Saturday, 17 August 2013

Dynamic Stability & Traction Control

The Roadster NC generation has more advanced safety systems than previous models. One such system is called Dynamic Stabilty Control, and was designed to reduce accidents by helping the driver keep the car under control. The DSC system works with the ABS and consists of a speed sensor on each wheel, a steering angle sensor, a brake fluid pressure sensor, a control module (the brains of the operation), and a combined yaw rate & lateral acceleration sensor. DSC was standard on NC 2.0 models, and from NC2 onwards became standard equipment on all models.

When the system is switched on the control module constantly monitors data from each sensor and acts to correct oversteer and understeer situations by automatically cutting torque to a driven wheel and applying the brakes to one corner to restore stability and keep the car from skidding out of control. There are two dash lights associated with the system. When the DSC is activating the warning light on the dash will flash. The DSC system has a switch on the dashboard to turn it on and off, the default setting is on and even if you switch it off, the next time you start the car DSC will turn itself back on. If DSC is switched off, the "DSC OFF" warning light on the dash will be lit.

A Traction Control System (TCS) is incorporated into the DSC and works in a similar way. The wheel speed sensors on the rear wheels are monitored continuously and if they detect the wheels are slipping, torque is reduced and brakes applied until the wheels achieve traction. Traction control automatically adjusts engine power to get the best drive without wheelspin. If the system is activating the warning light on the dash will flash on and off and you'll hear the engine make a rumbling sound as it cuts back on torque. The TCS system can be switched off using the DSC switch, or in other words turning off Dynamic Stability also turns off Traction Control.

All Roadsters feature a 4 wheel anti-lock braking (4W-ABS) system as standard. The wheel speed sensor data is monitored by the ABS module which detects when a wheel is locking under heavy braking and regulates the brake fluid pressure to prevent this. The ABS system includes electronic brake force distribution (EBD). The EBD system uses a load sensor to detect when the car is carrying passengers and luggage and adjusts the brake balance between front and rear accordingly. This system effectively reduces braking distances.

Now I know some owners lament the loss of simpler times without sensors and electronic driver aids. The original 1980s Roadster never had such annoying intrusions they'll say, but I think if you ever have to take emergency evasive action and DSC/TCS/ABS/EBD saves you from an expensive accident and insurance claim, you'd change your mind. The videos below illustrate how these system work.