FSD Frequency Selective Damping

FSD is the abbreviation of Frequency Selective Damping. It is the latest technology of KONI, specifically designed to combine the ultimate in comfort and road-holding.

When the emphasis of a car’s performance is on the best possible road-holding, a lack in ride comfort is an automatic consequence when using conventional shock absorbers. Not so with the KONI FSD technology!

The groundbreaking FSD technology has been designed and patented by KONI to end the compromise between comfort and road-holding. This new feature can be used as an integrated part of the hydraulic valving system inside the damper. Consequently no additional cables, sensors, or any other electronic devices are needed to operate this system.

It operates fully hydraulic and frequency selective and is therefore an economical and effective solution to improving a car’s handling. It will give Ride and Handling Engineers a constructive, additional variable in fine-tuning the car’s behaviour.

Basically, comfort and handling can be split in two different frequency areas:
> For comfort, with the suspension moving in a high frequency area (± 10 Hz), asking for low damping forces.
> For handling, with the suspension moving in a low frequency area (± 1 Hz), asking for high damping forces.

If you are able to change the damping force level in relation to the frequency of the movement, you create the possibility to solve the conflict in terms of comfort and handling ever present in conventional dampers.

The KONI FSD technology does just that!

How does it work?

In standard shock absorbers the main damping characteristic is defined by the oil flow going through the piston assembly. (1)

Combining it with the FSD feature, KONI added a special valve (2), which controls an oil flow parallel to the one going through the piston rod. (3)

This parallel oil flow is closed by the FSD feature, giving a rise in damping force almost linear to the time that the piston is moving in one direction.

Put simply: the FSD feature is a hydraulic amplifier that delays the build up of pressure. One could say that an extra tuning option has been created in order to get the best possible combination of handling and comfort.

Since it is an integrated part of the hydraulic valve system inside the damper, no additional cables, sensors or any other electronic devices are needed to operate an FSD damper.

FSD is the simplest and most economic way to significantly improve the ride and driving characteristics of every car. Certainly in comparison with costly systems which work on the basis of computer technology, complex electronics and sensors.