||2-door coupe, production car
|Miles Per Gallon:
||355 bhp @ 6600 rpm
||295 lb-ft @ 4600 rpm
||f: 58.6 / r: 60.9 in
||--.- sec @ --- mph
|Braking, 60-0 mph:
|Nürburgring Lap Time:
The fabled wide-body, four-wheel-drive versions of the Porsche 911 Carrera return for the 2006 model year in the guise of the 911 Carrera 4S. The Carrera 4S features flared wheel arches to accommodate a widened track, larger wheels and tires and four-wheel-drive powertrains that give the venerable Porsche 911 additional dimensions of dynamic stability, especially in inclement weather conditions. As a further development of this newest generation of Porsche’s four-wheel-drive 911 Carrera,the 2006 911 Carrera 4S is equipped with enhanced Porsche Stability Management (PSM) technology featuring two new braking system improvements that have been engineered to provide the shortest possible stopping distances, a dynamic category in whichall Porsche vehicles are among the best in the world.
Nearly 2 inches wider
The four-wheel-drive versions of the Porsche 911 Carrera are nearly two inches (1.73 inches or 44 mm) wider than their two-wheel-drive counterparts. This extra width is needed to cover the wheels that are part of the enhanced four-wheel drive system.
Meanwhile, the 2006 Porsche 911 Carrera 4S is equipped with 19 x 8-inch front wheels with 235/35 Zrated tires and the huge 19 x 11-inch rear wheels with 305/30 aspect Z-rated tires.
With its powerful 355-hp, 3.8-liter “boxer” six, the 2006 Porsche 911 Carrera 4S sprints to 60 mph (96 km/h) in a mere 4.6 seconds and closes in on 99 mph in just 10.8 seconds. Top speed on the test track is 179 mph (288 km/h). The Tiptronic S version accelerates to 60 mph and 96 km/h in 5.0 seconds and reaches 99 mph and 160 km/h in 11.7 seconds. Top track speed is 174 mph (280 km/h).
All-wheel drive for extra driving dynamics
Porsche’s four-wheel-drive system uses a viscous multiple-plate clutch to send power to a central driveshaft that feeds a front differential to turn the front wheels with between 5 and 40 percent of the engine’s torque. This system of power distribution provides enhanced directional stability and balanced power and traction through turns and on slippery surfaces.
Such a viscous system exhibits outstanding cooling, even under high loads, and also is able to handle large changes in engine torque, for example, under all-out acceleration. The viscous coupling also reduces power loss due to friction between the clutch plates, adds only 110 pounds (50 kg.) of weight to the vehicle, needs no maintenance and reduces potential drivetrain distortion under extreme braking.
Torque split to the front wheels automatically adjusts between 5 and 40 percent to maintain superior traction. By sending no more than 40 percent of power to the front wheels, the four-wheel-drive 911 Carrera models exhibit dynamic characteristics similar to the rear-drive versions, so they will not understeer or “push” toward the outside over the front wheels in turning maneuvers.
Porsche Stability Management
Porsche Stability Management (PSM) coordinates data from various sensors to detect any loss of grip and helps the driver maintain stability by applying braking to individual wheels and, if necessary, by reducing engine torque.
The latest iteration of PSM benefits from advanced anti-lock brake sensors that take their readings not from conventional wheel pulses but from multi-pole seats fitted directly on wheel bearings. These improved signals allow more precise processing and control. Instead of conventional shaft valves, linear solenoid valves adjust brake pressure with nearly infinite precision. Another PSM enhancement allows for more control by the enthusiast driver. PSM can be turned off via a switch on the dashboard. In an earlier generation, PSM automatically reactivated whenever the brake pedal was depressed, but this latest version reactivates only when the pedal is pushed hard enough to activate the anti-lock system on at least one front wheel. For the enthusiast driver, this change allows more dynamic freedom, including slight use of the brakes in curves.
In regard to the enhanced braking system on the four-wheel-drive Coupes, one of the new functions “pre-fills” the brake system when the driver suddenly pulls his or her right foot off the accelerator. Because such a reaction by the driver is characteristic of an upcoming emergency braking maneuver, the systeminstantaneously pumps brake fluid from the PSM hydraulic unit to the brakes at each corner of the car. This eliminates the “air lag” between the brake pads and the brake discs so the pads already are directly next to the discs by the time the driver presses down hard on the brake pedal.
The new pre-filling pump activates within 40-60 milliseconds after the driver releases pressure from the gas pedal. As a result, brake pads are in their optimum position for maximum braking within 100 milliseconds of the driver’s reaction. To discern the significance of this figure in regard to shortening stopping distances, consider that even a professional racing driver usually takes 150 milliseconds to move a foot from the gas to the brake pedal. Testing has demonstrated that all drivers, regardless of their skill level, gain 40 and 80 milliseconds in braking application from this system.
The second new function of the enhanced PSM system hastens the build up of pressure in the braking system when the driver presses down on the brake pedal quickly but with less than full force. The system thus can reach the anti-lock braking threshold more quickly, providing maximum braking power and shortened stopping distances.
This new system also offers the experienced enthusiast driver the option to modulate the brakes under extreme dynamic driving conditions. For example, should the driver stop increasing pedal pressure or even reduce the pressure exerted on the brake pedal, any additional pressure built up by the system also is reduced.
However, this “pressure booster” aspect of the enhanced braking system does not always cut in. For example, if the driver already is pressing down on the brake pedal hard enough for optimum stopping power on all four wheels, any further increase in pressure would be unnecessary and the function therefore remains inactive. It also is inactive when the “Sports” button — part of the optional Sports Chrono Package Plus — is active and the PSM has been switched to its “off” position.
Porsche Ceramic Composite Brakes available
To further enhance braking power, Porsche Ceramic Composite Brakes are available as an option on the 2006 Porsche 911 Carrera 4S. Ceramic composite brakes were developed for high-level motorsports competition and were first used on a road car in the Porsche 911 Turbo. Instead of metal, the 13.78-inch (350 mm) brake discs are a ceramic composite material — carbon impregnated with liquid silica, then hardened into a very rigid, lightweight and non-corroding brake disc that weighs half as much as standard steel discs. This reduces unsprung weight and enhances dynamic capabilities.
Special high-friction brake linings are used to provide amazingly high and consistent levels of friction during application. Because of their extremely hard surface and freedom from corrosion and the damage it can cause, ceramic brakes reduce brake pad abrasion. They also provide maximum stopping power even inwet conditions.
Porsche Active Suspension Management
Porsche Active Suspension Management (PASM uses active damping to provide two suspension system settings, one designed for an athletic yet comfortable ride and the other for performance driving situations. By pressing a button on the center console, the driver can switch from “PASM Normal” to “PASM Sport.” Even in normal mode, the PASM suspension lowers the car by 0.39 inches (10 mm) compared to the standard 911 Carrera or 911 Carrera 4 Coupe suspension setup. Whenswitched into its Sport setting, PASM activates a firmer damper control map to provide extreme agility and dynamic control that minimizes body roll. In testing at Germany’s famous Nürburgring racing circuit, the PASM Sport setting produced lap times an average of five seconds faster than with the standard suspension setup.
Powerful 3.8-liter engine
To create the more powerful 3.8-liter engine that provides 355 (SAE) horsepower for the 2006 Porsche 911 Carrera 4S, engineers did more than simply increase the bore diameter by 0.12 inches (3 mm). They changed the intake manifold and modified the intake camshaft lift pattern. Injector angles were changed to enhance fuel flow to the center of the combustion chamber. This enhanced fuel/air mixture also reduces exhaust emissions, even after a cold start, and increases torque throughout the power curve. A short-pipe exhaust manifold for the 911 Carrera 4S engine further reduces emissions.
The intake system was further designed to provide less resistance. A Helmholtz resonator is used to enhance acoustics. This provides more than 18 cubic inches (0.3 liters) of additional resonance volume between the hot-film air mass meter and the throttle butterfly and is activated between 5,000 and 6,000 rpm to reduce oscillations in intake sounds. Porsche has applied for a patent for this technology that provides a deep, throaty sound without aggressive peaks.
Higher combustion forces produce more power but also more torsional crankshaft vibration, so Porsche engineers integrated a vibration damper in the pulley at the end of the crankshaft. While conventional vibration dampers are made of cast iron, Porsche engineers devised an aluminum damper that reduces weight by some 3.3 pounds (1.5 kg) while controlling vibrations to a leveleven lower than the 3.6-liter engine.
6-Speed manual transmission
To deal with the 911 Carrera 4S engine’s 295 pound-feet of torque, Porsche upgraded its six-speed manual transmission, which is also used in the 911 Carrera 4 Coupe. Steel rather than brass synchronizing rings as well as thick shafts and wide gears provide strength, yet the transmission’s weight is kept down by using extra-thin aluminum in the oil chamber walls. The transmission’s internal architecture saves weight and reduces splash effect and flow losses, thus increasing the gearbox’s efficiency. The gearbox uses wear-resistant carbon-coated first, second and third-gear synchronizing rings, with triple synchronizing for first and second gears and double synchronizing for third gear while retaining single synchronizing for gears four, five and six. The driver benefits from reduced force and shorter travel in gear changes.