Engine Intake Diameter Calculator

Calculate the optimal intake diameter for your engine based on displacement, RPM, and airflow requirements.

Input Parameters

Calculation Results

Calculated Intake Diameter

0.00 inches

Based on the input parameters and assuming ideal conditions.

Calculation Formula

Diameter (in) = √[(4 × Airflow (cfm) / (π × RPM × N × CFM_factor))²]

Where:
π = Pi (approximately 3.14159)
N = Number of Cylinders
CFM_factor = 2 (for efficient flow)
RPM = Maximum RPM

Engine Intake Diameter Calculator Usage Guide

Learn how to use the Engine Intake Diameter Calculator and its working principles

How to Use This Calculator

  1. Enter the Cylinder Displacement in cubic centimeters (cc).
  2. Specify the Number of Cylinders in your engine (e.g., 4, 6, 8).
  3. Input the Maximum RPM your engine reaches.
  4. Provide the Airflow Requirement in cubic feet per minute (cfm) - this can be estimated based on desired horsepower.
  5. Click the Calculate button to determine the recommended intake diameter.

Understanding the Formula

The calculator uses the following formula to determine the optimal intake diameter:

Diameter (in) = √[(4 × Airflow (cfm) / (π × RPM × N × CFM_factor))²]

This formula ensures that the intake diameter is sufficient to handle the required airflow at the engine's maximum RPM while maintaining efficiency.

Example Scenario

For a 350cc displacement 4-cylinder engine with a maximum RPM of 8000 and an airflow requirement of 200 cfm, the calculator would recommend an intake diameter of approximately 1.41 inches.