Ideal situation
Instability control. Taking it to the limit, safely and surely: The new Sport mode in
The red 911
Ickx has the powerful 911 firmly under control. The petite native of Belgium is one of the greats at the wheel. Her talent clearly runs in the family: Vanina Ickx’s father Jacky, for instance, won eight Grands Prix in his Formula One career. His name is even more hallowed in connection with the 24 Hours of Le Mans, where he took the overall title six times, four of them in a
Ickx flashes a brilliant smile as she lets the
Peglau is a suspension engineer. He and his colleagues were responsible for developing the PSM Sport mode. They spent two and a half years on the project, clocking countless kilometers on all kinds of surfaces—dry, wet, icy, snow-covered—and on all manner of racetracks, including the Arctic Circle Raceway. They didn’t rest until every parameter was so finely adjusted that the results met
“PSM Sport is not a drift mode,” says Peglau (42). The electronics do not take artificial measures to achieve and main-tain a certain sideslip angle. “This would rob drivers of their feel for the car, and give them a false sense of security about their skills. PSM Sport by no means takes control of the car out of the hands of advanced drivers.”
According to Peglau, one of the greatest challenges at the limits of performance is the transition from stability to instability. Developers call this “yaw acceleration,” which refers to the strength of the impulse that leads to oversteering. If this impulse is too strong, it’s hard to get the car back under control. And it’s precisely at this point that PSM Sport sets in, without any additional sensor systems. “We haven’t just simply raised the control thresholds,” explains Peglau. “What we’ve done instead is dampen the initial yaw acceleration. This allows us to create a gentler transition. As soon as the system recognizes that the driver has everything under control, it allows for greater freedom—the threshold values for traction control are raised and the PSM’s interventions in braking for stability are toned down. This approach turns stability control into instability control, so to speak, without distorting the basic character of the car.”
The aim was to enable drivers to experience the extraordinary driving dynamics of a
At the same time, the safety net is spread considerably wider in the background. If the driver encounters difficulties and the brake pedal pressure exceeds the activation threshold of the anti-lock brake system, PSM switches back on, either more or less quickly depending on the preceding pressure. This “emergency anchoring” function is already similar to PSM-off mode. PSM Sport mode gradually approaches PSM-on mode from 100 to 150 km/h. The only thing that can happen now, even at speeds above 150 km/h, is an intervention by the traction control system, although this depends on the level of grip on the driving surface.
“We might also say that PSM Sport takes the driver by the hand and leads him carefully up to PSM-off mode, because that option continues to be available, of course,” says Peglau. But it should remain what it has always been: the most extreme means of choice for the very skilled. Such as Vanina Ickx in the 911
By Klaus-Achim Peitzmeier
Photos by Heiko Simayer