Fortune Auto New Zealand

Fortune Auto New Zealand

title

FORTUNE AUTO VALVE TECHNOLOGY

  
Digressive Piston Basics
 
Fortune Auto dampers utilize Digressive and Ultra Digressive piston technology. 
 
Digressive vs Linear Piston Technology  
 
Digressive pistons produce a valving profile that is not straight or constant. As shaft speeds increase (thinking hitting a large bump at high speeds) the rate that damping force is created tapers off considerably. Digressive piston design exhibits low flow rate at low shaft speeds that provides a lot of resistance and control. Then the resistance rate increases when shaft speeds increase. Finally at a preset point (higher shaft speeds) the force rapidly tapers or "blows off". This characteristic works tremendously well when going over large bumps or berms on a race track at high speeds

Read more: http://www.circletrack.com/techarticles/139_0307_shock_absorber_tech/linear_digressive_designs.html#ixzz38EDjSGsA

The digressive piston design has a low flow rate at low shaft speeds that provides a lot of resistance and control. The resistance rate increases with increased shaft speeds to a designed level and then tapers off. As the shaft speed continues to increase, the resistance stays uniform above a certain shaft speed. This "pop-off" characteristic works well for reducing the possibility of building excessively high amounts of resistance usually associated with sharp increases in shaft speeds due to running over bumps and holes in some racetracks.

Read more: http://www.circletrack.com/techarticles/139_0307_shock_absorber_tech/linear_digressive_designs.html#ixzz38EDjSGsA

The digressive piston design has a low flow rate at low shaft speeds that provides a lot of resistance and control. The resistance rate increases with increased shaft speeds to a designed level and then tapers off. As the shaft speed continues to increase, the resistance stays uniform above a certain shaft speed. This "pop-off" characteristic works well for reducing the possibility of building excessively high amounts of resistance usually associated with sharp increases in shaft speeds due to running over bumps and holes in some racetracks.

Read more: http://www.circletrack.com/techarticles/139_0307_shock_absorber_tech/linear_digressive_designs.html#ixzz38EDjSGsA
 
The opposite of digressive is linear. With a linear plot the rate of damping force generated varies very little. The damper exhibits a consistent feel through the entire stroke range. For example if you hit a specific size bump on the street or curbing on a race track you will feel the force of the impact. If you were to hit a bump that is twice as big, the impact feel will be twice as large. This is the opposite of a digressive piston.

 Ultra Precise Shim Stacks

Shims are deflection disks that cover up the port holes on a piston. They regulate the fluid flow which generates the force found in a damper. "Valving" or "re-valving" of a shock is accomplished by using a variety of shims that will ultimately provide enough resistance and damping ability for a particular application. Minute differences in the shims' diameter and thickness are very critical; just a thousandths of an inch of variation in the dimensions can change a damper's force profile up to + or - 25%. The shims' consistency is crucial in matching shock absorbers to one another. Generation 5 dampers utilize a high-grade shim material made of Sandvik knife grade steel, ensuring precision matched dampers.