Porsche 911 Carrera 4 Cabriolet (2001)

All-Wheel Drive With Viscous Coupling

As in the previous Porsche 911 Carrera 4, the new-generation model uses an all-wheel drive system based on a viscous multi-plate clutch. The previous system located the viscous unit in the rear transaxle, which added weight to the rear. In the current 911 Carrera 4, Porsche located the viscous unit directly behind the front differential, which simplifies assembly and maintenance and moved some weight to the front. The front location allows Porsche to offer the optional Tiptronic S transmission in the Porsche 911 Carrera 4, because both the 911 Carrera and 911 Carrera 4 use the same transaxle.

Adding just 120 pounds (54 kg) to the standard 911 Carrera, the all-wheel drive system in the Porsche 911 Carrera 4 qualifies as one of the lightest such systems in the world. Accommodating the front differential and halfshafts for the Porsche 911 Carrera 4 model required minor modifications to the strut mounting position, as well as a reshaped fuel tank.

Variable Power Split

The all-wheel drive system directs torque to the front wheels at a rate of five-to-40 percent, depending on available traction and power applied. The viscous unit compensates for differing wheel speeds during cornering. The Porsche 911 Carrera 4 exhibits outstanding traction on all road surfaces. However, Porsche designed the system to offer superior handling on mainly dry road surfaces. The automaker did not intend the all-wheel drive system as an all-weather traction assistant.

Porsche Stability Management

Porsche equips the 911 Carrera 4 with the advanced Porsche Stability Management system (PSM) as standard equipment. Porsche added PSM to the 911 Carrera option list for 2000, and for 2001 it's available as an option on the Boxster and Boxster S models.

Using data from several sensor inputs, PSM can detect a loss of grip at the front or rear and reduce instability by applying braking to individual wheels and, if necessary, altering engine power. On slippery roads, PSM can help keep the Porsche 911 Carrera 4 going in the direction the driver steers.

The PSM system operates so quickly that most drivers likely will not feel it make corrections. The driver can disengage PSM with a dashboard switch. However, for safety, PSM will engage under braking and then disengage when the driver lifts off the brake. While confident in the system's ability as a dynamic handling aid, Porsche cautions drivers that PSM cannot counteract the laws of physics.

Aluminum Suspension Components

Porsche optimized the new-generation 911 Carrera platform for both the rear-wheel drive model and the all-wheel drive Porsche 911 Carrera 4. The two models therefore share powertrains, suspension, and steering systems. Four-wheel independent suspension features a Porsche-optimized MacPherson-strut design in front and a multilink setup in the rear, both with aluminum suspension components to reduce unsprung weight. Front and rear stabilizer bars and gas-charged shock absorbers provide flatter cornering. Standard power rack-and pinion steering yields a quick 2.98 turns lock-to-lock and a tight 34.8-ft. (10.6-meter) turning circle.

A "staggered" wheel/tire array (wider wheels and wider, lower-profile tires on the rear) contributes to more neutral handling in the Porsche 911 Carrera 4. The standard aluminum alloy wheels measure 17 x 7 inches in front and mount 205/50 ZR17 tires; the 17 x 9-inch rear wheels mount 255/40 ZR17 tires. An optional 18-inch wheel/tire package enhances the already sharp handling and offers a choice of different wheel designs.

Racecar-Derived Brakes

The Porsche 911 Carrera 4 stops with four-wheel vented disc brakes with ABS 5.3 anti-lock control. Derived from the Porsche GT1 racecar, one-piece brake calipers reduce unsprung weight and heat. The front discs measure 12.5 inches in diameter and 1.1-inch thick (318 mm x 28 mm). The rear discs measure nearly as large - 11.8 inches in diameter and 0.95-inch thick (299 mm x 24 mm). The cross-drilled rotors dissipate heat to maintain braking performance and brake feel even under hard usage. (Porsche re q u i res brakes to provide 25 consecutive full-force stops without fade.)

Two Transmissions

The Porsche 911 Carrera 4 offers a choice between a precisely-shifting standard six-speed manual and the optional Tiptronic S five-speed automatic transmission. The six-speed manual features a dual-mass flywheel for low vibration and a hydraulic clutch for consistent performance.

With the advanced Tiptronic S, the driver can place the shift lever into "D" and let the transmission do the shifting, or shift into "M" and control gearshifts with steering wheel-mounted thumb switches. In automatic mode, Tiptronic S uses one of five programmed shift "maps" to respond to the driving style. For example, during leisurely driving, Tiptronic S will upshift early to provide a quiet ride and the best fuel efficiency. Quicker stabs at the gas pedal will call up a sporty shift program, which holds each gear longer for crisp response and power.

Even while in automatic mode, the computer-controlled Tiptronic S responds like a driver working a manual transmission, downshifting or holding lower gears when cornering and driving on hills. Tiptronic S also allows the driver to select manual mode by pressing an up- or downshift button, even with the shift lever in the "D" position.

Innovative Safety Technology

With the high performance potential of the Porsche 911 Carrera 4 comes a high level of occupant protection. A patented crumple zone body structure protects a reinforced passenger compartment. All new Porsche models include dual front airbags plus the Porsche Side Impact Protection System that includes boron-steel door reinforcement beams, energy-absorbing door panels, and door-mounted side airbags. The 30-liter capacity sidebags provide protection for the chest, head, and pelvis.

In the Porsche 911 Carrera 4 Cabriolet, the boron-steel reinforced A-pillars and windshield header combine with an automatic-deploying supplemental rollover structure to reduce the risk of injury in the event of a rollover accident. The optional Park Assist feature audibly warns drivers of obstacles behind the car.

Luxuriously Equipped

Reflecting its evolution into a grand touring sportscar, the Porsche 911 Carrera 4 comes with many standard luxury features:

• Power sunroof (Coupe)
• Automatic climate control with dust/pollen and activated charcoal odor filters
• AM/FM cassette stereo system
• Power windows with one-touch up/down
• Partial leather seats with power recline
• Leather-covered telescoping steering wheel
• Remote locking system
• Anti-theft system with engine immobilizer and alarm
• Heated windshield washer nozzles
• Heated power sideview mirrors

Available GPS Navigation

Notable options include the Porsche Communication Management system, which integrates controls and displays for Global Positioning Satellite (GPS) navigation, onboard computer, and climate control. A five-inch (diagonal) LCD color screen displays all functions. Litronic high-intensity gas-discharge headlights, available in option packages, increase lighting range and improve edge and side lighting for safer cornering.