2004 Porsche 911 Turbo Coupe

But for 911 Turbo Coupe drivers who want even more power under their control, an optional factory-installed X50 engine enhancement performance package boosts the turbochargers’ pressure to generate 444 horsepower (SAE) and 457 lb.-ft. of torque.

Porsche began using turbochargers in the famed Porsche 917 racecar in the early 1970s and introduced its first 911 Turbo production model in 1974. The 911 Turbo arrived in the United States for model-year 1976, and with its 234-horsepower (SAE) engine could achieve 0-62 miles per hour (0-100 km/h) in 5.5 seconds.

Porsche also pioneered innovations that increased turbocharging reliability, including the exhaust wastegate to regulate boost pressure and intercoolers to reduce the temperature of the compressed intake air.

Porsche pioneered the all-wheel drive supercar with the limited production 959 of the mid-1980s. Although not imported to North America, the turbocharged 959 became a Porsche legend and paved the way for the first standard-production all-wheel drive Porsche 911 Turbo, which arrived in the United States for 1996.

From the beginning, Porsche designed the 911 Turbo as a fully equipped grand touring car with a high level of standard luxury features. For 2004, the Porsche 911 Turbo is offered in two new colors – Atlas Gray metallic and Carmon Red metallic. It also comes with a special new Turbo tachometer and with two new options: 18-inch SportTechno wheels and 18-inch GT3 wheels.

A racecar-derived 3.6-liter, twin-turbo six-cylinder engine gives the 911 Turbo staggering performance capabilities. The engine produces 415 horsepower (SAE) @ 6,000 rpm and sustains 415 lb.-ft. of peak torque from 2,700 to 4,600 rpm. Power drives through a standard six-speed manual transmission, with the advanced Tiptronic® S five-speed automatic transmission as an option.

With power characteristics of a far larger engine, the 911 Turbo Coupe can accelerate from 0 to 62 mph (0 to 100 km/h) in just 4.2 seconds. On the test track, the 911 Turbo sprints from a standstill to 99 mph (160 km/h) in only 9.3 seconds and can achieve a top track speed of 189 mph (305 km/h).

The 911 Turbo engine is based directly on the 3.6-liter engine from the GT1 racecar that won the 24 Hours of Le Mans in 1998. (The engine is not a turbocharged version of the 3.6-liter unit used in the 2004 911 Carrera models.) To accommodate the high boost pressure produced by its dual turbochargers, the engine features a 9.4-to-1-compression ratio, compared to 11.3-to-1 for the 911 Carrera models. Intake air enters through louvers in the engine lid, flows into a joint air filter housing
and then into the turbochargers. The turbos compress the air to a maximum of 11.76 psi (0.8 bar over atmosphere). From the turbos, the intake air flows through dual intercoolers (one mounted in each rear fender) and then into the induction system.

Like all current Porsche engines, the 911 Turbo features double overhead camshafts and four valves per cylinder. The new-generation 911 Turbo introduced a new version of the Porsche VarioCam® valve timing system. Called VarioCam Plus, the new system provides continuously adjustable intake valve timing. The system helps boost low-end and mid-range torque. Dual valve springs ensure reliable,
high-performance operation.  Sequential multi-port fuel injection features separate fuel mixture control for each cylinder bank, and a coil-on-plug (“distributorless”) 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 conventional throttle cable setup, E-Gas electronically transmits pedal position to the engine control unit. The new system provides even sharper throttle response and ensures low emissions.

The 911 Turbo also offers an optional X50 engine enhancement performance package that increases horsepower to 444 (SAE) @ 5,700 rpm and sustains 457 lb.-ft of peak torque from 3,500 to 4,500 rpm. The new package includes modifications to the turbocharger, air intake cooler, electronic control unit,
exhaust system, as well as a strengthened transmission. The X50 package is only available as an option from the Porsche factory.

The 911 Turbo offers a choice between a precise-shifting standard six-speed manual transmission 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”, or Drive, and let the transmission do the shifting, or shift into “M”, Manual, and control gearshifts with steering wheel-mounted thumb switches. In automatic mode, Tiptronic S uses infinitely variable shift points to respond to the driving circumstances and the driving style. During leisurely driving, Tiptronic S up shifts early to provide a quiet ride and the best fuel efficiency. With quicker gas pedal action, 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. 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 allows the driver to select manual mode by pressing an up- or downshift button, even with the shift lever in the “D” position.

The 911 Turbo 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 Turbo qualifies as one of the lightest such systems in the industry.

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 911 Turbo exhibits outstanding traction on all road surfaces. However, Porsche did not originally intend the all-wheel drive system as an all-weather traction assistant.