Home
Back
Definition: This calculator computes the bore-to-stroke ratio (\( \text{BSR} \)) of an engine based on the cylinder bore diameter (\( B \)) and stroke length (\( S \)).
Purpose: It is used in automotive and mechanical engineering to determine the ratio between the bore and stroke of an engine, which influences engine performance, efficiency, and power characteristics.
The calculator uses the following relationship:
Where:
Explanation: Enter the bore diameter and stroke length in the chosen units, and the calculator computes the bore-to-stroke ratio. Both inputs are converted to inches for the calculation, but since the result is a ratio, the units cancel out, making the BSR unitless. The result is displayed with 5 decimal places, using scientific notation if the value exceeds 100,000 or is less than 0.0001. For default inputs (\( B = 10 \, \text{in} \), \( S = 12 \, \text{in} \)), the calculated BSR is 0.83333, matching the example in the image.
Details: The bore-to-stroke ratio is a key parameter in engine design. A higher BSR (oversquare engine) typically allows for higher RPM and better high-end power, while a lower BSR (undersquare engine) provides better low-end torque and efficiency. This calculation helps engineers optimize engine performance for specific applications.
How do I find the bore-to-stroke ratio?
Measure the cylinder bore diameter (\( B \)) and stroke length (\( S \)) in the same units (e.g., inches). Compute the bore-to-stroke ratio using the formula \( \text{BSR} = \frac{B}{S} \). The result is a unitless ratio.
What does the bore-to-stroke ratio represent?
The bore-to-stroke ratio (\( \text{BSR} \)) represents the ratio of the cylinder bore diameter to the stroke length in an engine, indicating whether the engine is oversquare (BSR > 1), square (BSR = 1), or undersquare (BSR < 1).
What is the formula for bore-to-stroke ratio?
The formula for bore-to-stroke ratio is \( \text{BSR} = \frac{B}{S} \), where \( B \) is the bore diameter, and \( S \) is the stroke length. The result is a unitless ratio.
Can I use different units for bore and stroke?
Yes, the calculator supports multiple units for bore and stroke (inches, centimeters, millimeters, meters, feet). All inputs are converted to inches for the calculation, but since BSR is a ratio, the units cancel out.
What happens if I enter zero for bore or stroke?
Entering zero for bore (\( B \)) or stroke (\( S \)) will result in the calculation not being performed, as both values must be greater than zero for a valid result.