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Bore/Stroke Ratio Formula:
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The bore/stroke ratio is a fundamental parameter in engine design that compares the cylinder bore diameter to the piston stroke length. It helps determine engine characteristics and performance capabilities.
The calculator uses the bore/stroke ratio formula:
Where:
Explanation: The ratio is calculated by simply dividing the bore measurement by the stroke measurement, resulting in a unitless value.
Details: The bore/stroke ratio significantly influences engine characteristics. A ratio greater than 1 indicates an oversquare engine (better for high RPM), a ratio less than 1 indicates an undersquare engine (better torque at low RPM), and a ratio equal to 1 indicates a square engine.
Tips: Enter bore and stroke measurements in inches. Both values must be positive numbers greater than zero for accurate calculation.
Q1: What is considered a good bore/stroke ratio?
A: There's no single "good" ratio - it depends on the engine's intended purpose. High-performance engines often have ratios >1, while torque-focused engines may have ratios <1.
Q2: How does bore/stroke ratio affect engine performance?
A: Higher ratios generally allow for higher RPM operation and better breathing, while lower ratios typically provide better low-end torque and mechanical efficiency.
Q3: Can I use metric measurements?
A: Yes, as long as both measurements use the same units (mm, cm, etc.), the ratio will be the same. The calculator currently accepts inches but the ratio is unitless.
Q4: What's the typical range for bore/stroke ratios?
A: Most production engines have ratios between 0.8 and 1.2, though racing engines can exceed these limits.
Q5: Does bore/stroke ratio affect fuel efficiency?
A: Yes, the ratio influences combustion efficiency, friction losses, and thermal efficiency, all of which impact fuel economy.