Porsche 944
The Porsche 944 is a sports car which was manufactured by the German company Porsche from 1982 until 1991. A front-engine, rear-wheel drive model based on the platform of the 924, the 944 was available in coupé or cabriolet body styles, with either naturally aspirated or turbocharged engines. With over 163,000 cars produced, the 944 was the most successful sports car in Porsche's history until the introductions of the Boxster and 997 Carrera.
Extensive design revisions for the 1992 model year prompted Porsche to drop the 944 nameplate and rebrand the vehicle as the 968.
History
The 924 had originally been a project of VW-Porsche, a joint Porsche/Volkswagen company incorporated to develop and produce the 914 which was sold in Europe badged as both a Porsche and a Volkswagen. In 1972, a replacement for the Volkswagen version of the 914, code named EA-425 began development. The model was to be sold as an Audi as part of the VW-Audi-Porsche marketing arrangement. Porsche was to manufacture its own version of the car. At one point, Volkswagen head Rudolf Leidig declared the EX-425 was going to be a Volkswagen exclusively, thus denying Porsche's version of the 914's replacement. Although testing had begun in the spring of 1974, Volkswagen cancelled the EX-425 program, the reason being significant financial losses due to declining sales and rising development costs for new vehicles as well as the departure of Leidig. The recently introduced Volkswagen Scirocco was expected to fill the sports coupé market segment and the unfinished project was handed over to Audi to serve as the replacement for the Audi 100.The cancellation of the EX-425 program led Porsche to market an entry-level car to replace the 912E, which was a US-only stop-gap model for 1976, and their version of the 914, which was discontinued in 1975. Porsche purchased the design and the finished development mule with a Bosch K-Jetronic mechanical fuel injection system from Volkswagen. The vehicle, dubbed the 924, received positive reviews, but was criticised by Porsche enthusiasts for its Audi-sourced 2.0 L engine. In 1979, Porsche introduced a Turbocharged version of the 924 to increase performance, but this model carried a high price. Rather than scrapping the model from its line-up, Porsche decided to develop the 944, as they had done with generations of the 911; although model numbers would change, the 924 would provide the basis for this new mid level model.
The prototype of this mid level model debuted at LeMans in 1981, an unusual strategy implemented by Porsche at the time. Called the 924 GTP LeMans, the car was based on the 924 Carrera GT LeMans that competed in the event prior to the GTP's introduction. The most noticeable change in the new race car was the departure from the Audi sourced 2.0 L inline-4 engine in favour of the 2.5 L engine developed by Porsche. The new engine was mounted at an angle of 45 degree to the right and utilised a dual overhead camshaft along with counter rotating balance shafts, an unusual feature for its time that provided better weight distribution and ensured smooth power delivery by eliminating inherent vibrations resulting in the engine lasting longer. A single KKK turbocharger producing enabled the engine to generate a maximum power output of at 6,800 rpm. The engine also utilised Bosch's prototype Motronic engine management system to control ignition timing, fuel injection and boost pressure. The new race car proved to be much more fuel efficient than its predecessor, stopping only 21 times in 24 hours for fuel. The 924 GTP managed seventh position overall behind the race winning 936 and a class win at the GTP+ 3.0 category in 1981 before being retired and stored in the Porsche museum. In 1982, Porsche debuted the production road legal version of the race car, called the 944. The car utilised many technologies its race bred sibling had used, including the balance shafts and the engine management system, but power was toned down for safety purposes.
The new all-alloy inline-four engine, with a bore of and stroke of, was in essence, half of the later 928's 5.0 L V8 engine, although very few parts were actually interchangeable. Not typical in luxury sports cars, the four-cylinder engine was chosen for fuel efficiency and size, because it had to be fitted from below on the Neckarsulm production line. To overcome roughness caused by the unbalanced secondary forces that are typical of inline four-cylinder engines, Porsche included two counter-rotating balance shafts running at twice the engine speed. Invented in 1904 by British engineer Frederick Lanchester, and further developed and patented in 1975 by Mitsubishi Motors, balance shafts carry eccentric weights which produce inertial forces that balance out the unbalanced secondary forces, making a four-cylinder engine feel as smooth as a six-cylinder engine. Porsche spent some time trying to develop their own system, but when they realised that they could not improve on the system developed by Mitsubishi, they chose to pay the licensing fees rather than come up with a variation just different enough to circumvent the patent. The licensing fees were about US$7–8 per car, which translated to about US$100 for the consumer to pay. The engine was factory-rated at in its U.S. configuration. Revised bodywork with wider wheel arches, similar to that of the 924 Carrera GT, a fresh interior and upgrades to the braking and suspension systems rounded out the major changes.
Models
944
Porsche introduced the 944 for the 1982 model year. It was slightly faster, was better equipped and more refined than the 924; it had better handling and stopping power, and was more comfortable to drive. The factory claimed a 0-97 km/h acceleration time of less than 9 seconds. The car had a nearly even front to rear weight distribution courtesy of the rear transaxle balancing out the engine in the front. North American-market cars had bigger bumpers and the front bumper had a larger rubber portion, replacing the auxiliary lights as required by the North American laws.In mid-1985, the 944 underwent its first significant changes, these included: new dashboard and door panels, embedded radio antenna, upgraded alternator, increased oil sump capacity, new front and rear cast alloy control arms and semi-trailing arms, larger fuel tank, optional heated and powered seats, Porsche HiFi sound system, and revisions in the mounting of the transaxle to reduce noise and vibration. The front windshield was now a flush-mounted unit. The "cookie cutter" style wheels used in the early 944s were upgraded to new "phone dial" style wheels.
For the 1987 model year, the 944 Motronic DME was updated, and an anti-lock braking system and driver and front passenger airbags were introduced. The 944 Turbo was the first car to offer airbags as standard equipment; they were optional on other 944 models. Because of the ABS, the wheel offset was changed to, and Fuchs wheels were no longer available as an option.
In early 1989 before the release of the 944S2, Porsche upgraded the 944's engine from the 2.5 L four cylinder engine to a 2.7 L engine having a bore of and stroke of, with a rated power output of and a significant increase in torque. In addition to the increase in displacement, the new engine featured a siamesed-cylinder block design and a different cylinder head which incorporated larger valves.
Callaway 944
In 1983, American tuning company Callaway Cars began offering a turbocharged package for the US-Spec 944 in collaboration with Porsche. The standard 2.5 L straight-four engine was not suitable for forced induction because of the higher compression ratio of 9.5:1 which made the engine prone to failure when subject to forced induction along with the complex Bosch Motronic engine management system. Callaway engineers overcame this problem by increasing the volume of the engine's combustion chambers by milling away metal from both piston heads and chamber walls and by tweaking the Motronic system so it would ensure optimum fuel injection to the turbocharged engine along with installing their own Microfueler unit. This step was highly effective, but required disassembly of the entire engine, leading to the high cost of the package. The resulting engine's compression ratio was of 8.0:1 which was less than the standard engine but ensured linear power delivery. In order to ensure that there were no serious engine breakdowns, Callaway installed an ubiquitous internal waste gate recommending the use of 91-octane fuel in order for increased engine reliability. In addition to that, an IHI RHB6 turbocharger was installed on the right hand side of the engine along with a new free flow exhaust system incorporating a larger exhaust pipe for optimum performance. The small turbocharger eliminated turbo-lag thus ensuring linear levels of boost. The turbocharger produced 10 psi of boost, however a boost adjuster knob located on the dashboard was optional. With these modifications, the engine generated a power output of at 6,000 rpm and at 4,000 rpm as opposed of the standard car's at 5,500 rpm. Performance increased over the standard car as well, with a acceleration time of 5.9 seconds and a top speed of. Callaway quoted that the acceleration times would even be lower if the rev limiter was removed. Only 20 cars were produced making it one of the rarest Porsche 944s produced.944 Turbo (951 LHD/952 RHD)
For the 1986 model year, Porsche introduced the 944 Turbo, known internally as the 951. The Turbo had a turbocharged and intercooled version of the standard 944's engine that generated at 6,000 rpm. In 1987, Car and Driver tested the 944 Turbo and achieved a time of 5.9 seconds. The Turbo was the first Porsche production car utilising a ceramic port liner to retain exhaust gas temperature along with new forged pistons and was also the first vehicle to produce an identical power output with or without a catalytic converter. The Turbo also featured several other changes, such as improved aerodynamics, notably an integrated front bumper. This featured the widest turn signals fitted to any production car, a strengthened gearbox with a different final drive ratio, standard external oil coolers for both the engine and transmission, standard 16 inch wheels, and a slightly stiffer suspension to handle the extra weight. The Turbo also had headers, a crossover pipe and a downpipe made of inconel. The Turbo's front and rear brakes were borrowed from the 911, with Brembo 4-piston fixed calipers and 12-inch discs. Engine component revisions, more than thirty in all, were made to the 951 to compensate for increased internal loads and heat.Changes occurred for the 1987 model year. The North American variant of the 1987 944 Turbo became the first production car in the world to be equipped with driver and passenger side air bags as standard equipment. A low oil level light was added to the dash as well as a speedometer as opposed to the speedometer on the 1986 model year cars. Also included was the deletion of the transmission oil cooler, and a change in suspension control arms to reduce the car's scrub radius. The engine remained the same M44/51 inline-4 as in the 1986 model. ABS became fitted as standard on the Turbo, an option on the regular 944.
In 1988, Porsche introduced the 944 Turbo S with a more powerful engine rated at a maximum power output of at 6,000 rpm and of torque at 4,000 rpm. This higher output was achieved by using a larger KKK K26-8 turbocharger housing and revised engine mapping which allowed maintaining maximum boost until 5,800 rpm, compared to the standard 944 Turbo, the boost would decrease from at 3,000 rpm to at 5,800 rpm. In June 1988, Car and Driver tested the 944 Turbo S and achieved a acceleration time of 5.5 seconds and a quarter-mile time of 13.9 seconds at. Top speed was factory rated at.
The 944 Turbo S' suspension had the "M030" option consisting of Koni adjustable shocks at the front and rear, with ride height adjusting threaded collars on the front struts, progressive rate springs, larger hollow rear anti-roll/torsion bars, harder durometer suspension bushings, larger hollow anti-roll/torsion bars at the front, and chassis stiffening brackets in the front frame rails. The air conditioning dryer lines were routed so as to clear the front frame brace on the driver's side. The 944 Turbo S wheels, known as the Club Sport design, were 16-inch Fuchs forged and flat-dished, similar to the Design 90 wheel. Wheel widths were at the front, and at the rear with a offset; sizes of the Z-rated tyres were 225/50 in the front and 245/45 in the rear. The front and rear fender edges were rolled to accommodate the larger wheels. The manual transmission featured a higher friction clutch disc setup, an external cooler, and a limited-slip differential with a 40% lockup setting. The Turbo S' front brakes were borrowed from the 928 S4, with larger Brembo GT 4-piston fixed calipers and 12-inch discs; rear Brembo brakes remained the same as a standard Turbo.
The 944 Turbo S interior featured power seats for both driver and passenger, where the majority of the factory-built Turbo S models sported a "Burgundy plaid" interior colour but other interior/exterior colours were available. A 10-speaker sound system and equalizer + amp was a common option with the Turbo S and S/SE prototypes. Only the earlier 1986, prototypes featured a "special wishes custom interior" options package.
In 1989 and later production years, the 'S' designation was dropped from the 944 Turbo S, and all of the turbocharged iterations of the 944 featured the Turbo S enhancements as standard, however the "M030" suspension and the Club Sport wheels were not part of that standard. The 944 Turbo S was the fastest production four cylinder car of its time.