Number of Cylinders


ci = (number of cylinders)(3.14)(stroke)(bore / 2)2

maximum rpm due to mass = 0.0056 x ci2 - 8.89 x ci + 11527


Bore_istock

What you do:

Choose the number of cylinders that gives you the desired cubic inches of displacement.


Factors to consider:

1. The more cylinders you have the higher the ci (cubic inches or in3) displacement you have, the higher the torque your engine will produce. Bigger engines have more torque because they produce the power faster. They produce power faster because more air can be drawn or pushed in to an engine with many cylinders every revolution of the crank. Large ci engines produce power at a higher rate per rpm (revolutions per minute) than smaller engines.

2. The higher the ci displaced, the lower the maximum rpm. Engines with more cylinders, longer strokes and larger pistons have more mass rotating, so there is more stress on the crank. The crank can only handle so much stress, so rpm is limited.

The HiPerMath equations are:

ci = (number of cylinders)(3.14)(stroke)(bore / 2)2

maximum rpm due to mass = 0.0056 x ci2 - 8.89 x ci + 11527

3. The number of cylinders ranges from 6 - 8. This is because in the real world, the parts for engines with more than 8 cylinders are very expensive. Very few drag racers use engines with more than 8 cylinders.


Definitions:

ci = cubic inches or in3
stroke = the distance the piston travels in the cylinder.
bore = the diameter of the cylinder.
rpm = revolutions per minute