1. What is a Compression Ratio Calculator?

Definition: This calculator determines an engine's compression ratio based on swept volume and clearance volume.

Purpose: It helps engine builders and performance enthusiasts calculate the compression ratio which affects engine power, efficiency, and fuel requirements.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( CR \) — Compression Ratio (dimensionless)
• \( V_s \) — Swept Volume (piston displacement, in³)
• \( V_c \) — Clearance Volume (combustion chamber volume, in³)

Explanation: The compression ratio is the ratio of the maximum to minimum volume in the cylinder.

3. Importance of Compression Ratio

Details: Higher compression ratios generally produce more power but may require higher octane fuel. Proper ratio calculation is crucial for engine performance and reliability.

4. Using the Calculator

Tips: Enter the swept volume (piston displacement) and clearance volume (combustion chamber volume) in cubic inches. All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: What's a typical compression ratio for street engines?
A: Most street engines range from 8:1 to 10:1, while high-performance engines may be 11:1 or higher.

Q2: How do I measure clearance volume?
A: Measure combustion chamber volume with a burette or graduated cylinder with the piston at TDC.

Q3: Does this include head gasket volume?
A: Head gasket volume should be included in your clearance volume measurement.

Q4: What's the maximum safe compression ratio for pump gas?
A: Typically 9.5:1 for 87 octane, up to 11:1 for premium 93 octane, depending on engine design.

Q5: How does compression ratio affect power?
A: Higher ratios improve thermal efficiency but may require ignition timing adjustments and higher octane fuel.