Damper Dyno

8/6/2019 Damper Dyno

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Unit 21 Beechlawn Ind. Complex. Greenhills Rd., Dublin 12.

Tel: (003531) 4500555 Fax: (003531) 4500585

E-Mail: [email protected]

Web Site: www.murraymotorsport.ieVAT NO: IE 6552521M

Murray Motorsport SPA Damper Dyno

For the past 20 years Murray Motorsport have specialised in sales and servicing Proflex dampers for

race, rallycross and rally cars. In recent years they have expanded the range of damper brandsavailable and now offer a range of products to cater for all levels of the market from clubman toprofessional.

Murray Motorsport has invested in a new damper dyno which now enables them offer an additionalservice the first of its kind in Ireland. Most dampers serviced will be tested afterwards and a graphwill be available for customers. Some of the basic advantages for getting your dampers tested are:

• Check they are performing correctly

• Check the position for optimum range of adjustment settings• Match the settings of each shock (equalise the left vs. right)

Sample video of the dyno in action with a Proflex damper -http://www.youtube.com/user/murrayms1?feature=mhee#p/a/u/0/cJvRtjS9a4c

How the Dyno Works:

A shock dynamometer (dyno) is a piece of equipment used to display how the damping force of a

damper changes with shaft velocity. The shock is fixed at one end, and attached to a vertical shafton its opposing end. The vertical shaft is connected to a motor in such a way that as the motorturns, the shaft displaces vertically for a set distance. A load cell at the shock’s fixed end is used tosense the amount of load on the shock and this is translated to a computer program. The motorruns through a set list of velocities, plotting how much force is being recorded at each velocity. ThisPSD Dyno can measure in various stroke lengths, speeds and the load cell can measure up to 16000

Newton’s.



Reading Dyno Results:Force vs. Velocity - Low speed shaft velocities contribute to driver feel and the car’s body movements

(sprung mass). Mid speeds shaft velocities affect the car under braking, during fast changes of direction and ride harshness. High speed shaft velocities are concerned with absorbing energy frombumps and controlling energy from the vehicle’s unsprung mass. When a shock is compressed dueto a bump, the damping force is called compression damping (or bump damping). When the shockextends due to the energy from the spring, this is called rebound damping. In this example of a

Force vs. Velocity Curve, the compression damping is displayed in the top portion of the graph and

the rebound damping in the bottom portion.

BUMP / COMPRESSION

REBOUND / EXTENSION

LOW SPEED HIGH SPEED

Force vs. Velocity Graph

Force vs. Displacement- The dyno can also be used to output a Force vs. Displacement graph.

This graph shows the force a shock generates as it travels through its motion in both thecompression damping and rebound damping phases. Force is shown on the vertical axis, and ismeasured in lbf or N, and displacement is shown on the horizontal axis, measured in mm or

inches. Quadrant A displays the shock’s force as it is accelerated in bump, quadrant B as it isdecelerated in bump, C as it is accelerated in rebound and D as it is decelerated in rebound. This

plot can be used to troubleshoot a shock you are having issues with, or to ensure hysteresislevels are at an acceptable level. Hysteresis occurs when the damping forces are higher as thedamper is decelerating compared to when it is accelerating, and will decrease the effectivenessof the shock. This effect can be seen in the next graph, where the damping forces in quadrant Bare higher than in quadrant A. Hysteresis is the primary reason that a shock should be valved to

be used in the middle of its adjustment range, as hysteresis is significant when you use thestiffest adjustment settings.



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Damper Dyno