1. What is Engine CFM?

CFM (Cubic Feet per Minute) is a measurement of airflow that indicates how much air flows through an engine at a given RPM. It's an important factor in engine performance and efficiency.

2. How Does the Calculator Work?

The calculator uses the CFM formula:

Where:

• \( RPM \) — Engine revolutions per minute
• \( Displacement \) — Engine displacement in cubic inches (ci)
• \( 3456 \) — Conversion factor to get CFM

Explanation: The formula calculates the theoretical airflow through an engine based on its displacement and RPM.

3. Importance of CFM Calculation

Details: Knowing your engine's CFM requirements helps in selecting the right carburetor or fuel injection system, and optimizing engine performance.

4. Using the Calculator

Tips: Enter engine RPM and displacement in cubic inches. Both values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What is the 3456 constant in the formula?
A: It's a conversion factor that accounts for the number of cubic inches in a cubic foot (1728) and the fact that a four-stroke engine only takes in air every other revolution (×2).

Q2: Is this the actual CFM my engine needs?
A: This is theoretical CFM. Actual requirements may vary based on volumetric efficiency and other factors.

Q3: How does CFM relate to horsepower?
A: Generally, more CFM means more potential horsepower, but the relationship depends on engine efficiency and other factors.

Q4: What's a typical CFM range for engines?
A: Small engines might need 150-350 CFM, while high-performance engines can require 600-1000+ CFM.

Q5: Does this apply to both carbureted and fuel injected engines?
A: Yes, the basic airflow calculation applies to both, though fuel delivery systems differ.