# Total Displacement

on . Posted in Fluid Dynamics

Total displacement, abbreviated as DISP, is the combined volume displaced by all cylinders in an internal combustion engine.  It is typically measured in cubic inches or cubic centimeters.  To calculate the total displacement of an engine, the displacement of each cylinder is added together.  The displacement of an engine is an important factor in determining its power and torque output, as well as its fuel efficiency.  In general, larger displacement engines can produce more power and torque, but may be less fuel efficient than smaller displacement engines.

## Total Displacement formula

$$\large{ DISP = NOC \; \frac{\large{\pi}}{2} \; BORE^2 \; STROKE }$$
Symbol English Metric
$$\large{ DISP }$$ = total displacement $$\large{in}$$ $$\large{mm}$$
$$\large{ NOC }$$ = number of cylinders $$\large{dimensionless}$$
$$\large{ \pi }$$ = Pi $$\large{3.141 592 653 ...}$$
$$\large{ BORE }$$ = cylinder bore size $$\large{in}$$ $$\large{mm}$$
$$\large{ STROKE }$$ = piston stroke length $$\large{in}$$ $$\large{mm}$$ 