1976 Turbo Carrera (930)
1994 Turbo 3.6 (964)
1996 Turbo (993)
2001 Turbo (996)
2007 Turbo (997)
1975–89 930: The First Turbo 1976 Turbo Carrera (930) ” />
The 930, or simply “Turbo,” was introduced as a 1975 model at the Paris Auto Show. It would arrive in the U.S. for the 1976 model year as the Turbo Carrera, priced at $26,700. Since the next most expensive Porsche was the 911S Targa at $16,160, Stuttgart was concerned about its ability to sell such an expensive production car. Its plan: Build only the 400 required for homologation over a two-year period. It needn’t have worried. More than 23,341 first-generation Turbos were built between 1974 and the end of 1989 MY production.
The Turbo moved from a die-cast magnesium crankcase to a far stronger die-cast aluminum crankcase. A bore of 95 mm and a 70.4-mm stroke resulted in 3.0 liters of displacement. Running 0.8 bar (11.6 pounds) of boost, it made 260 DIN horsepower. A larger, four-speed 930 transmission coped with the added power, but the brakes weren’t so lucky. Standard 911S gear would have to do, and it barely did. With the more powerful engine came fender flares, a “whale tail,” a small front lip, and 15×7 and 15×8 wheels. Suspension tuning and geometry was modified, with 19-mm front and 26-mm rear torsion bars and specially cast rear trailing arms. The standard tires were 185/70VR15s front and 215/60VR15s rear, with 205/50VR15s and 225/50VR15s available as an option.
1976’s U.S. Turbo made 245 hp thanks to a thermal-reactor exhaust system meant to meet U.S. emissions laws. The 205/50VR15 and 225/50VR15 tires became standard equipment that year, as well. 1977 added power-assisted brakes for the first time. It was also the first model year to have a boost gauge in the tachometer. The rear suspension spring plates were now two-piece units and had eccentric adjustment to permit the two pieces to be adjusted in relationship to each other. This was done to permit fine-tuning of the suspension to better balance the rear weight on the rear wheels. 930s received the new, simpler front anti-roll bar that had been used on 911s since 1974. The anti-roll bars measured 20 mm front and 18 mm rear. The tires and wheels were upgraded to 205/55VR16s on 16×7s up front and 225/50VR16s on 16×8 rears. The heater was controlled by a thermostatic control valve while heated, electrically adjustable side mirrors were made standard.
For 1978, a bore increase to 97 mm and a longer stroke of 74.4 mm yielded 3.3 liters. More importantly, the Turbo became the first production car to utilize an intercooler. Thanks to the intercooler, a higher compression ratio could be used. Static compression was increased from 6.5:1 to 7.0:1, resulting in a theoretical overall effective compression ratio as high as 11.7:1. European models made 300 DIN hp, while U.S. versions moved from the original 245 hp to 265 hp at 0.8 bar. The reduction of power from the Euro version was again a result of U.S. emissions devices and the thermal-reactor exhaust system.
1978 Turbos wore a new tail, one that was both more efficient ärodynamically and provided space and increased airflow for the engine-mounted intercooler. Larger brakes with ventilated and cross-drilled brake rotors were used on 1978 Turbos, clamped by calipers that were a production development of the four-piston units used on the Can-Am 917. The 1979 model was essentially the same car, and was the last Turbo brought into the U.S. in real numbers until 1986. Just 80 1980 models (built before 1980) snuck in. Porsche continüd to develop the Turbo from 1980 through 1985, and a number of European Turbos were brought into the U.S. as gray-market cars.
The 1980 Turbos got a new muffler with twin outlets instead of the original single outlet. The change was supposed to quiet the noise from 82 dBA to 79 dBA without any loss of power. Porsche also replaced the serpentine front oil cooler with a brass-tube cooler. 1981’s Turbo was unchanged, but the 1982 cars got an oil trap on the crankcase vent line to prevent throwing oil out of the oil tank through the vent into the engine air filter during aggressive driving. To improve interior heat, two extra heater blowers were added for 1983. The exhaust system was revised and a separate muffler was added for the wastegate. Previously, the wastegate also dumped into the primary muffler. This change increased the European Turbo’s maximum torqü from 304 to 318 lb-ft. The CIS fül injection was also revised with a different warm-up regulator and fül distributor. There were no changes for 1984, but 1985 models got a new finned front oil cooler. To provide extra airflow, the opening in the front bumper was enlarged.
For 1986, the 930 was reintroduced to the U.S., but this time as the “911 Turbo.” A new catalytic converter-equipped exhaust system with an oxygen sensor met U.S. requirements while allowing the car to make 282 hp. 1986 also brought new rear wheels and tires. The rim size was changed from 16×8 with a 10.3-mm offset with 225/50VR16 tires to 16×9 with a 15-mm offset with 245/45VR16 tires. For 1987, Targa and Cabriolet versions were available for the first time. The 1988 Turbo was essentially the same, but 1989 brought a key upgrade: the G-50/50 (950) five-speed manual transmission. Essentially a stronger version of the G-50 transmission used in the Carrera since 1987, it had uniqü gear ratios to improve the Turbo’s acceleration and driveability. Five rather than four speeds didn’t hurt, either. With the G-50/50 came hydraulic clutch actuation as well as tweaks to the torsion bar tube (to make space for the larger gearbox) and the rear suspension tuning.
From 1987 to 1989, Porsche also built 948 911 Turbo “Slant Nose” models (also known as “Slope Nose” and 930S).?The cars were instantly recognizable for their lack of traditional 911 headlight humps, substituting flat (or sloped) front fenders with pop-up headlights instead. They also added boxed rockers and rear fender vents. These upgrades were cosmetic-only, but the option added roughly $30,000 to the bottom line. Even so, 630 were imported to the United States: 200 cars for 1987, 283 for 1988 and 147 cars for 1989.
1991–94 964: The Second Generation
After a year’s absence, the 911 Turbo was back for 1991. It still had the 930’s fat fender flares, but it adapted them to the 964’s smoother, polyurethane-reinforced front bumper and lower side panels of the same flexible material as well as a new thermoplastic rear bumper. Its tail looked like the one used on 1978–89 models, but was larger. 1991’s Turbo also introduced new ärodynamic side mirrors similar to the 959’s. The running gear was based on what Porsche used in the 1990 964 Carrera 2, incorporating the 964’s Bosch hydraulic brake booster and anti-lock braking system as well as its power steering.
The engine was essentially an update of the previous Turbo 3.3, with a K27.2 Turbo and an intercooler that had approximately 50 percent more surface area. It was still equipped with the old CIS fül-injection system, but the ignition system was electronically mapped like the ignition portion of the Motronic system used in normally-aspirated Carrera 2/4s. The changes improved the performance of the old 3.3, increasing its output to 315 hp for the U.S. version and 320 hp for the European version.
The 1991 model was the first Turbo to be equipped with airbags, and had airbags for both the driver and the front-seat passenger. Boost pressure was monitored by a digital display at the bottom of the tachometer. From 1991, all Porsches were fitted with a new alarm system with central locking, interior light delay control, and an anti-drive-off feature. The new alarm had a diagnosable, microprocessor-controlled system.
Like the C2 and C4, 1991’s Turbo used a dual-mass flywheel. The ZF limited-slip differential was changed to an asymmetrical design with a lock-up factor of 20 percent under load and 100 percent under braking, the latter to stabilize handling by reducing trailing throttle yaw and its resulting oversteer effects. Porsche found that 20 percent lock-up under load was high enough to provide adequate traction without disrupting the handling and causing understeer. The 1991 Turbo’s 17×7 front wheels wore 205/55ZR17s while its 17×9 rears were shod with 255/40ZR17s.
For 1992, the power steering was fitted with rotary-valve steering in place of the sliding-vane pump used in 1991. In addition to the regular Turbo, Porsche offered 20 Turbo S2 models in the U.S. as a homologation basis for IMSA’s?Supercar series. The S2’s 3.3-liter engine had more radical cams, a larger intercooler, and a different turbo with a larger compressor. All that added up to a modest power bump according to Porsche: 322 hp and 354 lb-ft, up just 7 hp and 22 lb-ft.
Porsche introduced the Turbo 3.6 and sold it in the U.S in 1993 and 1994 as a 1994 model. Its 3.6-liter flat six was based on a normally-aspirated 964 engine modified to (still…) use CIS fül injection. Power moved up to 360 hp. Modular Speedline wheels were used, 18×8s up front and 18×10s in the rear, shod with 225/40ZR18s and 265/35ZR18s. The Turbo 3.6 was also the first Porsche to use “big red” Brembo brake calipers. At the end of Turbo 3.6 production, Porsche built a special series of 86 Turbo S models. These cars had 385 hp and a new take on the Slant Nose concept, with exposed lay-down 928-style headlights. 49 were built for the U.S. market, but not all of them had the Slant Nose bodywork.
1995–98 993: The All-Wheel-Drive Turbo
The 1996 Turbo debuted in March of 1995 at the Geneva Auto Show. Based on the 993 Carrera 4, it was the first Turbo to use all-wheel-drive. It was also the first to feature twin-turbocharging, another feature recalling the 959 supercar. At long last, the Turbo also got Motronic engine management, the first major advancement in Turbo technology since the 1978 model’s intercooler. Performance and throttle response were greatly improved dü to the new engine management and the twin turbos.
With AWD, six speeds, and 408 twin-turbocharged horses, Porsche called this Turbo its supercar for everyday use. Its brakes had almost 2,000 hp of stopping power — and had to be experienced to be believed. New hollow-spoke wheels had wheel centers and outer rims that were inertia-welded together. They measured 18×8 and 18×10 and wore 225/40 and 285/30 tires. To the 993’s popular bodywork, the Turbo added a new rear spoiler, a revised front bumper, and 25-mm wider rear fenders.
1997 Turbos got stronger transmission input shafts, increased in size to cope with the car’s immense power and all-wheel-drive traction. 1997 models also had modifiable ECU units that could be flash modified, while the standard wheel center caps said “Turbo.” (Standard 1996 caps had a Porsche crest.) In 1997, Porsche offered a Turbo S with 424 hp in the U.S. and 450 hp for RoW cars. It had yellow brake calipers, a slightly larger rear wing, four exhaust pipes, carbon-fiber interior trim, and air scoops on the rear flares. Though 1998 would mark the end of the air-cooled 911 Turbo, 1997 was its U.S. swan song.
2001–present: The Water-Cooled Turbos
When the 2001 Turbo finally bowed, it shared the basic architecture but very little else with the all-wheel-drive 996 Carrera 4. One example was the engine, which was completely different to the 996’s. It was an evolution of the flat six in the Le Mans-winning 1998 911 GT1. The engine was developed as a continuing evolution of the original 1964 911 flat six but was no longer air-cooled. While its crankcase and drop-forged, eight-main-bearing crankshaft were similar to those in air-cooled 911 engines, the 996 Turbo used two cylinder heads instead of six, one for each bank of three water-cooled cylinders. The heads were made of a highly heat-resistant aluminum alloy.
For the first time, the Turbo got dual overhead cams, guided and tensioned by ramps and hydraulic tensioners similar in design to those used in 959s, 964s, and 993s. The intake cams featured VarioCam Plus, which controlled lift and timing via hydraulic pressure. The Motronic 7.8 engine management determined when these changes happened depending on a variety of inputs, including throttle position, load, temperatures, gear selection, and more. The result of all this, plus twin intercoolers mounted in the rear fenders, was 415 horsepower.
The 2001 Turbo was the first to be offered with an automatic transmission — a five-speed Tiptronic with two reverse gears and 250 shift maps. A six-speed manual was standard. Huge wheels and tires (18×8s with 225/40s up front and 18×11s with 295/30s in the rear) fit under bodywork that was 2.6 inches wider in the rear than a standard 996. Huge front-bumper openings fed three radiators with 50 percent more surface area than a standard 996’s radiators. The leading edge of the rear fenders had functional inlets for the intercoolers, which dumped into 959-ish vents in the rear bumper. Porsche’s PSM electronic stability management system was standard.
For 2002, the Turbo got effective cup holders as well as a lockable glovebox. Also new were optional Porsche Ceramic Composite Brakes. A number of changes were made in the sill, roof frame, seat pans, and tunnel to improve the flexural and torsional strength by 25 percent. The B-pillar was also modified to accept new seatbelt tensioners and force limiters. Finally, an X50 Powerkit was made available, with 450 hp and 457 lb-ft of torqü. The package included different turbos, intercoolers, engine management tuning, a revised exhaust system, and a strengthened transmission. No new features or changes were made for 2004, but Porsche put a Turbo Cabriolet into production for the first time since 1989. For 2005, a Turbo S coupe and Cabriolet were added, with 444 hp and 457 lb-ft torqü, standard PCCBs, a slightly darker GT Silver finish on the wheels, and aluminum gauge faces. Most Turbo were Cabriolets.
After a one-year break in production, the Turbo was back for 2007, this time based on the 997. One of the most obvious changes was a return to “round” headlights like those used before the 996. Once again, the Turbo had wider bodywork than the C4 it was based on and different bumpers. The retractable rear wing concept was carried over from the 996 Turbo, as well.
The engine was Porsche’s first to use variable-geometry turbochargers. Power was up to 480 hp and 460 lb-ft of torqü. An overboost function — in conjunction with the optional Sport Chrono Package — increased boost by approximately 2.9 psi, thereby increasing torqü to 502 lb-ft for up to ten seconds. Pressing SCP’s “Sport” button?also stiffened the 997 Turbo’s electronically adjustable PASM dampers while relaxing its more advanced PSM?system. The new engine had further advancements in the VarioCam Plus system and the oiling system, the latter featuring one more oil pump (for a total of nine) to cope with the high braking forces of the 997 Turbo.
GT2: The Driver’s Turbo
For 2002, Porsche introduced the GT2, a high-performance, rear-wheel-drive version of the Turbo. Power was increased to 462 hp and 457 lb-ft of torqü thanks to larger turbochargers, more boost, an improved exhaust system, and more efficient intercoolers with more surface area. The GT2’s distinctive front bumper featured larger inlets for more flow to the radiators as well as a topside outlet in front of the hood to evacuate the center radiator and reduce front-end lift at speed. The rear engine lid had a fixed but adjustable rear spoiler. Engine air was ducted through the ends of the rear spoiler into an integrated airbox in the engine compartment lid.
The six-speed manual transmission from the 911 GT3 was used as the basic transmission for the GT2, which meant the GT2 got a dual-mass flywheel, a cable-shift mechanism; a transmission oil cooler, and an oil pump for internal spray bar lubrication. An asymmetrical limited-slip differential set to 40 percent lock-up on acceleration and 60 percent for deceleration was used, and the transmission was equipped with steel synchronizer rings for third, fourth, fifth, and sixth gears.
The chassis was set up for serious driving. Porsche started with GT3 parts and modified them to achieve specific requirements considering the car’s weight and performance. Unlike the Turbo, the GT2 didn’t have PSM’s electronic safety net. Its wheels measured 18×8.5 front and 18×12 rear, and wore 235/40ZR18 and 315/30ZR18 tires. The GT2 had no spare tire, instead using what Porsche called a “Tire Mobility System,” which consisted of a bottle of sealant, a compressor, and a tire-pressure tester. (Beginning with MY?2005, no U.S. Porsches carried spare tires — so be sure to have a cell phone handy!)
The 911 GT2 was the first Porsche to come with the PCCB?ceramic-composite brakes as standard equipment. The major advantages of these was a 50-percent reduction in rotating unsprung mass (36 pounds lighter than the Turbo’s brakes), fast response, maximum fading stability because of constant cöfficient of friction, excellent response in the wet, and long service life. Up to 185,000 miles was projected — initially. The proven, single-piece aluminum brake caliper was also used, but the GT2’s front calipers had six pistons (the rears still had four). ABS 5.3 was adapted from the GT3’s three-channel ABS system with control parameters specific to the GT2.
There were only minor changes to the GT2 for 2003. For 2004, the engine for the GT2 was further developed to produce 483 hp and 472 lb-ft. New 10-spoke wheels were made standard while the suspension benefitted from tuning refinements. A new carbon-fiber exterior appearance package was offered.
What to Buy
All of these Porsches offered extraordinary performance in their day —?performance that still holds up in many cases. The earlier Turbos do suffer from excessive turbo lag, so if you can’t deal with lag you’re best off to start out at 1996’s 993 Turbo, with its twin turbochargers and superior Motronic engine management. Perhaps the best valü of the bunch is the 996 Turbo, which has fallen out of favor ästhetically but remains a technical tour de force. One word of caution with 996s and 997s, however: If they’re equipped with PCCBs, be sure the brakes are in good shape. The alternative is a five-figure replacement bill.
Because Turbos are more complex, anticipate higher repair and maintenance costs than those of a standard 911. Insurance will likely be more expensive, too. As always, have a reputable shop check out any car you are serious about buying. This relatively small investment can steer you away from cars that would cost thousands of dollars to restore to serviceable condition. Make sure the shop carefully inspects the car for accident damage, neglect, or cost-cutting maintenance habits.