What exactly determines Engine Size?

LBZ · Post by **LBZ** » Wed Nov 12, 2003 9:35 am

1600cc, 1641cc, 1700cc, Etc??? What is the calculation used to indicate this?

Superdrag · Post by **Superdrag** » Wed Nov 12, 2003 9:42 am

Bore times bore times stroke times 3.14. For example: 69 stroke and 94 bore equals 1914. (69 * 94 * 94 * 3.14 = 1914)

Post by **Marc** » Wed Nov 12, 2003 9:49 am

It's the total "swept" volume of all of the cylinders, determined by the bore and stroke. Nothing else has any effect on displacement.
The formula for the volume of a cylinder is π(r²)h
....pi times the square of the radius, times the height - so for a stock "1600" you'd square half of the 85.5mm bore and multiply that by pi (~3.14159) and then by the 69mm stroke, for a result of 396.16cc per cylinder.
Total displacement is 396.16 x 4 = ~1585cc

For a 4-cylinder engine you can use the shortcut method that Superdrag showed and get the same answer....well, depending upon what you use for the value of pi, anyway. Actually a 94x69 engine is over 1915cc.