1. What is a Compression Ratio Calculator?

Definition: This calculator determines the compression ratio of an engine based on bore, stroke, and combustion chamber volume.

Purpose: It helps engine builders and automotive enthusiasts calculate the compression ratio for engine tuning and performance optimization.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( CR \) — Compression ratio (unitless)
• \( bore \) — Cylinder bore diameter (inches)
• \( stroke \) — Piston stroke length (inches)
• \( chamber \) — Combustion chamber volume (cc)

Explanation: The formula calculates the total cylinder volume (swept volume + chamber volume) divided by the chamber volume.

3. Importance of Compression Ratio

Details: Compression ratio affects engine efficiency, power output, fuel requirements, and thermal efficiency. Higher ratios typically mean more power but may require higher octane fuel.

4. Using the Calculator

Tips: Enter accurate measurements of bore diameter, stroke length, and chamber volume. 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 between 8:1 to 11:1, depending on fuel type and engine design.

Q2: How do I measure combustion chamber volume?
A: Use a burette and plexiglass plate to measure the volume of liquid needed to fill the chamber.

Q3: Does this account for piston dome/dish?
A: No, this is a basic calculator. For pistons with complex shapes, use specialized tools or include piston volume in chamber measurement.

Q4: What's the maximum safe compression ratio?
A: Depends on fuel octane, cooling system, and engine design. Consult engine specifications for your application.

Q5: Why convert inches to cc in the calculation?
A: Since chamber volume is typically measured in cc, we convert the swept volume to cc for consistent units.