Cubic Inch Displacement (CID) Formula

  • Item #: Cubic Inch Displacement
  • Manufacturer: Star
  • Condition: New
  • Engine Cubic Inch Displacement (CID) or (CI):
  • This is handy when determining what your final CID will be by using different combinations of crank stroke and overall bore diameter. We used a typical 350 Chevy small block in this example.
  • Cylinder Volume: The cylinder volume is the actual volume of just one cylinder with the piston at BDC which is calculated by the bore and the stroke times 0.7853982 (the number to calculate the area of a circle).
  • Cylinder Volume = 0.7853982 X Bore X Bore X Stroke
  • Cylinder Volume = 0.7853982 X 4.0" X 4.0" X 3.48"
  • Cylinder Volume = 43.73 CI Per Cylinder
  • Total CID = 43.73 X 8 (if you have an eight cylinder engine) = 349.84 CID, rounded off to 350 CID
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