911 SAFETY DEVELOPMENT
It’s not just about the thrill of the drive, as Porsche has always imbued its Neunelfer with impressive levels of safety. Total 911 delves into the history
Whether you like your 911 in air- or water-cooled flavours the engineering integrity and motorsport pedigree never fail to stir the soul, but there’s another aspect of development that rarely merits much in the way of consideration: safety. Although it’s probably not at the forefront of our minds when attacking a favourite ribbon of Tarmac, it shouldn’t be dismissed, the 911 long having blended driving thrills with a focus on keeping those behind the wheel in one piece. Recent years have seen sophisticated electronics play a more prominent role in the safety equation, but even the very earliest models didn’t ignore such a crucial element of car design. For example, way back in 1963 the adoption of rack and pinion steering not only provided vastly superior levels of feedback and tactility but its engineering demonstrated that Porsche understood the need to protect the driver should the worst happen. The steering gear was located in the centre of the car and connected to the steering wheel via a three-part linkage with two universal joints – in the event of a frontal collision the wheel would be directed away from the driver. And then there were the improvements to braking performance with the adoption of dual-circuit brakes for the ‘A’ series and the wider use of ventilated discs. Those earliest years also saw a greater focus on minimising the 911’s more undesirable handling traits, and if adding a pair of 11kg iron weights to the front bumper was a decidedly inelegant engineering solution (one that Porsche would rather not be reminded of) it showed their awareness of the need to improve stability. Ultimately those ‘bumper reinforcements’ were ditched as Porsche focused on improving weight distribution in more traditional ways, as well as making constant improvements to the suspension set-up and geometry. And we can’t leave the 1960s without mentioning the Targa, a model that became an iconic part of the line-up thanks to the strength-imparting roll hoop. The 1970s saw more gradual developments in safety with closer attention being paid to the integrity of the body shell, but more visible improvements would also arrive. For G-series cars Porsche introduced cabin changes including safety steering with a padded boss and the high-backed ‘tombstone’ seats with integral headrests. With safety becoming an ever more important consideration for buyers – not to mention the increasingly stringent legislative requirements – it’s no surprise that the 1980s saw Porsche adopt plenty of improvements. For example, 3.2 Carrera owners now benefitted from numerous safety devices, from an interior that featured deformable materials for dashboard controls to flame-retardant upholstery. Greater attention was also paid to the body shell, which boasted more extensive front crumple zones and safety locks for the doors that prevented them bursting open in an impact, while 1985 saw Porsche fitting super-highstrength steel beams in each door for side-impact protection. This brings us to the model that would finally end the 911’s image as something of a motoring anachronism. The 964’s history and development has been chronicled within these pages before, but suffice to say that it marked the advent of the thoroughly modern Neunelfer, not just dynamically but also in terms of safety. Not only did it feature a far more ergonomic cabin that was less distracting and irksome for the driver, but also a steering wheel and dashboard that boasted air bags. It wasn’t the first Porsche to feature them – Us-bound 944 Turbos got them in 1987 – and they wouldn’t become standard on European 964s until the early 1990s, but it was the start of an intensive period of safety development that continues to this day. The 964 was the first regular model to be fitted with anti-lock brakes and the traction-enhancing benefits of an electronically controlled four-wheel-drive system.
It was a turning point from which Porsche never looked back, each succeeding generation incorporating ever more complex and effective safety systems. Indeed, the 996 brought a new innovation with the Porsche Side Impact Protection system (POSIP) which paired the door protection beams with a side air bag for each occupant. It was also the first appearance of Porsche Stability Management (PSM), combining the anti-lock brakes, traction control in the form of Anti-slip Regulation (ASR) and an automatic brake differential; if loss of traction was detected the system braked individual wheels to restore stability and cut engine power if required. The early 2000s also saw the addition of seat belt pretensioners and force limiters, a pyrotechnic system that worked in conjunction with the air bags to tighten the seat belts, operating in around 20 milliseconds. And more traditional safety methods weren’t ignored, the body shell constructed from high-strength and Boron steels along with tailored blanks in key areas for maximum rigidity. Three separate load paths within the shell distributed crash forces around the passenger cell, while Cabriolet drivers were protected by a pair of spring-loaded bars located behind the rear seats which deployed automatically if a potential roll over was detected. It was reassuring stuff, extended for the 997 generation with features such as tyre pressure monitoring and additions to the PSM system for C4 models. For those, sudden release of the throttle primed the brakes by raising the pressure in the brake lines, bringing the pads into light contact with the discs, while a brake assist function provided maximum retardation in the event of an emergency stop. 997s also adopted two-stage operation of driver and passenger front air bags, the force of deployment differing depending on the severity of the crash, and by now Porsche used an organic-based propellant that made the air bag units smaller and lighter. Further developing the POSIP system it now featured two side air bags, one in the seat backrest for thorax protection and a head air bag deploying from the top of the inner door panel; eight litres in volume each (the 996’s single bags were 30 litres) they promised maximum protection, while Cabriolet and Targa models boasted specially shaped items to ensure protection when the roof was open. By the time the 991 arrived in 2011 these systems were embedded as a key part of the safety arsenal, but that didn’t stop Porsche making further tweaks to the POSIP system – increasing the volume of the thorax and head air bags to 10 and 15 litres respectively – and introducing new tech in the form of Porsche Active Safe. Optional for Pdkequipped cars, you got an active cruise control system incorporating a radar sensor to monitor the speed of the car in front. Not only could it increase or decrease speed accordingly, including braking to a standstill, but the system also provided audible and visual warnings if it detected a decrease in distance to the car ahead that signified an accident risk. It’s all very clever stuff, and the sort of technology that most of today’s drivers take for granted, but for owners of a 911 it’s the culmination of more than five decades of effort by Porsche to ensure its most famous sports car has always been as safe as it is thrilling. It’s safety systems like the ones mentioned above which ensures that of the one million Porsche 911s produced since 1963, more than 70 per cent are still on the road today.
“It was a turning point from which Porsche never looked back, each succeeding generation incorporating ever more complex and effective safety systems”