Penske Racing Shocks 7300 Series - Manual (Page 22)

Dyno Graph Overview
An easy way to help picture what is going on here is to relate the graph’s shape to what the dyno is doing to the shock. The
dyno uses a scotch yoke system (shown above), where the motor turns a crank and the sliding yoke allows the main dyno
shaft to make the up and down movement at the preset stroke. The dyno software takes thousands of measurements
throughout a single revolution of the crank. The sampled points are connected to form the graph. By relating the crank’s
position to the corresponding graph quadrant and the circular crank movement may help in reading the graphs.
QUADRANT #4
This quadrant begins with the
rebound valve stack open. Where
the graph crosses the zero line
(inches) in quadrant #4 is the
maximum force produced by the
rebound valving. As the shock
approaches the full extension point,
the rebound valve stack begins to
close as it approaches the
compression movement. At this
point the cycle starts over again in
quadrant #1.
QUADRANT #1
This is the beginning of the
compression stroke. Where the
graph crosses the zero line
(pounds) in quadrant #1 begins the
compression stroke. Approximately
the first 1/2" of displacement is
formed with relation to the low
speed bleed bypass. When the
shaft reaches a certain velocity, the
low speed bleed bypass shuts off
and the compression valve stack
begins to react.
QUADRANT #2
This quadrant begins with the
compression valve stack open.
Where the graph crosses the zero
line (inches) in quadrant #2 is the
maximum force produced by the
compression valving. As the shock
approaches the full compression
point, the compression valve stack
begins to close as it approaches
the rebound movement.
QUADRANT #3
This quadrant begins with the
shock at full compression and the
compression valve stack closed.
Where the graph crosses the zero
line (pounds) in quadrant #3 begins
the rebound stroke. Approximately
the first 1/2" of displacement is
formed with relation to the rebound
bleed through the shaft and jet.
When the shaft reaches a certain
velocity, the bleed shuts off and the
rebound valve stack begins to
react.