One common
question is how much
power increases when
compression is
boosted. The
following graph
shows the maximum
power increase as
compression is
raised. It assumes
fuel octane
increases enough to
prevent spark knock.
The dashed line
curve shows the
point of next
compression number
up. Notice how that
curve starts curving
downward steeply but
flattens out as the
compression becomes
higher and higher.
If we look at
point A (9:1
compression) as a
starting point and
go to point B (11:1
compression) the
power increases 4%
going to 10:1 and 3%
going from 10:1 to
11:1. This is a 7%
increase total. The
formula is
