Volvo Four-C Suspension — Continuously Controlled Chassis Concept

Volvo’s Four-C, short for Continuously Controlled Chassis Concept, is a type of active suspension available on some Volvos starting in model year 2004 (North America).

But Fast Volvos Get “Advanced” Setting

The multi-mode suspension — for instance, the driver-selectable modes in a 2004 V70 R are Comfort,  Sport and Advanced — was developed by Volvo with input from Swedish suspension company Öhlins. Non-R cars get only two settings, Comfort and Sport.

In enthusiast circles, the system has a mediocre reputation, one complaint being rear-end side-to-side hop over rough patches of roadway, and 2004 models of Volvos supposedly suffering the most.

Sorry, No, They’re Not Cheap

Unfortunately, replacement 4C struts cost an arm and a leg, often topping $1500 for all four. I’m not talking about the whole job with labor but rather just the struts’ cost. This Volvo Forum struts post discusses where to find these special Monroe struts for relatively cheaply… around $1000 for all four.

Currently IPD has them on sale for $325 each, as of this writing. IPD is a great place to buy OEM Volvo parts. Please tell them MVS sent me. Thanks in advance.

4C Sensors Monitor Many Signals

The sensors provide about 500 reading impulses a second, measuring parameters such as:

• The car’s speed and acceleration
• Lateral acceleration (when taking a curve)
• The wheels’ suspension movements
• The steering wheel’s position and how fast it is turned
• The engine’s current (calculated) torque
• The degree of braking

Additional FOUR-C Information

The active chassis is based on a highly advanced technology known as FOUR-C (Continuously Controlled Chassis Concept). This system was developed together with Öhlins Racing AB. In FOUR-C, each shock absorber is regulated electronically and entirely individually. Damping is varied continuously with immense speed, from soft to hard in less than one twenty-fifth of a second. The driver does not even notice the change. Body and wheel movements are monitored continuously with the help of a number of sensors in the car. The sensors provide about 500 reading impulses a second.

Owing to the speed of the FOUR-C system, the car can even handle really difficult “washboard” surfaces without causing the wheels to lose their composure.

FOUR-C is optional on the Volvo S80. The system requires that the car is equipped with DSTC – Dynamic Stability and Traction Control – since the DSTC sensors provide some of the necessary information about the car’s behaviour.

The combination of FOUR-C and DSTC makes 2000s-era Volvos competent and extremely comfortable long-distance tourers – offering exceptional ride comfort allied to dependable, safe roadholding properties.