1. What is Supercharger Pulley Ratio?

The supercharger pulley ratio determines how many times the supercharger rotates relative to the engine's crankshaft. A higher ratio means the supercharger spins faster, creating more boost but also increasing stress on the system.

2. How Does the Calculator Work?

The calculator uses the pulley ratio formula:

Where:

• Crank Pulley Diameter — Diameter of the crankshaft pulley (inches)
• Supercharger Pulley Diameter — Diameter of the supercharger pulley (inches)

Explanation: The ratio represents how many times the supercharger rotates for each rotation of the crankshaft.

3. Importance of Pulley Ratio

Details: Proper pulley ratio is crucial for optimizing supercharger performance. Higher ratios increase boost but may require supporting modifications to the fuel system and engine management.

4. Using the Calculator

Tips: Measure both pulley diameters accurately in inches. Enter the values and the calculator will determine the ratio. Both values must be greater than zero.

5. Frequently Asked Questions (FAQ)

Q1: What is a typical supercharger pulley ratio?
A: Most factory supercharger systems have ratios between 2.0:1 and 3.5:1, but this varies by application.

Q2: How does pulley ratio affect boost pressure?
A: Higher ratios spin the supercharger faster, creating more boost. Generally, a 10% increase in ratio yields approximately 15-20% more boost.

Q3: Can I change my pulley ratio safely?
A: Small increases are usually safe, but significant changes may require upgraded fuel system, intercooling, and engine tuning to prevent damage.

Q4: How do I measure pulley diameter accurately?
A: Measure the outer diameter where the belt rides. For best accuracy, use calipers and measure across the center of the pulley.

Q5: What's the difference between pulley ratio and boost pressure?
A: Pulley ratio determines supercharger speed, while actual boost pressure depends on many factors including engine displacement, volumetric efficiency, and supercharger efficiency.