Article Item Image

A Star Is Born: The Porsche 911's Iconic Air-Cooled Flat-Six Engine

While the 911 has always been the flag-bearer of the storied Porsche marque, the iconic flat-six engine, and in particular, the air-cooled version is what has endeared the sports car to generations of followers. And rightly so. Not only does the novel firing order produce a unique exhaust note, the flat ‘Boxer’ engine has many interesting features that give it the edge from a design point of view. These features were so compelling to Karl Benz that back in 1896, he devised the first boxer flat engine that he called the “contra”. He named it the contra because its two pistons worked in opposition to one another. Its underlying design principle – both then and now – is that the cylinders should lie flat and slightly offset to each other, on opposite sides of the crankshaft, with opposing sets of pistons working in opposition to one another. The boxer flat engine, particularly in six-cylinder guise, is also inherently smooth, with no primary or secondary out-of-balance forces to dampen. The only downside, compared to a ‘non-boxer’ flat-six layout, is the need for a separate crank throw for each rod and piston, slightly adding to the engine’s length, weight, and cost.   As used in the iconic 911, flat and air-cooled engines with no water-jackets and cooling system are light weight and relatively compact, allowing for a lower centre of gravity. By placing the powertrain at the rear of the vehicle also makes it easier to achieve an aerodynamically sleek front-end, as well as improving traction. In short – the ideal engine for a sports car such as the Porsche 911. The origin of the Porsche family of flat engines can be traced back to the VW Beetle. Its 1.1-litre, four-cylinder engine was the first to be fitted to a Porsche - the 356-001. However the defining moment for Porsche’s iconic flat-six air-cooled engines came at the 1963 Frankfurt motor show when the company unveiled the successor to its four-cylinder 356 sports car. First christened the 901, after an objection by Peugeot, the 901 was renamed the 911. Porsche’s first flat-sixes reached European customers in ’64 and U.S. buyers the following year. Nevertheless, since nothing hindered Porsche from retaining the 901 code for internal use, the 911’s flat-six engine was so named. Hans Mezger’s Design-Brief For The Iconic 901 Flat-Six Engine From the outset of the 901 project, Hans Mezger – an automotive engineer who joined Porsche in 1956 and deserves most of the credit for the engine - had some very clear objectives in mind. Top of the list was a minimum power output. Based on the company’s past success the engine had to produce at least 130 DIN (148 SAE gross) horsepower to match the best engine in the 356. This minimum power requirement automatically disqualified pushrod engines after the 2.0-liter Type 745 designed by Mezger’s predecessor in 1960 failed to produce the desired 148 horsepower. So for the 901 Mezger chose a Single Overhead Camshaft layout with one cam atop each two-valve cylinder head opening both valves via rocker arms. Another non-negotiable was attributed to Ferry Porsche’s “shoemaker, stick to your last” philosophy, which meant keeping the air-cooled, opposed-cylinder layout that had worked perfectly for the VW Beetle and Porsche 356. The reverse of the philosophy - learn from your mistakes - also applied. When an early Type 821 experimental engine suffered oil starvation during hard cornering, Ferry Porsche approved the expense of a dry-sump system that provided several benefits, including reduced losses from the crank spinning in the oil in a ‘wet-sump’, a more compact engine, larger oil reservoir with cooler oil, and eliminating oil-surge during hard acceleration, cornering, and braking. The engine’s displacement was largely determined by Germany’s post–World War II economy that was still on the mend and subjected to high fuel prices. So, In January 1963, Mezger opted to stick with the 356 Carrera’s 2.0-liter displacement. Having decided on the flat layout and displacement he settled for six cylinders as the happy medium between the 356’s four and Porsche’s Type 753 flat-eight racing engine that was under development. Mezger also carried over the 745’s 80-mm bore and 66-mm stroke because he wanted the bore as big as possible to accommodate the larger valves required for good high-rpm breathing. In a shrewd move, Mezger chose to space the bores 118 mm apart, leaving ample room for “bored” engines in future. To assist with cooling, the cylinders supplied by Mahle were a “biral” design, consisting of a thin iron liner surrounded by a liberally finned die-cast aluminum ring. This arrangement, also inherited from the 753 engine, provided ample surface area with cooling airflow over, under, and between the cylinders. The Cool Secret To The Most Successful Air-Cooled Engine Of All Time More than a dozen engine manufacturers exploited air cooling in the 20th century, however, none as successfully as Porsche. Patriarch Ferdinand was an early adopter, beginning with Austrian manufacturer Austro-Daimler’s aircraft-engine design effort in 1912. Air-cooled engines with up to 12 cylinders and 360 horsepower followed for fighter aircraft, airships, helicopters, locomotives, and motorized gun carriages. Because of its simplicity, air cooling was also an obvious choice for the “peoples’ car” conceived in the early 1930s. Dispensing with the coolant, pump, hoses, and radiator trimmed cost and weight and helped make the Beetle’s engine compact enough to mount behind the rear wheels. In the 911, that same location left room for a front stowage compartment and rear jump seats, adding utility to the sports car’s list of attributes. Because of its higher heat capacity water conducts heat from a hot metal surface better than air. To make up for this, designers committed to air cooling have several cooling strategies at their disposal. The most common approach is to attach fins to the cylinders and heads to increase the surface area by up to a factor of 10, or in some designs, even more. However to make sure the significant heat generated by the powerful Porsche 901 would be dissipated Mezger also equipped the engine with what would become Porsche’s ‘trademark’ cooling fan, that directed air over the cylinders and heads. In a perfect world, the cooling airflow would be proportional to the power produced by the engine. However with a fixed ratio crank-driven fan, flow is largely proportional to engine speed. To ensure sufficient airflow under all driving conditions and ambient temperatures, the 911 was equipped with an oversized fan to ensure problem-free motoring. The 901’s 250mm 11-blade cooling fan sat in a fiberglass duct atop the engine and was spun by a V belt at 1.3 times crankshaft speed. Air drawn through decklid vents by the fan was blown through metal ductwork over the cylinders, heads, exhaust manifolds, and oil cooler, then out the bottom of the car. Flow through boxes surrounding the exhaust manifolds also heated the cabin. Mezger’s air-cooled, flat-six boxer engine entered the market weighing 185 kg with an output of 148 horsepower from 1991 cc. The 901 engine’s specific output - horsepower per unit of displacement - topped that of big- and small-block Chevy V-8s, the Mercedes-Benz SL’s SOHC six, and Jaguar’s E-type DOHC six. In 1965, Car and Driver magazine clocked the new 911’s run to 60 mph in 7.0 seconds and measured a top speed of 130 mph. And there was more to come as the air-cooled 901/911 grew and evolved during its long and illustrious life, that continued until the 911 Type 993. In the top-of-the-range 911 Carrera RS, the 3.8-litre air-cooled flat engine achieved 221 kW without turbocharging, while twin turbochargers boosted power to 331 kW.
Article Item Image

The 928 - Pure Comfort and Horsepower

The Porsche 928 grand tourer was made by Porsche from 1978 model year to 1995 model year, during which time it was one of their most expensive offerings.Porsche's marketing slogan "It's about as fast as you can go without having to eat airline food" or "It is as fast as you can go without hiring a flight attendant" from the late 1980s where at one point it was the fastest production road-car in the world, having been recorded at 172mph on the salt flats in Utah in 1986 using an early 928 S4. This particular car was originally white but was sprayed bright red for the record attempt to make it stand out more against the salt in marketing material like videos and posters. Conception By the late 1960s, Porsche had changed significantly as a company, and executives including owner Ferry Porsche were toying with the idea of adding a luxury touring car to the line-up. Managing Director Ernst Fuhrmann was also pressuring Ferdinand to "greenlight" development of the new model in light of concerns that the current flagship at the time, the 911, was quickly reaching its maximum potential where it could soon no longer be improved upon. Slumping sales of the 911 seemed to confirm that the model was approaching the end of its economical life cycle. Fuhrmann envisioned the new range-topping model as being the best possible combination of a sports coupe and a luxury sedan, something well equipped and comfortable enough to be easily driven over long distances that also had the power, poise and handling prowess necessary to be driven like a sports car. This set it apart from the 911, which was a pure sports car.Ordered by Ferry Porsche to come up with a production-feasible concept for his new model, Fuhrmann initiated a design study in 1971, eventually taking from the process the final specs for the 928. Several drivetrain layouts were considered during early development, including rear and mid-engined designs, but most were dismissed because of technical and/or legislative difficulties. Having the engine, transmission, catalytic converter(s) and exhaust all cramped into a small rear engine bay made emission and noise control more difficult, something Porsche was already facing problems with on the 911 and wanted to avoid. After deciding that the mid-engine layout didn't allow enough room in the passenger compartment, a front engine/rear wheel drive layout was chosen. Porsche also feared at the time that the U.S. government would ban the sale of rear-engined cars in response to the consumer outrage over the Chevrolet Corvair, started by Ralph Nader via his book "Unsafe at Any Speed".Porsche engineers wanted a large-displacement motor to power the 928, and prototype units were built with a 5.0 L V8 producing close to 300 hp. Very early units used one four-barrel carburetor, which was eventually tossed in favour of Bosch's K-Jetronic fuel injection system. When increasing concern within the company over the pricing and availability of fuel during the oil crisis of the 1970s became an issue of contention, smaller engines were considered in the interest of fuel economy. Some managers began pushing for development of a 3.3 L 180 hp powerplant they had drawn up specs for, but company engineers balked at this suggestion. Both sides finally settled on a 4.5 L, SOHC 16-valve V8 producing 240 PS (219 hp in North America), which they considered to have an acceptable compromise of performance and fuel economy.The finished car debuted at the 1977 Geneva Motor Show before going on sale later that year as a 1978 model. Although it won early acclaim for its comfort and power, sales were slow. Base prices were much higher than that of the previous range-topping model and its larger size and somewhat odd futuristic styling put off many purists who were more attracted to more compact 911.Fuhrman's replacement, Peter Schutz, decided that the models should be sold side by side, feeling that the 911 still had potential in the company's line-up. Legislation against rear-engined vehicles also didn't materialize. Although the 928 developed an avid fan following, it never sold in the numbers that Fuhrmann had originally predicted and was discontinued in 1995. The size of the market for expensive and extravagant grand tourers has increased since then, and the company is again looking to capture this market with the Porsche Panamera four-door GT. Design The 928 featured a large, front-mounted and water-cooled V8 engine driving the rear wheels. Originally displacing 4.5 L and featuring a single overhead camshaft design, it produced 219 hp (163 kW/222 PS) for the North American market and 240 PS (176 kW/237 hp) in other markets. Porsche upgraded the engine from mechanical to electronic fuel injection in 1980 for US models, although power remained the same. This design marked a major change in direction for Porsche (started with the introduction of the 924 in 1976), whose cars had until then used only rear- or mid-mounted air-cooled flat engines with four or six cylinders.Porsche utilized a transaxle in the 928 to help achieve 50/50 front/rear weight distribution, aiding the car's balance. Although it weighed more than the difficult to handle 911, its more neutral weight balance and higher power output gave it similar performance on the track. The 928 was regarded as the more relaxing car to drive at the time. It came with either a five-speed dog leg manual transmission, or a Mercedes-Benz-derived automatic transmission, originally with three speeds, with four speed from 1983 in North America and 1984 in other markets. More than half of production had the automatic transmission. Exact percentage of manual gearbox cars for entire production run is not known but its believed to be between 25 and 30%.The body, styled by Wolfgang Möbius under guidance of Anatole Lapine, was mainly galvanised steel, but the doors, front wings and bonnet were aluminum. It had a substantial luggage area accessed via a large hatchback. The new polyurethane plastic bumpers were integrated into the nose and tail and covered in body-coloured paint; an unusual feature for the time that aided the car visually and reduced its drag. Porsche opted not to offer a convertible variant but some aftermarket modifiers offer convertible conversions.The 928 qualified as a 2+2, having two small seats in the rear. Both rear seats could be folded down to enlarge the luggage area, and both the front and rear seats had sun visors for occupants. The 928 was also the first vehicle in which the instrument binnacle moved with the adjustable steering wheel, a feature seen more recently on Nissan's 350Z sports car.The 928 included several other innovations such as the "Weissach Axle", an early all-wheel steering system that provides passive rear-wheel steering in certain off-throttle cornering situations, and an unsleeved, silicon alloy engine block made of aluminium, which reduced weight and provided a highly durable cylinder bore. The concept of all-wheel steering was also adopted later on to several Japanese automobiles, including a Japanese-market version of the Toyota Celica, the Mitsubishi 3000GT VR-4 and the second generation Nissan 300ZX.Porsche's design and development efforts paid off during the 1978 European Car of the Year competition where the 928 won against the BMW 7-series and the Ford Granada. The 928 is the only sports car so far to have won this competition, where the usual winners are mainstream hatchbacks and saloons from major European manufacturers. Proof of how advanced the 928 was compared to its contemporaries. Later Variants Porsche introduced a refreshed 928 S into the European market in 1980, although it was summer of 1982 and 1983 model year before the model reached North America. Externally, the S wore new front and rear spoilers and sported wider wheels and tires than the older variant, but the main change for the 928 S was under the hood, where a revised 4.7 L engine was used. European versions debuted with 300 PS (221 kW/297 hp), and were upgraded to 310 PS (228 kW/306 hp) for the 1984 model year. From 1984 to 1986 ROW (Rest Of the World) S model was officially called S2 in UK. North American spec 1983 and 1984 S models used, among other differences, milder camshafts and additional emissions regulation equipment, and were limited to 239 hp (174 kW/242 PS) as a result.As the faster S model was not available in the USA and Canada during the first three years of its existence, a "Competition Package" option was created to allow North American customers to have an S model lookalike with spoilers, 16" flat disc wheels, sport seats, sport springs and Bilstein shocks. Customers could specify paint and interior colors the same way as on a normal 928. The package was available in the 1981 and 1982 model years and was cancelled in 1983 when the S model became available for these markets. Many cars have had S features added by subsequent owners, making original "Competition Package" cars difficult to distinguish without checking option codes.In 1982, two special models were available for different markets. 205 "Weissach Edition" cars were sold in North America. Unusual features were champagne gold metallic paint, matching brushed gold flat disc wheels, two-tone leather interior, a plaque containing the production number on the dash and the extremely collectible three-piece Porsche luggage set. It's believed these cars were not made with S spoilers even though these were available in USA during this time period as part of the "Competition Package." The "Weissach Edition" option was also available for the US market 911 in 1980 and 924 in 1981 model years.140 special "50th Jubilee" 928 S models were available outside the USA and Canada to celebrate the company's 50 year existence as a car manufacturer. This model is also sometimes referred to as the "Ferry Porsche Edition" because his signature was embroidered into the front seats. It was painted meteor metallic and fitted with flat disc wheels, wine red leather and special striped fabric seat centers. Similar 911 and 924 specials were also made for ROW markets.Porsche updated the North American 928 S for 1985, replacing the 4.7 L, SOHC engine with a new 5.0 L, DOHC unit sporting four valves per cylinder and producing 288 hp (215 kW/292 PS). Seats were also updated to a new style. These cars are sometimes unofficially called S3 to distinguish them from 16-valve S models. European models kept a 4.7 L engine, which was slightly more powerful, as standard; a little detuned 32-valve engine together with catalytic converters became an option in some European countries and Australia for 1986. That same year, revised suspension settings, larger brakes with 4-piston calipers and modified exhaust was installed on the 928 S, marking the final changes to old body style cars. ROW models received these changes at beginning of model year while North American cars got them only after close to 900 cars were made, starting from VIN 1000. North American version of this late 1986 model is sometimes referred as S3.5 or S3½ because of these changes. Name is little misleading as more than 2/3 of 1986 North American model production had these updates.The 928 S4 variant debuted in the second half of 1986 as a 1987 model, an updated version of the 5.0 L V8 for all markets producing 320 PS (235 kW/316 hp), spotting a new single-disc clutch in manual gearbox cars, larger torque converter in automatics and fairly significant styling updates which gave the car a cleaner, sleeker look. S4 was much closer in being truly world car than previous models as only major differences between ROW and US models were instrumentation in either kilometers or miles, lighting, front and rear bumber shocks and availability without catalytic converter in many ROW markets. Australian market version was only one with different horsepower rating at 300 PS (221 kW/296 hp) due to preparation for possible low grade fuel. Even this was achieved without engine changes.A "Club Sport" variant which was up to 100 Kg lighter became available to continental Europe and USA in 1988. An SE (sometimes called the S4 Sport), a sort of halfway point between a normally equipped S4 and the more race-oriented "Club Sport," became available to the UK. It's generally believed these Porsche Motorsport engined cars have more hp than the S4. They utilize parts which later became known as GT pistons, cams, engine ECU programs and a stronger, short geared manual gearbox. The automatic gearbox was not available.At beginning of 1989 model year also Australian model received same 320 PS (235 kW/316 hp) setup as other markets. Porsche debuted the 928 GT in the spring of 1989 after dropping the slow selling CS and SE. In terms of equipment, the GT was most like the 928 SE, having more equipment than a Club Sport model but less than a 928 S4 to keep the weight down somewhat. It had the ZF 40% limited-slip differential as standard like the Club Sport and SE before it. Also like the CS and SE, the GT was only available with a manual gearbox. ROW 1989 CS and GT wheels had an RDK tire pressure monitoring system as standard. This was also optional for same year ROW S4. For 1990 model year Porsche made RDK and a 0-100% variable ratio limited-slip called PSD (Porsche SperrDifferential) standard in both GT and S4 models for all markets. This system is much like the one from the 959 and gives the vehicle even more grip. In 1990 the S4 was no longer available with a manual gearbox.The S4 and GT variants were both cut at end of 1991 model year, making way for the final version of the 928. The 928 GTS came for sale in late 1991 as a 1992 model in Europe and in spring of 1992 as an early 1993 model in North America. Changed bodywork, larger front brakes and a new, more powerful 5.4 L, 350 PS (257 kW/345 hp) engine were the big advertised changes; what Porsche wasn't advertising was the price. Loaded GTS models could eclipse $100,000 USD in 1995, making them among the most expensive cars on the road at the time. This severely hampered sales despite the model's high competancy and long standard equipment list. Porsche discontinued the GTS model that year after shipping only 77 of them to the United States. Total worldwide production for all years was a little over 61,000 cars.Second-hand models have largely fallen in value, the result of generally high maintenance costs due largely to spare parts that are expensive to manufacture. The earliest versions, however, especially those models with the Bosch K-Jetronic (CIS) injection system, have few electronic components and therefore can be repaired more easily provided spare parts can be found.The GTS model has retained a high value however, and as of 2006 the price for all variants is apparently starting to creep upwards (Classic Motorsports, March, 2006 issue, p. 38). A great community dedicated to the 928 exists online even today, and the car has won a huge fan base. The 928 was such a powerful vehicle in its day that even models 25+ years old are able to outperform current sport/grand-touring models of various manufacture.With the release of the Cayenne sports utility vehicle, Porsche has met with renewed success with a front-engined, V8-powered model. The company's 2005 announcement that a new V8-powered 4-door grand tourer model called Panamera would be launched in 2009 fueled rumours and fan speculation of a reborn 928. Although the Panamera will be a 4-door model, Road and Track magazine published a speculative piece in their April 2006 issue in regards to the possibility of a new, 928-esque coupe that may debut on a shortened version of the Panamera's platform sometime around the 2011 or 2012 model years. Although feasible, this is pure speculation as of 2006. The article seemed to indicate a re-use of the 928 nameplate although Porsche's recent tendency to give non-numerical names to their vehicles and a desire to separate the vehicle from past models may preclude the possibility of calling the vehicle 928.Also noteworthy is that there are several manufacturers of supercharger and turbo kits specifically for the 928. The stock engine for any year is capable of handling significant power increases without part failure. More owners have opted for supercharging their vehicles as the conversion is reasonably straight forward whereas the fitting of two turbo chargers on each of the exhaust manifolds has caused problems because of the lack of space. Styling Changes Styling was the same from 1978 through 1979 and the body lacked both front and rear spoilers. From in North America) through 1986, front and rear spoilers were present on "S" models, rear spoilers were integrated into the hatch. From 1987 through 1995, the front spoiler is integrated into the nose and the rear spoiler became a separated wing rather than an integrated piece, and side skirts were added. The rear tail-light configuration was also different from previous versions. GTS model had wider rear fenders added to give more room for 9" wide wheels.Another easily noticeable visual difference between versions is the style of the rims. Early 928s had 15" or 16" "phone dial"-style rims, while most 1980s 928s had 16" slotted "flat disc"s, CSs, SEs and 1989 GTs had 16" "Club Sport", later GTs had 16" "Design 90" style which were also option on same period S4s, the GTS used two variations of the 17" "Cup" rims. Information detailing the evolution through the model years The evolution of the 928 during its 18 years of production is quite subtle, and often confuses individuals interested in purchasing a 928. The tables below show the major differences, which were largely made to the nose, tail, interior, engine and rims.Information detailing the evolution through the model years:-1978Model designation: 928Engine displacement: 4.5 LValves: 16Bosch K-Jetronic injectionPower: 219 hp (163 kW) North America / 240 PS (177 kW) ROW (rest of world)1979Model designation: 928Engine displacement: 4.5 LValves: 16Bosch K-Jetronic injectionPower: 219 hp (163 kW) North America / 240 PS (177 kW) ROWChanges:Battery box integrated as part of the body, was previously mounted to gearbox. Gearbox shocks deleted.1980Model designation: 928 North America/928 and 928 S ROWEngine displacement: 4.5 L/4.7 L (S)Valves: 16Power: 220 hp (163 kW) North America / 240 PS (177 kW) (4.5) and 300 PS (221 kW) (4.7 S) ROWChanges:Bosch L-Jetronic injection to North America.Front & rear spoilers on S model.Manual gearbox changed during model year requiring shorter torque tube also."S" brakes into use during model year in all ROW cars.1981Model designation: 928 North America/928 and 928 S ROWEngine displacement: 4.5 L/4.7 L (S)Valves: 16Power: 220 hp (163 kW) North America / 240 PS (177 kW) (4.5) and 300 PS (221 kW) (4.7 S) ROWChanges:"Competition Package" option available in US.1982Model designation: 928 North America/928 and 928 S ROWEngine displacement: 4.5 L/4.7 L (S)Valves: 16Power: 220 hp (163 kW) North America / 240 PS (177 kW) (4.5) and 300 PS (221 kW) (4.7 S) ROWChanges:Vibration damper added into torque tube between 2nd and 3rd support bearing on manual gearbox cars and behind 2nd bearing on automatics. Reverse gear lock added to manual gearbox."S" brakes into use in US models.205 "Weissach Edition" made for US market.140 "50th Jubilee" 928 S made for ROW markets.4.5 L ROW model and US "Competition Package" option dropped from production at end of 1982 model year.1983Model designation: 928 SWeight: 3300 lb/1500 kgEngine displacement: 4.7 LValves: 16Power: 239 hp (174 kW) @ 5200 rpm North America / 300 PS (221 kW) ROWChanges:New style hydraulic motor mounts. Engine shocks deleted at same time.4-speed automatic transmission for North America. Cars body and torque tube changed to accommodate longer gearbox.1984Model designation: 928 S/928 S2 UKWeight: 3300 lb/1500 kgEngine displacement: 4.7 LValves: 16Power: 239 hp (174 kW) @ 5200 rpm North America / 310 PS (228 kW) ROWChanges:S model renamed S2 in UK market.Bosch LH-Jetronic injection and 4-speed automatic transmission added to the ROW model. Torque tube shortened like on US model in previous year.ABS brakes optional for the first time in Porsche.At 146 mph (235 km/h) US model top speed, Porsche boldly claims the 928 S to be "the fastest street legal production car sold in the US".Important safety related change to front suspension lower ball joints on all cars in September 1983.EZF ignition system using dual distributors makes debut on ROW cars. This allows higher 10.4:1 compression and increased torque. Compression change done in middle of model year once 10.0:1 compression ratio resulting piston stock were used up in production.1985Model designation: 928 S/928 S2 UKWeight: 3300 lb/1500 kgEngine displacement: 5.0 L North America/4.7 L ROWValves: 32 North America/16 ROWPower: 288 hp/292 PS (215 kW) North America / 310 PS/306 hp (228 kW) ROWChanges:New 5.0 liter 32-valve LH-Jetronic injection and EZF ignition 288 hp engine for US market. Top speed is now in excess of 155 mph (250 km/h) for US models also.LH-Jetronic control box design changed in ROW cars.New style front seats. Redesigned more modern looking door panels when multi speaker stereo was ordered. Gearbox synchromesh changed to Borg Warner design and shorter gear lever, improving driveability on manual transmission cars. Shims left out from front end of torque tube drive plate in automatic cars, this sometimes cause engine thrust bearing failures.Radio antenna moved to imbedded windshield wire.1986Model designation: 928 S/928 S2 UKWeight: 3300 lb/1500 kgEngine displacement: 5.0 L North America/4.7 or 5.0 L ROWValves: 32 North America/16 or 32 ROWPower: 288 hp/292 PS (215 kW) North America / 310 PS/306 hp (231 kW) (4.7) or 288 PS/284 hp (215 kW) (5.0) ROW / 275 PS/272 hp (202 kW) (4.7) Sweden and SwitzerlandChanges:Lower compression (9.3:1 vs 10.0:1 for US version) 32-valve engine optional for some ROW markets with catalytic converter, standard in Australia. Compression change was done with different shape piston tops.Lower compression (9.3:1 vs 10.4:1 for normal ROW version) 16-valve engine for Sweden and Switzerland. Compression change was done with different shape piston tops. Only together with automatic transmission. Engine number is same M28/22 as in high compression 16V engines. Only outside indication for different pistons is option code M151.ABS brakes became standard for all markets during model year production.So called "S4" suspension and brakes in all 1986 ROW cars, from VIN 1001 forward in North America.No US models made with VIN ending between 0938 and 1000 due to suspension and brake parts change.1987Model designation: 928 S4Weight: 3500 lb/1590 kgEngine displacement: 5.0 LValves: 32Power: 316 hp/320 PS (236 kW) ROW and North America / 300 PS/296 hp (221 kW) AustraliaChanges:New style front & rear bumpers and rear wing spoiler. Redesigned front and rear bumper light assemblies. Body changed compared to earlier models to accommodate larger rear lamps, rear sears area modified to give room for new torque converter.Different style pistons, cylinder heads, camshafts, intake and larger valves compared to earlier 5.0 L engines. Nominal compression ratio 10.0:1, true ratio between 9.4:1 and 10.0:1 depending on parts used. Cylinder head studs used in all earlier engines replaces with bolts making it easier to remove heads while engine is in engine bay.Updated LH-Jetronic injection and ignition changed to EZK system, two knock sensors added to engine. Single disk clutch on manual transmission cars, larger torque converter on automatics.Upwards folding rear spoiler and piston oil squirters in engine block on early cars only.Different horsepower rating for Australia due to possible low grade fuel.1988Model designation: 928 S4 and 928 CS North America/928 S4 and 928 CS ROW/928 S4 and 928 SE UKEngine displacement: 5.0 LValves: 32Power: 316 hp/320 PS (236 kW) (S4, CS and SE) ROW and North America / 300 PS/296 hp (221 kW) (S4) AustraliaChanges:Lighter 928 CS (Club Sport) version available in Continental Europe and US, 928 SE (S4 Sport) in UK. Only model year for US CS and UK SE.Stronger torque tube with 3mm thicker center shaft for automatics.Pistons with strengthened skirt into use in February 1988. Oil drainage improved in piston skirts.1989Model designation: 928 S4 and 928 GT North America/928 S4, CS and GT ROW/ 928 S4 and GT UKEngine displacement: 5.0 LValves: 32Power: 316 hp/320 PS (236 kW) (S4) / 326 hp/330 PS (243 kW) (GT)Changes:Digital trip computer/warning system added to dashboard, ignition circuit monitor system added.For Australian cars same fuel and ignition maps resulting same horsepower rating as in other markets.Shorter final drive on North American manual transmission S4, same ratio as used in ROW 5-speed cars to simplify production.RDK tyre pressure monitoring system optional on ROW S4, standard on ROW CS and GT.Thicker cylinder head casting taken into use early in model year to strengthen head against cracking. Longer head bolts needed because of the change.ROW 928 CS dropped from production during the middle of the model year at the end of 1988.February 1989, manual transmission only GT debuts as a more sporting version on all markets.1990Model designation: 928 S4/928 GTEngine displacement: 5.0 LValves: 32Power: 316 hp/320 PS (236 kW) (S4) / 326 hp/330 PS (243 kW) (GT)Changes:GT pistons into use in S4 also resulting true 10.0:1 compression ratio for all engines.RDK tyre pressure monitoring system standard on all cars. Computer controlled 0-100% PSD locking differential added to both models.S4 no longer available with manual gearbox.Dual airbags now standard across all Porsche models in USA. Driver and front passenger airbag optional in LHD ROW cars, only drivers side bag available in RHD markets.1991Model designation: 928 S4/928 GTEngine displacement: 5.0 LValves: 32Power: 316 hp/320 PS (236 kW) (S4) / 326 hp/330 PS (243 kW) (GT)Changes:Improvements to steering rack, soundproofing, front cooling flaps deleted, new style shift knob with integrated leather booth in manual gearbox cars, etc.Two airbags as standard in ROW LHD models during model year production, at same time drivers side airbag standard in RHD models while passenger side bag still not available.1992Model designation: 928 GTSEngine displacement: 5.4 LValves: 32Power: 345 hp/350 PS (257 kW)Changes:Engine grows to 5.4 L due to longer stroke crankshaft and different compression height and 10.4:1 ratio pistons, improved cooling in exhaust side at cylinder heads, bodywork updated with flared rear fenders and so called cup mirrors. "big black" front brakes, significantly larger than "S4" version. Stronger manual gearbox with differential driven oil pump and front mounted oil cooler.GTS became available in North America at February 1992 as early 1993 model. These cars use same parts as 1992 ROW models.1993Model designation: 928 GTSEngine displacement: 5.4 LValves: 32Power: 345 hp/350 PS (257 kW)Changes:Cylinder block lower half studs replaced with bolts. Engine piston rings changed to limit oil consumption and pistons changed to strengthen skirt area. Minor update to clutch.Passenger side airbag added to RHD cars.1994Model designation: 928 GTSEngine displacement: 5.4 LValves: 32Power: 345 hp/350 PS (257 kW)Changes:Connecting rods changed to stronger design part. Cabin pollen filter added. Dynamic kickdown to automatics. Wheel design changed to Cup II, RDK deleted at same time.First 19 US models were made already in spring of 1993, months before when normal model year change occurs in July. These cars still have previous model year parts like Cup I wheels and do not have 1994 model updates.1995Model designation: 928 GTSEngine displacement: 5.4 LValves: 32Power: 345 hp/350 PS (257 kW)Changes:Special model available in some ROW markets containing wider front fenders made out of steel and 8" wide front wheels. Only available with automatic gearbox, Iris blue metallic and Amazon green metallic color with Classic grey leather interior.Manual gearbox car production ended some months before last automatic cars were made.
Article Item Image

The 924 - the VW that saved Porsche from financial ruin!

The Porsche 924 was produced by Porsche from 1976 to 1988. A two-door, 2+2 coupé, the 924 replaced the 914 as the company's entry-level model, and was the model that finally retired the 912. It was the first Porsche model powered by a water-cooled, front-mounted engine to make production, although the similarly-configured 928 was designed before the 924. The front-engine, rear wheel drive arrangement was normal for most other manufacturers, but it was unusual for Porsche, who had previously only used mid or rear-mounted engines of a boxer configuration, all of which had been air-cooled.The first official appearance of the 924 took place in November 1975 (as a press launch rather than a motorshow appearance) at the harbour at La Grande Motte, Camargue in the south of France. The model was a success and not only helped to take Porsche out of financial ruin, but created the revenue stream needed to continue building and developing the 911. The 924 was replaced by the 944 in 1982 in the US market, but continued to be produced until 1985 in the Rest of World market.For the 1986 to 1988 model years the car aqquired the powerplant from the 944 model and became the Porsche 924S. 924 The 924 was originally intended to be Volkswagen's flagship coupé sports car. Volkswagen commissioned Porsche to design the car (VW project number 425), who developed a fresh chassis and transmission that would work with an existing Audi I4 engine. They also handled the suspension and the interior and exterior design. Porsche decided on a rear wheel drive layout, and chose a rear transaxle to help provide 48/52 front/rear weight distribution. This slight rear weight bias, despite the front mounted engine, aided both traction and brake balance.Due to growing concern over the 1973 oil crisis and a change of directors at Volkswagen, they put the 425 project on hold, eventually dumping it entirely after their decision to move forward with the Volkswagen Scirocco model instead. Porsche, who needed a model to replace the 914, made a deal with Volkswagen leadership, agreeing to buy the design for an undisclosed figure—some suggest 100 million DM, others say 160 million—but most agree it was less than the amount Volkswagen paid Porsche to design it.The deal specified that the car would be built at the ex-NSU factory in Neckarsulm located north of the Porsche headquarters in Stuttgart, the Volkswagen employees would do the actual production line work and that Porsche would own the design. It became one of Porsche's best-selling models to date, and the relative cheapness of building the car made it both profitable and fairly easy for Porsche to finance.The original design used an Audi-sourced four-speed manual transmission for the 924 mated to VW's EA831 2.0 L I4 engine, previously used in the Audi 100 and Volkswagen LT van and producing 95 hp (71 kW) in North American trim. This was brought up to 110hp (87kw) in mid-1977 with the introduction of a catalytic converter, which reduced the need for power-robbing smog equipment. The four-speed manual was the only transmission available for the initial 1976 model. An Audi three speed automatic was offered starting with the 1977.5 model.European models, which didn't require any emissions equipment, made 125 hp. They also differed visually from the US spec model by not having the US cars low-speed impact bumpers and the round reflectors on each end of the body.A 5-speed transmission, available starting in 1979, was a "dogleg" Porsche unit, with first gear below reverse on the left side. This was troublesome and was quickly replaced for 1980 with a normal H-pattern Audi five speed. The brakes were solid discs at the front and drums at the rear. The car was criticised in Car and Driver magazine for this braking arrangement, which was viewed as a step backward from the 914's standard four-wheel disc brakes. However, four wheel disc brakes, five stud hubs and alloys from the 924 Turbo were available on the base 924 as an "S" package starting with the 1980 model year.The overall styling was penned by Dutchman Harm Lagaay, a member of the Porsche styling team, with the hidden headlights, sloping bonnet line and grille-less nose giving the car its popular wedge shape. The car went on sale in the USA in July 1976 as a 1977 model with a base price of $9,395. Porsche made small improvements to the 924 each model year between 1977 and 1985, but nothing major was changed. 924 Turbo Porsche executives soon recognized the need for a higher-performance version of the 924 that could bridge the gap between the basic 924 and the 911s. Having already found the benefits of turbochargers on several race cars and the 1975 911 Turbo, Porsche chose to use this technology for the 924, eventually introducing the 924 Turbo as a 1978 model.Porsche started with the same Audi-sourced 2.0 L I4, designed an all new cylinder head (which was hand assembled at Stuttgart), dropped the compression to 7.5:1 and engineered a KKK K-26 turbocharger for it. With 10 psi (70 kPa) boost, output increased to 170 hp (127 kW). The 924 Turbo engine assembly weighed about 65lbs more, so front spring rates and anti-roll bars were revised. Weight distribution was now 49/51 compared to the original 924 figure of 48/52 front to rear.In order to help make the car more functional, as well as to distinguish it from the naturally-aspirated version, Porsche added a NACA duct in the hood and air intakes in the badge panel in the nose, 15-inch spoke-style alloy wheels, four-wheel disc brakes with 5 stud hubs and a five-speed transmission. Forged 16" flat wheels from the 928 were optional.Internally, Porsche called it 931 (left hand drive) and 932 (right hand drive), much like the 911 Carrera Turbo, which had been "Type 930". These designations are commonly used by 924 aficionados.The turbocharged engine allowed the 924's performance to come surprisingly close to that of the 911 SC (180 bhp), thanks in part to a lighter curb weight, but it also brought reliability problems.Intense heat in the engine bay lead to short turbocharger life and turbo-related seal and seat problems. To fix the problems, Porsche released a revised 924 Turbo series 2 (although badging still read 924 Turbo) in 1981. By using a smaller turbocharger running at increased boost, slightly higher compression of 8:1 and an improved fuel injection system with DITC ignition triggered by the flywheel, reliability improved and power rose to 177 hp (132 kW).After a successful sales run of both naturally-aspirated and turbo models, in 1981 Porsche decided to surprise everyone and a new 924 variant was unveiled at Le Mans 24 Hours.By adding an intercooler, increasing compression to 8.5:1 as well as various other little changes, Porsche was able to develop the 924 Turbo into the race car they had wanted, dubbing it the 924 Carrera GT.Visually it differed to the 931 in that it had polyurethane plastic front and rear flared guards, a polyurethane plastic front spoiler, a top mounted air scoop for the intercooler, a much larger rubber rear spoiler and a flush mounted front windscreen. It lost the 931's NACA duct in the hood but retained the air intakes in the badge panel. This more aggressive styling was later used for as motivation for the 944.In order to comply with the homologation regulations, the 924 Carrera GT and later 924 Carrera GTS were offered as road cars as well, producing 210 and 245 hp (157 and 183 kW) respectively. Clubsport versions of the GTS were available with a factory included Matter rollcage and race seats. 924 Carrera GT variations were known by model numbers 937 (left hand drive) and 938 (right hand drive).The ultimate development of the 924 in its race trim was the 924 Carrera GTR race car, which produced 375 hp (280 kW) from a highly modified version of the 2.0 L I4 used in all 924s except for the 944 Carrera GTP which used a highly modified as yet unreleased 944 2.5 litre DOHC 16v Porsche unit. This last model variant came 7th overall at Le Mans 24 Hours and spent the least time out of any other car in the pits.Production of the 924 Turbo ceased in 1982 except for the Italian market which lasted until 1984. This is due to the restrictions on engines larger than 2 liters, putting the 2.5 liter 944 into a much higher tax category. 924S In 1986 the 924S was released. Porsche realised with the 944's prices increasing with new standard features and options, they were losing their place as Porsches entry-level model car. While the 924 had always been available in other markets, Porsche decided to re-introduce the 924 to the American market with an initial price under $20,000. The 924S had an old-spec 944 engine producing 150 bhp and drivetrain but with a normal slim 924 body. It also retained the original 924's spartan, VW-like interior. In 1987 the 924S Le Mans (or Special Edition) was made available in limited numbers with a 944 spec 163hp engine, uprated suspension and cosmetically upgraded interior and exterior. This special 924 had manual windows, no sunroof, and no air conditioning to save weight, although you could order one with air conditioning if you so wished.In 1988, the final year of production for the 924S, the power for all models was brought up to 163 hp (122 kW). This made the 924S faster than the base 944 due to its lighter weight and more aerodynamic body. Due to unfavorable exchange rates in the late 1980s, Porsche decided to focus on upmarket models. They dropped the 924S for the 1989 model year, and stopped producing the base 944 later that same year
Article Item Image

The Iconic 911

The famous, distinctive and durable Porsche 911 has undergone continuous development since its introduction in 1964. Mechanically it is notable for being rear engined and, until the introduction of the all-new Type 996 in 1999, air-cooled.Since its inception the 911 has been modified, both by private teams and the factory itself, for racing, rallying and other types of automotive competition. It is often cited as the most successful competition car ever, especially when its variations are included, mainly the powerful 935.In the international poll for the award of Car of the Century, the 911 came fifth after the Ford Model T, the Mini, the Citroën DS and the Volkswagen Beetle. It is the most successful surviving application of the air (or water) cooled opposed rear engine layout pioneered by its original ancestor, the Volkswagen Beetle. The air cooled series of engines (1964 - 1998) The Porsche 911 was developed as a much more powerful, larger, more comfortable replacement for the Porsche 356, the company's first model, and essentially a sporting evolution of the Volkswagen Beetle. The new car made its public debut at the 1963 Internationale Automobil-Ausstellung, better known to English speakers as the Frankfurt motor show.It was designated as the "Porsche 901" (901 being its internal project number). Peugeot protested on the grounds that they owned the trademark to all car names formed by three numbers with a zero in the middle. So, before production started, the new Porsche had its name changed to 911. It went on sale in 1964. 911 2.0-litre / O, A and B series (1964-1969) The earliest editions of the 911 had a 130 PS (96 kW) six-cylinder engine, in the "boxer" configuration like the 356, air-cooled and rear-mounted, displaced 1991 cc compared with the 356's four-cylinder 1600 cc unit. The car had four seats although the rear seats are very small, and the car is usually called a 2+2 rather than a four-seater (the 356 was also a 2+2). It was mated to a five speed manual "Type 901" transmission. The styling was largely by Ferdinand "Butzi" Porsche, son of Ferdinand "Ferry" Porsche. Erwin Komenda, the leader of the Porsche car body construction department, was also involved in the design.The 356 came to the end of its production life in 1965, but there was still a market for a 4-cylinder car, particularly in the USA. The Porsche 912, introduced the same year, served as a direct replacement. It used the 356's 4-cylinder, 1600 cc 90 PS (66 kW) engine but wore the 911 bodywork.In 1966 Porsche introduced the more powerful 911S, the engine's power raised to 160 PS (118 kW). Alloy wheels from Fuchs, in a distinctive 5-leaf design, were offered for the first time. In motorsport at the same time, installed in the mid-engined Porsche 904 and Porsche 906, the engine was developed to 210 PS (154 kW).In 1967 the Targa version was introduced. The Targa had a removable roof panel, a removable plastic rear window (although a fixed glass version was offered alongside from 1968) and a stainless steel-clad roll bar. (Porsche had, at one point, thought that the NHTSA would outlaw fully open convertibles in the US, an important market for the 911, and introduced the Targa as a "stop gap" model.) The name "Targa" came from the Targa Florio road race in Sicily, in which Porsche had notable success: victories in 1956, 1959, 1960, 1963, 1964, 1966, 1967, 1968, 1969, 1970 and 1973.The 110 PS (81 kW) 911T was also launched in 1967 and effectively replaced the 912. The staple 130 PS (96 kW) model was renamed the 911L. More excitingly, the 911R was produced in tiny numbers (20 in all). This was a lightweight racing version with thin aluminum doors, a magnesium crankcase, twin-spark cylinder heads, and a power output of 210 PS (154 kW).In 1969 the B series was introduced: the wheelbase for all 911 and 912 models was increased from 2211 mm to 2268 mm, an effective remedy to the car's nervous handling at the limit. The overall length of the car did not change: rather, the rear wheels were relocated aft. Fuel injection arrived for the 911S and for a new middle model, 911E. A semi-automatic Sportomatic model, composed of a torque converter, an automatic clutch, and the four speed transmission, was added to the product lineup. 911 2.2-litre / C and D series (1970-1971) For the 1970 model year the engines of all 911s was increased to 2195 cc. Power outputs were uprated to 125 PS (92 kW) in the 911T, 155 PS (114 kW) in the 911E, and 180 PS (118 kW) in the 911S. The 912 was discontinued, thanks to the introduction of the Porsche 911T as an entry model.The 2.2 L 911E was called "The secret weapon from Zuffenhausen". Despite the lower power output of the 911E (155 PS) compared to the 911S (180 PS) the 911E was quicker in acceleration up to 160 km/h (100 mph). 911 2.4-litre / E and F series (1972-1973) The 1972-1973 model years consisted of the same models of 911, the entry level T, the midrange E and the top of the line S. However, all models got a new, larger 2341 cc/142 in³ engine. This is universally known as the "2.4 L" engine, despite its displacement being closer to 2.3 litres, perhaps to emphasize the increase over the 2.2. The new power ratings were 130 PS (96 kW), or 140 hp (104 kW) in the U.S., for the T, 165 PS (121 kW) for the E and 190 PS (140 kW) for the S.The 911E and 911S used mechanical fuel injection (MFI) in all markets. The 911T was carbureted, except in the US where it also used MFI, which accounts for the 7 kW power difference between the two. In January, 1973, US 911Ts were switched to the new K-Jetronic CIS (Continuous Fuel Injection) system from Bosch. These CIS-powered cars are usually referred to as "1973.5" models by enthusiasts.With the power and torque increases, the 2.4 L cars also got a newer, stronger transmission, identified by its Porsche type number 915. Derived from the transmission in the Porsche 908 race car, the 915 did away with the 901/911 transmission's "dog-leg" style first gear arrangement, opting for a traditional H pattern with first gear up to the left, second gear underneath first, etc. Some say this was because the dog-leg shift to second gear was inconvenient for in town driving, other say it was due to Porsche’s desire to put 5th gear outside the main transmission housing where it could easily be changed for different races. The Sportomatic transmission was still available, but only as a special order.In 1972 a tremendous effort was made to improve the handling of the 911. Due to the 911's unusual engine placement (rear-mounted, with most of the vehicle's weight concentrated over the rear axle) early 911's were prone to over steer when driven at the limit, and could easily spin in the hands of an inexperienced driver. In an attempt to remedy this, Porsche relocated the oil tank from its position behind the right rear wheel to in front of it. This had the effect of moving the weight of almost 8 liters of oil from outside the wheelbase to inside, improving weight distribution and thus, handling. To facilitate filling of the oil tank, Porsche installed an oil filler door (much like the fuel filler door on the left front fender) on the right rear quarter panel. Unfortunately, this unique design was scrapped after only one year, some say because inattentive petrol station attendants were putting petrol in the oil tank. The oil tank was subsequently moved back to its original position for the 1973 model year, and remained there until it was moved back within the wheelbase for the 964 models.911S models also gained a discreet spoiler under the front bumper to improve high-speed stability. With the car's weight only 1050 kg (2315 lb), these are often regarded as the best classic mainstream 911s. For racing at this time, the 911 ST was produced in limited numbers (the production run for the ST only lasted from 1970 to 1971.) The cars were available with engines of either 2466 cc or 2492 cc, producing 270 PS (199 kW) at 8000 rpm. Weight was down to 960 kg. The cars had success at the Daytona 6 Hours, the Sebring 12 Hours, the 1000Km Nurburgring and the Targa Florio.911 Carrera RS (1973 and 1974)These models, much prized by collectors, are considered by many to be the greatest all-time classic 911s. RS means Rennsport in German, meaning motorsport or circuit racing. The Carrera name was reintroduced from the 356 Carrera which had itself been named after Porsche's victories in the Carrera Panamericana races in Mexico in the 1950s. The RS was built so that Porsche could enter racing formulae that demanded that a certain minimum number of production cars were made. Compared with a standard 911S, the Carrera 2.7 RS had a larger engine (2687 cc) developing 210 PS (154 kW) with MFI, revised and stiffened suspension, a "ducktail" rear spoiler, larger brakes, wider rear wheels and rear wings. In RS Touring form it weighed 1075 kg, in Sport Lightweight form it was about 100 kg lighter, the saving coming from the thin-gauge steel used for parts of the bodyshell and also the use of thinner glass. In total 1580 were made, comfortably exceeding the 500 that had to be made to qualify for the vital FIA Group 4 class. 49 Carrera RS cars were built with 2808 cc engines producing 300 PS.In 1974, Porsche created the Carrera RS 3.0 with K-Jetronic Bosch fuel injection producing 230 PS. It was almost twice as expensive as the 2.7 RS but offered a fair amount of racing capability for that price. The chassis was largely similar to that of the 1973 Carrera RSR and the brake system was from the Porsche 917. The use of thin metal plate panels and a spartan interior enabled the shipping weight to be reduced to around 900 kilograms.The Carrera RSR 3.0 and Carrera RSR Turbo (its 2.1 L engine due to a 1.4x equivalency formula) were made in tiny numbers for racing. The turbo car came second at the 24 Hours of Le Mans in 1974, a significant event in that its engine would form the basis of many future Porsche assaults on sportscar racing, and can be regarded as the start of its commitment to turbo charging. 911 2.7-litre / G, H, I and J series (1974-1977) The 1974 model year saw 3 significant changes. First, the engine size was increased to 2687cc giving a welcome increase in torque. Second, was the introduction of impact bumpers to conform with low speed protection requirements of US law, these bumpers being so successfully integrated into the design that they remained unchanged for 15 years. Thirdly, the use of K-Jetronic CIS Bosch fuel injection in 2 of the 3 model line up - the 911 and 911S models, retaining the narrow rear wings of the old 2.4, now had a detuned version of the RS engine producing 150 and 175 PS respectively. However the top of the range Carrera 2.7 , now a regular production model, inherited the wider rear wings of the RS together with its 210 PS MFI engine and was indeed mechanically identical to the 1973 RS and still weighed the same at 1075 kg. All 3 models were given high backed front seats.The 930 Turbo was introduced in 1975 (see below).The Carrera 3.0 was introduced in 1976 with what was essentially the Turbo's 2994 cc engine minus the turbocharger, and with K-Jetronic CIS although now developing 200 PS (147 kW).The well known problem of pulled cylinder head studs with the K-Jetronic 2.7 engine only occurred in hot climates. This emerged in 1975 in California where thermal reactors, aimed at reducing emissions, were fitted below the cylinder heads thus causing massive heat build up around the magnesium crankcase and then made worse by the lean running K-Jetronic CIS. The fitting of a 5 blade engine fan instead of the usual 11 blade further compounded the situation. Bearing in mind Porsche's largest market being the USA, the 930 Turbo, Carrera 3.0 and all subsequent models used aluminium alloy crankcases which were around 15 lbs heavier.The Bosch K-Jetronic CIS varied fuel pressure to the injectors dependent on the mass airflow. While this system was exceedingly reliable, it did not allow the use of as "hot" cams as MFI or carburettors allowed. Therefore the 911S's horsepower decreased from 190 to 175 despite the displacement increase from 2.4 to 2.7 L. However, the engine did have increased drivability. The 210 PS Carrera 2.7 with MFI was not sold in the US owing to emission regulations -instead they received a 'Carrera' fitted with a 911S engine producing 175 PS, later reduced to 165, and in California even down to 160 PS.Also produced for the 1976 "model year", for the U.S. market, was the 912E, a 4-cylinder version of the 911 like the 912 that had last been produced in 1969. It used the I-serced. In 1976 the Porsche 924 took this car's place for the 1977 "model year" and beyond. The power was supplied by a 4 cylinder high performance fuel injection motor also used in the 411 Volkswagen. Less than 6000 were built.Position vis-à-vis the Porsche 928Although Porsche was continuing development of the 911, executives were troubled by its declining sales numbers and in 1971 approved work on the Porsche 928. Larger, with a front-mounted V8 engine that was considerably more powerful than the contemporary 911's, the 928 was not only designed to eclipse its performance, it was designed to be a more comfortable car, a sporty grand tourer rather than a focused sports car. The 928 sold reasonably well, and managed to survive from its introduction in 1977 until 1995. Throughout its 17 years, despite its capabilities on the road, it never outsold the 911. Notably, it achieved little success in racing. 911 Turbo (Type 930) (1974–1989) In 1974 Porsche introduced the first production turbocharged 911. Although called simply Porsche 911 Turbo in Europe, it was marketed as Porsche 930 (930 being its internal type number) in North America. The body shape is distinctive thanks to wide wheel-arches to accommodate the wide tires, and a large rear spoiler often known as a "whale tail" on the early cars, and "tea-tray" on the later ones. Starting out with a 3.0-litre engine (260 PS or 191 kW), it rose to 3.3 L (300 PS or 221 kW) for 1978. The early cars are known for extreme turbo lag.Production figures of the car soon qualified its racing incarnation for FIA Group 4 competition as the Porsche 934, of 1976. Many participated at Le Mans and other races including some epic battles with the BMW 3.0 CSL "Batmobile". The wilder Porsche 935, a more highly tuned car in FIA Group 5 and evolved from the 2.1 L RSR Turbo of 1974, was campaigned in 1976 by the factory and won Le Mans in 1979. Private teams continued to compete successfully with the car until well into the 1980s.As demand for the Turbo soared in the late 1980s, Porsche introduced novelty variants including a slant-nose version, while not significantly improving the range mechanically. Although these cars could be sold for extraordinary premiums over the standard models, the company's reluctance to invest in research and development of the entire 911 line at that time turned out to be an almost fatal decision not only for the 911, but for the entire company.Only in its last production year the 930 was equipped with a five-speed gearbox. Before, the five-speed gearboxes of the naturally-aspirated cars were not strong enough to cope with the torque of the turbo engines. With the four-speed gearbox the 930 was capable of exceeding 200 km/h (125 mph) in third gear.There have been turbocharged variants of each subsequent generation of 911. Four-wheel-drive was standard from the 993 Generation and on, except for the lightweight GT2. 911 SC (1978-1983) The new 3.0 litre 911 SC (2994 cc) was now the basic model. It was in effect a Carrera 3 (known as a 911S in the US) detuned to provide 180 PS.The "SC" designation was reintroduced by Porsche for the first time since the 356 SC (as distinguished from the race engined 356 Carrera). No Carrera versions were produced, the 930 Turbo remaining at the top of the range. Yet, the weight of the extra equipment on these cars was blunting performance compared with what would have been expected from earlier, lighter cars with the same power output. So power was increased to 188 PS for 1980, then finally to 204 PS. (see below)SCs sold in the UK could be specified with the Sport Group Package (UK) which added stiffer suspension, the rear spoiler, front rubber lip and black Fuchs wheels.In 1981 a Cabriolet concept car was shown at the Frankfurt motorshow. Not only was the car a drop top, but it also featured four-wheel drive. In late 1982 (débuting as the 1983 model) the first 911 cabriolet went on sale (the first Porsche cabriolet since the 356). To many, this was a much more attractive car than the Targa, the other open-top 911. But while the Targa was priced to match the regular car, the Cabriolet cost significantly more. Cabriolet versions of the 911 have been offered ever since.In 1979 Porsche made plans to replace the 911 with the 928, but the 911 still sold so much better than the 928, that Porsche revised its strategy and inject new life into the Type 911 European editions. Those cars (1981-1983 911 SCs) were massaged to yield 204 bhp @ 5900 rpm from their 2994 cc powerplants. North America would have to wait for the replacement 3.2 L 911 Carrera in 1984 before seeing any extra horsepower. 911 3.2 Carrera (1984-1989) In 1984, the 3.0 L SC model was replaced by a new 3.2 L car badged "911 Carrera" but also known as the "3.2 Carrera". This version of the 911, the first to receive the Carrera label since the 2.7 RS derivative, had a 0–100 km/h (62 mph) time of 4.3 seconds (equal to the turbo) and a top speed of 152 mph, (only 6 mph less than the benchmark turbo machine). Power was increased to 207 bhp (later 217 bhp) (154 and 162 kW) for models in the United States and to 231 bhp (172 kW) for the rest of the world. The brake discs were improved to allow them to cool more quickly and, in addition, driving refinement and motor reliability were improved with an upgrade of the fuel and ignition control components to a DME (Digital Motor Electronics) system. In fact this particular marque of this vehicle was and is still arguably the one to have.The non-Turbo models became available as "Turbo-look" or "Super Sport" in 1984, a style that resembled the Turbo with wide wheel arches and the "whale-tail", it also featured the stiffer turbo suspension and the four piston aluminium brembo calipers with the bigger, drilled and vented, disks found on the turbo models and developed from the Porsche 917 brakes. The Super Sport also had the wider turbo wheels. In 1987, the Carrera got a new five-speed gearbox sourced from Getrag, model number G50. This included a hydraulic clutch.The 911 Speedster, a low-roof version of the Cabriolet which was evocative of the Porsche 356 Speedster of the 1950s, was produced in limited numbers. The 1987 Carrera Club Sport, of which 340 were produced, is a collectible 911 that had a blueprinted engine with a higher rev limit, and had the electric windows, electric seats, and radio deleted to save a claimed 50 kg in weight. 964 Series (1989-1993) In late 1989, the 911 underwent a major evolution with the introduction of the Type 964.Based with many innovation technologies from the 959 model, this would be a very important car for Porsche, since the world economy was undergoing recession and the company could not rely on its image alone. It was launched as the Carrera 4, the "4" indicating four-wheel-drive, a decision that surprised many but demonstrated the company's commitment to engineering by reminding buyers that race and rally engineering (of the 959) does affect road cars. Drag coefficient was down to 0.32. A rear spoiler deployed at high speed, preserving the purity of line when the vehicle was at rest. The chassis was redesigned overall. Coil springs, ABS brakes and power steering made their debut. The engine was increased in size to 3600 cc and developed 250 PS (184 kW). The car was more refined, but thought by some journalists to have lost some purity of the 911's concept. The rear-wheel-drive version, the Carrera 2, arrived a year later.The 964 incarnation of the 911 Turbo returned in 1990 after an absence from the price lists. Using a refined 3.3 L engine of the previous Turbo, but two years later a turbo engine based on the 3.6 L engine of the other models was introduced.In 1989, Porsche introduced the ahead-of-its-time Tiptronic automatic transmission in the 964 Carrera 2, featuring adaptive electronic management and full manual control. The 964 was one of the first cars in the world offered with dual airbags standard (from 1991), the first being the Porsche 944 turbo (from 1987).In 1992, Porsche re-introduced a limited-edition RS model, inspired by the 1973 Carrera RS and emissions-legal in Europe only. Appeals from American customers resulted in Porsche developing the RS America of which 701 were built. However, while European RS was a homologation special, RS America was an option delete variant of the regular model. The RS 3.8 of 1993 had Turbo-style bodywork, a larger fixed whale tail in place of the movable rear spoiler, and a 300 PS (221 kW) 3746 cc engine.Since the RS/RS America was intended as a no-frills, higher performance version of the 964, there were only 4 factory options available: a limited-slip differential, AM/FM cassette stereo, air conditioning, and a sunroof. The interior was more basic than a standard 911 as well; for example the interior door panels lacked the armrests and door pockets and had a simple pull strap for the opening mechanism. Although RS America was about $10,000 cheaper than a fully-equipped C2 at the time of their production, these models now command a premium price on the used market over a standard 964 (RS Europe was about $20,000 more expensive than a C2).964 Turbo (1990-1993)In 1990 Porsche introduced a Turbo version of the 964 series. This car is sometimes mistakenly called 965 (this type number actually referred to a stillborn project that would have been a hi-tech turbocharged car in the vein of the 959). For the 1991 and 1992 model years, Porsche produced the 964 Turbo with the 930's proven 3.3 L engine, improved to produce 320 PS (235 kW). 1993 brought the Carrera 2/4's 3.6 L engine, now in turbo-charged form and sending a staggering 360 PS (265 kW) to the rear wheels. With the 993 on the way, this car was produced through 1994 and remains rather rare. 993 Series (1993-1998) The 911 was again revised in 1993 and was now known as the Type 993. This car was significant as it was the final incarnation of the air-cooled 911, introduced in 1964.The exterior featured an all new front and rear end, with only the windscreen, side windows and doors maintained from the previous 964. The revised bodywork was smoother, having a noticeably more aerodynamic front end somewhat reminiscent of the 959. Styling was by Englishman Tony Hatter under the supervision of design chief Harm Lagaay.Along with the revised bodywork, mechanically the 993 also featured an all-new multilink rear suspension that improved the car's ride and handling. This rear suspension was largely derived from the stillborn Porsche 989's rear multilink design, and served to rectify the problems with earlier models' tendency to oversteer if the throttle or brakes were applied while in mid-corner.The new suspension, along with chassis refinements, enabled the car to keep up dynamically with the competition. Engine capacity remained at 3.6 L, but power rose to 272 PS (200 kW) thanks to better engine management and exhaust design, and beginning with model year 1996 to 286 PS (210 kW). The 993 was the first Porsche to debut variable-length intake runners with the "Varioram" system on 1996 models. This addressed the inherent compromise between high-RPM power production and low-RPM torque production, and was one of the first of its kind to be employed on production vehicles. A new four-wheel-drive made a return as an option in the form of the Carrera 4, the rear wheel drive versions simply being called Carrera. A lightweight RS version saw capacity rise to 3.8 L, with power reaching 300 PS (221 kW). The RS version had rear-wheel drive only.Non-turbo models appeared that used the Turbo's wide bodyshell and some other components (the Carrera 4S and later the Carrera S).The rare Targa open-topped model also made a return, this time with a large glass roof that slid under the rear window. The highly prized air-cooled 993 Targa had a limited release between 1996-1998.993 Turbo (1995-1998)A Turbo version of the 993 was launched in 1995 and became the first standard production Porsche with twin exhaust turbochargers and the first 911 Turbo to be equipped with permanent all-wheel-drive (in order to delete the 4WD, one had to refer to the more powerful and race homologated GT2). The similarity in specification and in performance levels inspired several comparison road tests with the Porsche 959 (f.e. Car and Driver, July 1997, p. 63). The 3.6 liter twin turbo M64/60 engine produced 408 hp (DIN). Water-Cooled Engines (1998-Present) 996 Series (1998-2004) After 34 years in production the famous air-cooled 911 was replaced by an all-new water-cooled model. Known as the Type 996 this car was a major leap for Porsche, although many of the traits that made the 911 what it was during the past 34 years still remained with the new model. As with the 993 before it the 996 was also a significant model, but mainly for the way it was conceived and designed, and the effect it had on Porsche during the 1990s.Pundits criticized the 996's styling a great deal, largely because it shared its headlamps—indeed much of its front end, mechanically—with the less expensive Boxster. The 996 had been on the drawing board first and was a more advanced car in some respects, but the cost-cutting seemed inappropriate for an expensive car. Otherwise, the Pinky Lai-penned shape followed the original Butzi Porsche design very closely. The interior was further criticized for its plainness and its lack of relationship to prior 911 interiors, although this came largely from owners of older 911s.The Type 996 spawned over a dozen variations, including all wheel drive Carrera 4 and Carrera 4S (which had a 'Turbo look') models, the club racing-oriented GT3, and the forced-induction 996 Turbo and GT2. The Turbo, four-wheel-drive and twin-turbo, often made appearances in magazines' lists of the best cars on sale.996 GT3 RSThe Carrera and Carrera 4 underwent revisions for model year 2002, receiving the front headlight/indicator lights which were first seen on the Turbo version two years earlier. This allowed the 911 to be more distinguishable from the Boxster. A mildly revised front fascia was also introduced, though the basic architecture remained.Engine wise, displacement was 3.4L and power 300 PS (221 kW), increased in 2002 to 3.6L and 320 f vPS (235 kW).996 GT3 (1999-2004)Porsche unveiled a road-going GT3 version of the 996 series which was derived from the racing GT3. Simply called GT3, the car featured lightweight materials inside and out, including thinner windows, the GT3 was a lighter and more focused 911 with the emphasis on handling and performance. The suspension was lower and more aggressive than other 996s, leading to excellent handling and razor-sharp steering though the ride was very firm. Of more significance was the engine used in the GT3. Instead of using a version of the water-cooled units found in other 996s, the naturally-aspirated engine was derived from the Porsche 911 GT1-98 sports-prototype racing car and featured lightweight materials which enabled the engine to rev highly.996 Turbo (2000-2004)In 2000, Porsche launched the Turbo version of the Type 996. Like the GT3, the new Turbo engine derived from the 911 GT1 engine and, like its predecessor, featured twin-turbos and now developed 420 PS (309 kW). Also like its predecessor the new Turbo was only available with all wheel drive. A 17,000 USD factory option, the X50 package, was available that boosted the engine output to a tidy 450 PS with 620 Nm (457 lb/ft) of torque across a wide section of the power band. With the X50 package in place the car could make 0-100 km/h (0-62 mph) in 4.1 seconds. This package is named as Turbo S in Europe.Styling-wise, the car was more individual than previous Turbos. Along with the traditional wider rear wings, the 996 Turbo had different front lights and bumpers when compared to the Carrera and Carrera 4. The rear bumper had air vents that were reminiscent of those on the Porsche 959 and there were large vents on the front bumper, which have been copied on the Carrera 4S and Cayenne Turbo. 997 Series (2005-Present) In 2004 the 911 was heavily revised and the 996's replacement, the 997, was unveiled in July. The 997 keeps the basic profile of the 996, bringing the drag coefficient down to 0.28, but draws on the 993 for detailing. In addition, the new front fascia is reminiscent of the older generation, with the traditional "bug eye" headlamps. Its interior is also similarly revised, with strong links to the earlier 911 interiors while at the same time looking fresh and modern. The 997 shares less than a third of its parts with the outgoing 996, but is still technically very similar to it. Initially, two versions of the 997 were introduced - the rear wheel drive (2wd) Carrera and Carrera S. While the base 997 Carrera produced 325hp from it's 3.6 liter Flat 6, a more powerful 3.8 liter 355hp Flat 6 powers the Carerra S. Besides a more powerful engine, the Carrera S also comes standard with 19" "Lobster Fork" style wheels, more powerful and larger brakes (with red calipers), a more sporty suspension, complete with PASM (Porsche Active Suspension Management) which allows for electronic adjustability of suspension settings, Xenon Headlamps, and Sport Steering wheel. In late 2005, Porsche announced the all wheel drive versions to the 997 lineup. Carrera 4 models (both Carrera 4 and Carrera 4S) were announced as 2006 models. Both Carrera 4 models are wider than their rear wheel drive counterparts by 1.26" to cover wider rear tires. 0-60mph for a base Carrera 4 with the 325hp engine was reported at 4.5 seconds according to Edmunds.com. The 0–100 km/h acceleration for the Carrera S with the 355hp was noted to be as fast as 4.2 seconds in a recent Motor Trend comparison, and Road & Track has timed it at 3.8 seconds. Type 997 versions of the GT2 and Turbo S have yet to have a released introduction date. The 997 lineup includes both 2 and 4 wheel drive variants, Carrera 2 and Carrera 4 respectively. The Targas (4 and 4S), released in November 2006, are 4-wheel drive versions that divide the difference between the coupes and the cabriolets with their dual, sliding glass tops. There were rumours that the 997 911 was to undergo an update for the 2008 model year, however it appears these changes may be held off until the 2009 model year (or possibly 2008.5). The main changes will be a larger air intake in the front bumper, new headlights, new rear lights, engines with direct fuel injection, and the introduction of a dual-clutch gearbox.997 TurboThe Turbo version of the 997 series featured the same 3.6 L twin-turbocharged engine as the 996 Turbo, but this time it developed 480 HP (353 kW) and 620 N·m (457 lbf·ft) of torque. This was in part due to the 997's new variable-geometry turbocharger, which essentially combines the low-rev boost and quick responses of a small turbocharger with the high-rev power of a larger turbocharger. As well as producing more power and flexibility, the new turbocharger improved fuel consumption over the 996 Turbo. With these performance upgrades, it accelerates to 100 km/h (62mph) in 3.9 seconds (3.7 with the Tiptronic transmission) and reaches a top speed of 310 km/h (193 mph). However, these are official figures and Porsche is notable for being conservative about their power and performance ratings. Motor Trend Magazine has clocked the 997 Turbo's 0-60MPH time in 3.2 seconds with the Tiptronic S transmission. The optional Sports Chrono overboost package increases torque to 680 N·m (505 lbf.ft) for short periods (maximum 10 seconds) but over a narrower rev range.The 997 Turbo features a new all wheel drive system, similar to the one found on the Porsche Cayenne. Featuring PTM (Porsche Traction Management) the new system incorporates a clutch-based system which varies the amount of torque to the front wheels, regardless of wheel slip front and rear. This, according to Porsche, aids traction and the handling by redirecting the torque to control oversteer or understeer, thus resulting in far more neutral handling, as well as greatly improved performance in all weather conditions (as opposed to older AWD system which gave the Turbo stability under hard acceleration).Styling wise, as with the 996 Turbo the car featured more unique styling cues over the Carreras, one of the more distinctive elements the front LED driving/parking/indicator lights mounted on a horizontal bar across the air intakes. The traditional rear wing is a variation of the 996 bi-plane unit.997 GT3The 911 GT3, announced on February 24, 2006 is reported to accelerate 0-100 km/h in 4.3 seconds and have a top speed of 310 km/h (193 mph), almost as quick as the Turbo. Porsche's factory reports can be conservative though; Excellence magazine tested the 997 GT3 and recorded 0-100 km/h in 3.9 seconds and a top speed of 312 km/h (194 mph). The 997 GT3 was released in the summer of 2006. It was recently crowned "the best handling car" by Motor Trend.997 GT2The GT2 variant of the 997 has been spotted in testing around the Nürburgring. The car shares much of its bodywork with the Turbo but has a different rear spoiler and extra venting for the radiator. While no official specifications have been released, Car and Driver speculates that the car will have around 525 hp, 51hp more than the Turbo (based on the fact that the 996 GT2 also had 51 hp more than the equivalent Turbo).