TOP-DOWN TRACTION: THE 2004 911® CARRERA® 4 CABRIOLET

ATLANTA – Combining the classic lines and open-air appeal of the Porsche® 911 Carrera Cabriolet with the confidence of all-wheel drive, the 2004 Porsche 911 Carrera 4 Cabriolet offers the best of both worlds.

Based on the 911 Carrera Cabriolet, the 2004 911 Carrera 4 Cabriolet differs most in that its drivetrain powers all four wheels. It uses an all-wheel drive system based on a viscous multi-plate clutch located directly behind the front differential. Weighing only 120 pounds (54 kg), the all-wheel drive system in the 911 Carrera 4 Cabriolet qualifies as one of the lightest such systems in the industry.

The all-wheel drive system directs five to 40 percent of the torque to the front wheels, depending on available traction and power applied. The viscous unit compensates for differing wheel speeds during cornering. While the 911 Carrera 4 Cabriolet exhibits superior traction on all road surfaces, this was not Porsche’s original intent. Porsche designed the all-wheel drive system to handle the unexpected curves and bends in the roads.

To this end, Porsche also equips the 911 Carrera 4 Cabriolet with the advanced Porsche Stability Management system (PSM) as standard equipment. 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 911 Carrera 4 Cabriolet 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 the system provides dynamic handling aid, Porsche cautions drivers that PSM cannot counteract the laws of physics.

Subtle exterior differences distinguish the 2004 911 Carrera 4 Cabriolet from its rear-wheel drive sibling. These include plainly visible titanium-color brake calipers and a titanium-color “Carrera 4” logotype on the rear engine hood.

The 2004 Porsche 911 Carrera 4 Cabriolet comes with a fully automatic three-piece top that opens in a Z-configuration and folds down into a compartment behind the rear seat. Unlike most cabriolet tops that expose the inside of the roof lining when the top is retracted, Porsche’s Z-configuration keeps the inside of the roof protected at all times, takes up less space when the top if stowed, and provides better protection for the heated rear glass window when the top is down.

The Cabriolet top is made of a high-quality fabric, with a special plastic material between the outer and inner layers providing superior sound insulation and heat protection.

A light but stable aluminum frame helps keep the structure stable and resistant to ballooning, even at very high speeds, and applies tension to the section of the roof between the windshield and the first bracket. The top has been tested in a wind tunnel at speeds of nearly 210 mph (338 km/h) without problems.

The roof is fully automatic, operated by a hydraulic system and electric motors that lock the front roof bracket to the windshield frame. A microcomputer masterminds the smooth flow of all functions opens and closes the top in 20 seconds.

All 2004 Porsche 911 Carrera 4 Cabriolets come with both a standard wind deflector and an aluminum hard top. The wind deflector, made of two frames covered by a net fabric, extends over the area between the front seats and the supplemental safety bar cover and ensures a draft-free driving experience when the top is down. The wind deflector can be installed or removed in a matter of seconds and can be stored in the front luggage compartment.

The aluminum hard top is made from two shells riveted together and includes a parcel shelf that helps reinforce its structure. The hard top has a heated rear glass window, yet weighs only 71 pounds (32 kg), making it easy for a driver and passenger to install when they want the security of a hard roof over their heads.

Like the 911 Carrera Coupe, Cabriolet and Targa, the 2004 Porsche 911 Carrera 4 Cabriolet features Porsche’s 3.6-liter, six-cylinder, horizontally opposed “boxer” engine.

This engine employs Porsche-patented VarioCam® Plus technology and Motronic ME 7.8 engine management controls to provide power and efficiency. The liquid-cooled engine is rated a 315 horsepower (SAE) at 6800 rpm and at 273 lb.-ft. of torque at 4,250 rpm. A dual-stage resonance air intake system helps the engine provide 214 lb.-ft. of torque at as few as 2,000 rpm and at least 236 lb.-ft. from 2,500 to 7,000 rpm, with a mid-range torque “plateau” of at least 265 lb.-ft from 3,800 to 6,000 rpm.

Combined with the inherent light weight yet high strength of the 911 Carrera Cabriolet sports car architecture, the 3,267-pound Carrera 4 Cabriolet can accelerate from a standing start to 62 mph (100 km/h) in only 5.2 seconds when equipped with the standard six-speed manual transmission. Acceleration times are marginally slower for cars equipped with Porsche’s optional Tiptronic® S five-speed automatic transmission.

The 911 Carrera 4 Cabriolet can achieve a top test track speed of 177 mph (285 km/h), yet when run through the six-speed manual transmission, its fuel-efficient engine is rated at 18 mpg city (13.3 liters/100 miles) and 26 mpg highway (8.3 l/100km). Fuel economy figures are marginally decreased when the Cabriolet is equipped with the five-speed Tiptronic S automatic transmission.

Porsche owners know that such speed is only part of the equation. The 2004 Porsche 911 Carrera 4 Cabriolet achieves optimum balance between performance and handling, between exciting dynamics and luxury amenities, and between active and passive safety technologies.

After the Porsche 911 Carrera models underwent significant changes for the 2002 model year, the only other alternations for the 2004 model year launch are two new colors: Atlas Gray metallic and Carmon Red metallic.

The Porsche 911 Carrera 4 Cabriolet offers 2+2 seating and Porsche’s classic rear-engine vehicle architecture, which Professor Ferdinand Porsche championed when he created the original Volkswagen. Dr. Ferdinand “Ferry” Porsche, Professor Porsche’s son, improved this basic platform when he created the 356, which was powered by an air-cooled four-cylinder engine. The revolutionary car was the foundation for the Porsche sports car company we know today.

The 1964 Porsche 911 Carrera introduced the company’s first six-cylinder “boxer” engine, a 2–liter unit that produced 148 horsepower and 129 lb.-ft. of torque.

In 1999, Porsche introduced its newest family of six-cylinder, horizontally opposed “boxer” engines. Since then, the engines used in the 911 Carrera models have been equipped with a new crankshaft, pistons and connecting rods, and displacement has been increased to 3.6 liters. Porsche’s patented VarioCam® Plus intake valve timing and lift system further enhance its output. Patented LOKASIL high-silicon cylinder liners help reduce friction and wear to such a level that Porsche can recommend a 15,000-mile (24,000 km) oil change interval and a 30,000-mile (48,000 km) oil filter change interval.

The latest version of VarioCam Plus adjusts camshaft position to provide continuously adjustable intake valve timing and also incorporates two camshaft profiles and two sets of tappets to vary both intake valve lift and duration. This system helps “flatten” and smooth out the torque curve, while helping to reduce emissions.

Motronic ME 7.8 engine management controls instantly calculate the precise supply of fuel needed from the tank. Formerly, fuel not needed by the injectors – but heated by the engine – went back to the fuel tank. This “returnless” system reduces hydrocarbon emissions caused by prematurely heated fuel. Further, sequential multi-port fuel injection features separate fuel mixture control for each cylinder bank, and a coil-on-plug ignition system provides quick response and reliable operation.

The ME 7.8 engine control module incorporates the E-Gas electronic throttle. In place of a traditional throttle cable setup, E-Gas electronically transmits pedal position to the engine control unit.

Low backpressure mufflers emit a powerful sound through the Porsche 911 Carrera’s tailpipes.

Porsche offers a choice of two transmissions for the 911 Carrera models: a precisely shifting standard six-speed manual and the optional Tiptronic S five-speed automatic transmission.

The manual has high-strength steel alloy components that can accept the the 911 Carrera engine’s power. The gearbox’s output shaft runs on three bearings, not two as is the practice of many automakers, and the differential has strengthened bevel gears. A dual-mass flywheel ensures low vibration, and a hydraulic clutch provides consistent performance.

The 911 Carrera models adopt the Tiptronic S transmission from the 911 Turbo. The lock-up torque converter and shifting programs have been specially tailored to the naturally aspirated engine.

In automatic mode, Tiptronic S uses infinitely variable shift points to respond to driving circumstances and driving style. During leisurely driving, Tiptronic S upshifts early to provide a quiet ride and the best fuel efficiency. With quicker manipulation of the gas pedal, the transmission responds by raising shift points to hold each gear longer for crisp response and power.

The Tiptronic S transmission draws from among 250 different shift maps to provide optimal performance at all times. Even 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 allows the driver to select manual mode by pressing an up- or downshift button, even with the shift lever in the “D” position.

The four-wheel independent suspension under the 911 Carrera 4 Cabriolet features a Porsche-optimized MacPherson-strut design in front and a multilink setup in the rear, each using aluminum 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 neutral handling in the 911 Carrera models. Carrera II 17-inch wheels use a slender spoke design to reduce unsprung weight by more than 5 pounds per wheel over the previous design.

The standard aluminum alloy wheels measure 7 x 17 inches in front and mount 205/50 ZR17 tires; the 9 x 17-inch rear wheels mount 255/40 ZR17 tires. The optional 18-inch wheel/tire package further enhances the already sharp handling. The wheels measure 8 x 18 inches in front and 10 x 18 inches in back; tires are 225/40 ZR18 in front and 285/30 ZR18 in back.

The 911 Carrera 4 Cabriolet 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 heat and unsprung weight. The front discs measure 12.5 inches in diameter and 1.1-inches thick (318 mm x 28 mm). The rear discs measure nearly as large at 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 requires brakes to provide 25 consecutive full-force stops without fade.)

A high level of occupant protection comes with the high performance potential of all 911 Carrera models. A patented crumple zone body structure protects a reinforced passenger compartment. Supplementing the three-point inertia-reel seatbelts, the 911 Carrera models have seatbelt pretensioners and load limiters. 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 side bags provide additional protection for the chest, head, and pelvis.

The 911 Carrera 4 Cabriolet has boron-steel reinforced A-pillars and windshield header and an automatic-deploying supplemental rollover structure to reduce the risk of injury in the event of a rollover accident.

At a customer’s request, an authorized U.S. Porsche dealer can install a system that deactivates the passenger airbags when a U.S. Porsche-approved child seat is used. The system features a cross brace with belt lock in front of the passenger seat. Buckling the special child seat into this brace deactivates the airbags. To install the system, the dealer also must reprogram the airbag control module.

The Porsche 911 Carrera 4 Cabriolet has a beautiful but strong body structure designed to enhance ride, handling and safety. The latest styling update adopted the 911 Turbo’s headlight design, reshaped the front end, widened rear quarter panels and redesigned the tail pipes.

But at Porsche, design involves both form and function. The revised front air intakes increase airflow to the radiators by 15 percent. Reshaping the radii of the front wheel arches and the addition of small, flexible spoilers ahead of the front wheels reduce lift at the front by 25 percent and at the rear by 40 percent. The revised air intake ducts enhance front brake cooling, and an under-floor duct enhance transmission cooling by 20 percent.

Even the headlight design improved lighting performance. The Bi-Xenon gas-discharge headlights that are standard on the 911 Turbo are an option for the 911 Carrera 4 Cabriolet. These light units use high-intensity gas discharge bulbs for both the low and high beams.

Optional parking aid with sensors integrated into the front and rear bumper covers can help prevent parking maneuver fender-benders by sounding an audible alert as the car gets closer to an obstacle.

Porsche’s Communication Management system (PCM®) is an option that comprises tuners, CD player, navigation system, and trip computer, all linked through Media-Oriented Systems Transport (MOST) digital databus. The MOST system incorporates light-wave conductors that exchange data between the individual components without loss of quality and at ultra-high speeds.

PCM includes a 5.8-inch (147 mm) screen with its 16:9 aspect ratio and 12-position keyboard for easily and efficiently entering radio frequencies. The system assures excellent audio quality. The navigation module provides such features as road junction zoom-in, dynamic navigation to avoid congestion, map scrolling so you can see beyond your current position, tour planning with the ability to memorize as many as eight destinations in a row and a CD-ROM system that can be used for the navigation system or for music.

The instrument panel of all 2004 Porsche 911 Carrera models include a standard onboard computer that conveys information on an LCD display in the lower third of the tachometer. In addition to information about fuel consumption and driving range, the computer can display engine oil level, outside temperature and 35 different warning messages in plain text.

A three-spoke sports steering wheel is standard. The remote entry system controls seat memory function when the optional power seats are ordered. The remote determines which of the four car keys is in use and transmits the information for driver’s seat position and exterior mirrors to the memory control unit. Apart from the function provided by the four programmable keys, the driver can select two other seat positions via buttons to the left of the seat.

The 911 has a lockable glove box and a cup holder integrated into the center of the dashboard.

Porsche offers a high-end digital audio system from home and automotive audio manufacturer Bose. Each system has been custom-engineered for that particular model. The Bose automotive music systems combine balanced stereo, a panoramic sound stage, deep bass and smooth frequency response to produce lifelike music reproduction even in the challenging environment of a car interior. Digital amplifiers provide clean, uncolored sound at any listening level. The 11 advanced loudspeakers and a subwoofer blend seamlessly into cabin trim, raising and widening the sound stage and ensuring balanced stereo.

All Porsche models feature light-emitting diode (LED) interior orientation lights. One LED provides gentle illumination of the cockpit and center console. An LED on the driver’s side door handle illuminates the ignition lock and light switch, and an LED illuminates each door latch.

Porsche Cars North America offers customers in the United States and Canada the opportunity to personalize their cars through two option-selection channels. Together with the choice of limited-availability special paint colors, the special options allow a customer to make a Porsche into a truly one-of-a-kind car. The Porsche Exclusive program offers a wide array of optional features installed at the factory. Options include custom interior trim packages and individual trim items.

The Porsche four-year/50,000 mile bumper-to-bumper warranty covers all Exclusive options, and Porsche dealers can include the cost of the options in the lease or finance contract.

The Tequipment (“Tech-quipment”) program offers a line of accessories available only from authorized Porsche dealers. Tequipment options include such items as special wheels, an aerobody kit, instrument panel trim kits, CD changers, and custom floor mats. Customers can order Tequipment options at the time of purchase or return to the dealership for installation later. While installation of Tequipment may require some modifications to the car, such modifications do not affect the standard limited warranty. Tequipment items come with a two-year warranty when installed by a certified technician at an authorized Porsche dealership.

In addition to the limited-availability special paint colors, Porsche will paint a 911 Carrera to match a sample from the customer. The Porsche 26-step corrosion protection and paint process ensures that the custom paintwork meets the same quality standards as a regular production paint color. The Porsche three-year/ unlimited mileage paint finish and 10-year/unlimited mileage corrosion perforation warranties apply to any custom color.

Story by Porsche Edited by Maximum-Cars.com