Shock dyno tuningA shock dyno is a great tool for verifying that like dampers are delivering like performance. When dampers have rebound and compression adjustments, a shock dyno can be used to plot the force versus piston velocity curves. Although dampers are always modeled to deliver force as a function of piston speed, the acceleration of the piston also plays a slight factor as shown by the full cycle loops on the plots.


To control the recoil and resonance of the spring, the damper transforms the springs’ mechanical energy into heat. This is accomplished by forcing a perforated or valved plunger through oil in a tube. Changing the valving, the size of the plunger, or the pressure of the nitrogen charge can all affect the performance. There is not one magic combination that works well on every car. Overall weight, intended use and corner weights are just some of the factors that will affect the way the appropriate dampener is designed. The easiest demonstration of this could be the comparison of a time-attack car and a baja truck. Both are competitive vehicles, but the Baja trucks may require suspension travel measured in feet while the travel on the time attack car might be measured in centimeters.

DampersDampers begin life as an alloy cylinder that undergoes extensive machining, surface treatment and assembly to reach its final stage. Here, a set of Eibach Multi-Pro dampers undergo final assembly.

Adjust Must Plus

KW coiloversJust like the design of the dampener, the adjustability of a coilover can vary just as much. Coil-over kits can allow for height adjustment, dampening adjustment, spring seat loading adjustment and nitrogen charge adjustment. The threaded body of a coil-over system can be used to adjust the height and load on the springs. Some designs use the base perch to enable only height adjustment and a second perch to adjust spring seat load. Other designs only allow for height adjustment via the spring perch. While single-perch-adjustable designs will be adequate for corner balancing, it will not provide for spring pre-loading adjustments.

Damper adjustments run a gamut of capabilities. It’s not uncommon to see one coilover with a knob that delivers three damper settings while another offers 32 clicks from a single knob. Another damper may have four sepate knobs or dials to make four-independent damper adjustment. These directions represent compression, rebound, high-speed compression, high-speed rebound and combinations of the four. As an example a 4-direction adjustable coilover boasting a 32-way graduated adjustment range results in a dampener that can be set in 1,048,576 configurations at each corner.

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