Making It Stick Part 6 - Monotube Dampers

Tomorrow's Dampers Today

Although not yet available to the common consumer, new developments in damper technology are trickling down from Formula 1, WRC, and other high-tech racing series. In a few years these design features will become more affordable and available at the enthusiast level. One such development is a unique solution to the issue of gas reaction forces in monotube dampers. Ohlins and Sachs have developed a design in which the shaft goes through the entire damper body, gas chamber and all. This takes shaft displacement out of the equation completely and negates the gas reaction forces. The gas chamber now functions as it was meant to, pressurizing the oil and reducing cavitation-without adding preload. In addition, Ohlins, Koni, and Sachs have new designs that use a very precise and complex array of valves and internal chambers to allow damping adjustment at up to five different piston speeds.

Another new development in street performance dampers are self-adjusting valves. At low piston speeds, self-adjust valves produce a lot of damping to control body motion with little damping at high-piston speeds making for a smoother ride on big bumps. There are currently two types of these valves: the inertia valve and the Koni Frequency Selective Damping (FSD) valve.

Inertia valves use a weighted sliding valve that opens and closes at different rates of piston movement. Edelbrock shocks have an inertia valve that controls rebound damping while Nismo uses an inertia-type valve on their S-Tune Altima suspension that affects compression damping.

The Koni FSD system uses a bypass valve to put fluid pressure to the rear of the rebound damping control valve. At high piston speeds the bypass allows fluid to flow behind the main valve, overcoming its spring preload and allowing it to open easily. This greatly reduces rebound damping. At lower piston speeds not enough fluid can flow through the bypass and the valve stays closed so rebound damping levels stay high.

Stay tuned, in the next installment we will talk about how dampers affect vehicle dynamics and what you can do with them to improve performance on your own car.

Other Installments:

Making It Stick Part 1: Four basic steps to better handling

Making It Stick Part 2: Four more steps to better handling

Making It Stick Part 3: It's all in the geometry

Making It Stick Part 4: More lessons in suspension geometry

Making It Stick Part 5: Damper fundamentals

Making It Stick Part 6: More advanced dampers

By Jay Chen

Enjoyed this Post? Subscribe to our RSS Feed, or use your favorite social media to recommend us to friends and colleagues!