty cycle important?
 The duty cycle represents the percentage of time the injector is open. Keeping this within optimal ranges prevents injector overloading and ensures reliable performance.

How can I optimize my fuel injector size?
 Consider your engine's specific power output, the number of cylinders, and the desired duty cycle to select injectors that balance performance and efficiency.