Enter the bore diameter, stroke length, and number of cylinders into the calculator to determine the engine displacement.
Bore X Stroke Formula
The following formula is used to calculate the engine displacement using bore and stroke measurements.
ED = (π/4) * D^2 * S * N / 1000
Variables:
- ED is the engine displacement (cc)
- D is the bore diameter (mm)
- S is the stroke length (mm)
- N is the number of cylinders
To calculate the engine displacement, first square the bore diameter. Then multiply this result by the stroke length. Multiply this result by the number of cylinders. Finally, multiply by π/4 to get total swept volume in mm³, then divide by 1000 to convert to cubic centimeters (cc), since 1 cc = 1000 mm³.
What is a Bore X Stroke?
Bore X Stroke refers to the diameter of the cylinder in an engine (bore) and the distance the piston travels within the cylinder (stroke). These two measurements determine the engine’s total displacement, or the total swept volume of the cylinders (and thus the theoretical maximum air/fuel charge volume) during one complete engine cycle. In general, a larger bore and stroke equates to a larger displacement, which can produce more power. However, the ratio between the bore and stroke also affects the engine’s efficiency and power characteristics.
How to Calculate Bore X Stroke?
The following steps outline how to calculate the Bore X Stroke using the given formula:
- First, determine the bore diameter (D) in millimeters (mm).
- Next, determine the stroke length (S) in millimeters (mm).
- Next, determine the number of cylinders (N).
- Next, square the bore diameter (D^2).
- Next, multiply the squared bore diameter (D^2) by the stroke length (S).
- Finally, multiply by the number of cylinders (N) and by π/4, then divide by 1000 to convert from mm³ to cubic centimeters (cc) and get the engine displacement (ED).
Example Problem:
Use the following variables as an example problem to test your knowledge:
bore diameter (D) = 80 mm
stroke length (S) = 75 mm
number of cylinders (N) = 4
