Uncover the innermost workings of the new Cayman S
The new Cayman S is rapidly approaching Porsche showrooms and will be unleashed in early 2006.
The Cayman S is powered by a specially developed mid-mounted engine featuring VarioCam Plus technology. Ideally positioned at the heart of the car, the 3.4-liter flat-six unit develops 295 hp. The horizontal cylinder layout creates a low center of gravity, which enhances handling and agility. Key characteristics include potent delivery, free-revving response, excellent cylinder charging, smooth running and exceptional outright performance. This optimum combination of output and layout is key to the power and agility of the car.
Maximum torque of 251 lb.-ft. is available from 4,400 - 6,000 rpm. This broad band of torque is in part a result of the resonance induction manifold with twin-flow intake pipe. Also involved is VarioCam Plus, a variable valve control technology which generates additional torque at lower engine speeds. Other benefits include better fuel economy and lower exhaust emissions.
VarioCam Plus combines variable valve timing with two-stage lift on the inlet side. The resulting benefits include greater power and torque at all engine speeds, as well as smoother running, better fuel economy and fewer exhaust emissions.
Essentially, the system creates two engines out of one, switching seamlessly between them as driver inputs change. All operations are controlled by the engine management system, which ensures rapid acceleration and smoother running.
The two-stage valve lift mechanism on the inlet side includes a series of electro-hydraulically switchable tappets. Each of the 12 tappets consists of two concentric lifters, which can be locked together by means of a pin at the request of the engine management system. When the tappets are locked, the outermost ring – which is driven by two large-profile cams – is in direct contact with the valve. When the pin is removed, the innermost lifter – operated by a smaller cam lobe – has sole influence over the amount of valve lift. The timing of each valve is controlled by means of an electro-hydraulic rotary vane adjuster at the head of each inlet camshaft.
To improve responsiveness when starting from cold, VarioCam Plus will raise the amount of lift and retard the valve timing. At medium revs and minimal load, the valve lift is lowered and timing advanced to help minimise fuel consumption and emissions.
To achieve maximum power and torque, the lift is raised and the timing advanced.
The Cayman S is available with the option of five-speed Tiptronic S. This versatile system combines automatic transmission with the option of manual gearshifts.
For manual control, simply slot the gear selector into the manual gate and use the gearshift controls on the steering wheel. Press up to change up, and down to change down. Gearshifts are performed in around 0.2 seconds with virtually no interruption in drive. The action is comparable with that of a manual gearbox.
Switch to automatic, and you can still change gear by hand using the rocker controls on the steering wheel. This race-derived function is particularly useful when performing an overtaking maneuver. If there is no manual input for a period of eight seconds, the system will revert to automatic mode. The drive position and gear selection are displayed at all times on a dedicated cockpit display.
In automatic mode, Tiptronic S can choose from a range of shift points for every gear. The standard gearshift pattern, designed for maximum fuel economy, can be varied up to a dedicated ‘Sport’ configuration for optimum high-performance driving. Each gearshift point is automatically selected based on current driving style and road conditions. Within a short space of time, you’ll develop a feel for the system and begin to influence gearshifts using the throttle alone. The benefits of Tiptronic S are particularly apparent when exploring the car’s performance. Even in automatic, the rapid gearshift action enables exceptional agility from the car.
Other useful functions include a warm-up program, automatic selection of the ‘Sport’ gearshift pattern via rapid throttle inputs, gearshift suppression during cornering maneuvers, automatic downshifts under heavy braking, an incline sensor (improves uphill acceleration and downhill engine braking), and automatic upshifts when traction is threatened under braking in the wet.
If the optional Sport Chrono Package is enabled, the gearshift action is even more direct and sporty. If you happen to be driving in manual mode, automatic upshifts are prevented.
The Motronic ME7.8 engine management system is the primary source of control for all engine-related systems and processes, e.g., ignition and fuel supply. It is an essential prerequisite for enhanced performance in all operating conditions. The electronic throttle is not only more precise, it can modulate the volume of incoming air to compensate for sudden load changes (such as when lifting off the throttle before braking). Electronic engine management provides smoother delivery from a standing start as well as a less intrusive rev limiter action. It also coordinates the various sub-systems within the standard Porsche Stability Management (PSM), like anti-slip regulation (ASR) and the automatic brake differential (ABD). Other important functions include coordination and control of the optional Tiptronic S transmission, stereo Lambda sensors, variable valve timing (VarioCam Plus) and cylinder-specific knock control.
A mid-engined layout with low center of gravity provides the perfect foundation for agile, dynamic performance. Combined with a rigid body shell construction, the potential benefits are multiplied. All it takes to reap those benefits and apply them to the road is an appropriate chassis concept.
On the Cayman S, that chassis is based on McPherson-strut suspension for both front and rear. A proven Porsche road and race technology, the effective combination of coil-over struts and lateral control arms is key to the character of the car. When designing the suspension, the absolute priority was to apply maximum drive to the road. This immediacy of response should also be matched by the quality of feedback and comfort.
To achieve those objectives, we’ve used a generous ‘track’ or distance across each axle. The springs, shock absorbers and anti-roll bars are rated for high-speed cornering. The use of lightweight construction techniques and materials helps to minimize sprung and unsprung weight. Virtually all moving parts on the axle assemblies are made from aluminum.
The resulting chassis is equally capable during high-speed maneuvers and in tight, twisting bends. There is no unwanted movement from the suspension, and little susceptibility to pitch and roll under cornering, acceleration and braking.
Performance is matched by exceptional active safety on every type of road. The stability of the car is extremely good, enabling a sensitive response. In simple terms, that means greater reserves of safety, regardless of load, as well as natural resistance to lift-off oversteer.