Us Atom shock choices....

[Jammer]

Option #2    Race Products30 SeriesFigure 1: general layout of the mono tube damper.
  Principle
Unlike the twin-tube damper, the mono-tube shock has no reservoir tube. There is still a need to store the oil that is displaced by the rod when entering the cylinder. This is achieved by making the oil capacity of the cylinder adaptable. Therefore the cylinder is not completely filled with oil, the lower part contains nitrogen gas under 20 to 30 bar. A floating piston separates gas and oil.

When the piston rod is pushed in, the floating piston is forced down by the displacement of the piston rod. The oil below the piston is forced to flow through the piston generating the bump damping.

Principle of the damper in bump.
The monotube damper has a piston with shim stacks on both sides. In the piston 12 holes are drilled. Six of them are used for the bump damping, while the other 6 are used for the rebound damping. On the piston different shim stacks can be mounted. When the damper is compressed the oil pressure above the cylinder is decreasing. Due to this pressure difference the oil will flow through the piston. When the piston is compressed at higher speeds the pressure difference over the piston will increase. Due to this the preloaded shim stack will open. During the bump stroke the pressure above the piston will decrease. The pressure of the nitrogen has to be high enough to take care that the pressure above the piston remains higher than atmospheric pressure. If this is not the case air will be sucked in above the piston. If this happens the damper can not work properly anymore.

Principle of the damper in rebound.
The principle in rebound is almost the same as the situation in bump. When the damper is extended by the spring of the car, first the oil will flow through the constant holes made in the piston. When the speed of the damper increases the pressure difference over the piston increases and the shim stack will open and more oil flow through the piston. When the damper rod is being extended there is less rod displacement in the damper which causes the nitrogen to expand.

 
Adjustment mechanism in bump.
The adjustment mechanism of the 30 series dampers works by increasing the pre load on the shimstack. As the pre load is increased the shimstack will open at a higher-pressure difference over the piston and creating higher damping forces. To adjust the bump forces first the damper has to be dismounted on one side. Then the following steps need to be carried out:
 
1.  Take tool 1037 74 01 04 or a tool of similar dimension to depress the adjuster button.
2.  Hold the shock body where the piston rod emerges from the cylinder. Depress the button fully and hold it down while adjusting.
3. The adjuster has 10 distinct stops (clicks) each of which marks an adjustment position.
4. The shocks may have been adjusted previously. Check if the shock is in the zero-position by turning the piston rod clockwise until the zero-stop is felt. Do not force in this position.
5. To increase the bump damping, turn the piston rod counter-clockwise.
6.  While the button is depressed, do not turn the piston rod further, otherwise correct adjustment will be disturbed. Release the button and make sure that the adjusting button springs fully back into position. As soon as the button is back in position, the piston rod may be turned freely.
 
Figure 2: bump adjustment 
Adjustment mechanism in rebound.
The rebound adjuster requires a pin with an outside diameter of 3 mm or a 2.5 mm Allen key. If higher rebound forces are desired, put the adjuster pin next to the minus sign and turn the pin towards the plus sign. This is one sweep of adjustment. From the minimum position there is a total adjustment range of 6-8 sweeps. There are no specific clicks of adjustment to mark the adjustment position, the rebound adjuster can be placed at any position in the adjustment range. Do not force the adjuster as binding may result.

[Jammer]

Option # 3


Introduction
The 2812 MKII series shock absorber or damper is a monotube construction, charged with high-pressure nitrogen gas. Specifically designed for competition purposes, it is fully adjustable while fitted on a car, in both bump (compression) and rebound (extension). Its precision adjustment mechanism allows the maximum control possible over the damping forces generated.
On modern racing cars, the mean piston speeds the dampers are running at are very low. As a result, precise control over the damping forces at low speeds is very important. This in turn means that very small flows of oil have to be controlled. In racing-damper designs, a needle valve is used that tries to achieve this. Such a simple mechanism has many drawbacks, the most important being a high sensitivity to; manufacturing tolerances, oil viscosity (and thus temperature variations) and damage to the (needle) valve seat. Regular performance checks must be carried out and the only way to make such dampers perform as you want them to, is to set them on a damper dyno.

For KONI, such deficiencies and the workload they create are not acceptable. Repeatability, consistency and ease of use are a must for any racing damper. To achieve this, the 28 series uses a superior and advanced adjustment cartridge that controls the opening and closing of valve loaded parts. Distinct stops (clicks) assure that each port can only be either open or close. Thus total repeatability of performance is engineered into the damper and the need for calibration on a damper dyno is eliminated.
Two such mechanisms are contained in the main piston, one for bump and one for rebound. They operate totally independent of each other. For both bump and rebound 8 adjustment positions are available, generating a total of 64 predefined damping curves.
By having all forces generated by the piston itself, the control over the damping forces is very precise. A separate reservoir is not needed to accommodate the bump adjuster. This makes the installation simple, lightweight and clean.