Supercharger RPM Calculator

Crank Pulley Diameter (in):

Supercharger Pulley Diameter (in):

Engine RPM:

Calculate

 

 

About Supercharger RPM Calculator (Formula)

A supercharger is a device that forces additional air into an internal combustion engine’s intake manifold, allowing the engine to burn more fuel and produce more power. To design and optimize a supercharger system, engineers often use an RPM (Revolutions Per Minute) calculator to determine the supercharger’s ideal speed for a given engine and desired performance characteristics.

The formula for calculating the supercharger’s required RPM is based on the engine’s volumetric efficiency, desired boost pressure, and other factors. Here’s a simplified version of the formula:

Supercharger RPM=Engine RPM×Volumetric EfficiencySupercharger Compression Ratio Supercharger RPM=Supercharger Compression RatioEngine RPM×Volumetric Efficiency​

Where:

• Supercharger RPM: The revolutions per minute of the supercharger.
• Engine RPM: The revolutions per minute of the internal combustion engine.
• Volumetric Efficiency: This represents the engine’s ability to draw in air and fuel. It is usually expressed as a decimal (e.g., 0.85 for 85% volumetric efficiency).
• Supercharger Compression Ratio: This is the ratio of the pressure at the supercharger’s outlet to the pressure at its inlet. It quantifies the amount of boost or pressurization provided by the supercharger.

Here’s how the formula works:

1. You start with the engine’s RPM, which is determined by the engine’s design and operating conditions.
2. You multiply the engine’s RPM by the volumetric efficiency, which represents the percentage of air the engine can draw in compared to its total capacity when operating at its best.
3. Finally, you divide the result by the supercharger’s compression ratio. The compression ratio defines how much the supercharger is pressurizing the air before it enters the engine’s intake manifold.

By using this formula, you can calculate the required supercharger RPM to achieve a specific level of boost pressure and volumetric efficiency. This information is essential for selecting the right supercharger size and design to match the engine’s needs and performance goals.

It’s important to note that real-world supercharger systems can be more complex, and various factors like temperature, humidity, and engine modifications can influence the actual supercharger speed and performance. Therefore, this simplified formula serves as a starting point for initial estimations, and more detailed engineering analysis may be required for precise supercharger system design.