The original Porsche 911 (pronounced nine eleven, ) is a sports car made by Porsche AG of Stuttgart, Germany. A prototype of the design was shown to the public in autumn 1963. Production began in September 1964 and continued through 1989. It was succeeded by a modified version, internally referred to as Porsche 964 but still sold as Porsche 911, as are current models.

Mechanically, the 911 was notable for being rear engined and air-cooled. From its inception, the 911 was modified both by private teams and the factory itself for racing, rallying and other types of automotive competition. The original 911 series is often cited as the most successful competition car ever, especially when its variations are included, mainly the powerful 911-derived 935 which won 24 Hours of Le Mans and other major sports cars races outright against prototypes.

Prototyping

To update the style and utility of the 356B's T5 body, T7 body styling/design project was led by Butzi Porsche by applying modified style and 100mm longer wheelbase to 356B Karmann hardtop in 1959–1960. Another design/engineering project, T6 body, led by Erwin Komenda, including a bigger front trunk and rear engine compartment opening, bigger rear window, and twin grilles on the engine lid, was progressing alongside. The T6 debuted in 1962 as a facelift on 356B without the longer wheelbase or the 911-like front and rear style of the T7.

The increase in body length was used on the T7 prototype for the rear '+2' passenger room making the body a full(er) four-seater, not for additional space for a six cylinder engine as it, as well as the T6, was a 356 body style candidate. The T7 body was completed into a drivable prototype with a pushrod 1600 Super (1582cc 75hp Typ 616/12) engine as Typ 695. In 1962–63, the 695's engine was swapped with 2L four cylinder DOHC engine of 356B Carrera GS (1968cc 130hp Typ 587/1) and became Typ 754, that served as a benchmark in comparisons against Typ 901 prototypes.

Klaus von Rücker and Leopold Jäntschke led the team, including a young Hans Mezger and Ferdinand Piëch, to develop the 2 litre six cylinder engine that was numbered the Typ 745 with intake camshaft above, and exhaust camshaft below the crankshaft to operate horizontal pushrods in an unusual dry-sump configuration. Ferry Porsche, having experiences on DOHC racing engines, did not like this arrangement in the air-cooled six cylinder pushrod engine as it did not have sufficient benefit to justify the increase in the number of camshafts. Also, the new twin vertical (horizontal axis) fans on this were found to suffice with only one vertical fan in the development, as this cast-aluminium 11-wing-blade design utilising a 12V AC alternator as the drive shaft (developed on racing engines with then-new fibre-glass shroud) was much more efficient than the Volkswagen-style flat-plate fabricated fin scirocco fan (in front of a DC generator) of Typ 502/506/508/527/528/531/532/546/557/589/616 engines for the 356.

So the 745 engine was abandoned and the 2 litre air-cooled SOHC (two camshafts on a flat six engine) 'wet-sump' six cylinder boxer Typ 821 engine was drafted and prototyped with a single vertical fan. Although wet-sump was the norm for Porsche production engines, Ferdinand Piëch strongly argued for dry-sump of the 745 that could give a lower center of gravity through lower position of the engine/crankshaft in the car as well as a straight adaptability to racing. Ferry Porsche agreed with this Piëch opinion and the dry-sump Typ 901 engine was born with a single intermediary shaft below the crankshaft (which also drives the oil scavenge and pressure pumps mounted inside the crankcase) that drives two single-stage single-row chains, in turn, driving a camshaft in each of the two cam-carriers on six cylinder-heads.

After the size and configuration of bore x stroke, 1,991 cc Typ 901 engine with Solex 40PI carburettors were more or less finalised, Butzi Porsche led a team to merge the front and rear style of the T7 body with the size requirements of the six cylinder dry-sump engine, as well as other new components including Typ 901 four/five-speed transaxle, rack and pinion steering, MacPherson strut front suspension, and semi-trailing arm rear suspension to come up with the T8 body. Erwin Komenda was responsible in the chassis design to incorporate the new components. The resultant Typ 901 chassis/body ended up being 70mm narrower and 120mm longer than the production T5/T6 body of the 356B/C, with a 111mm longer wheelbase.

This car was introduced to the world as "Porsche 901" at the 1963 Internationale Automobil-Ausstellung (Frankfurt Motor Show) on 12 September 1963. However, Peugeot protested because it had exclusive rights in France to car names formed by three numbers with a zero in the middle. Instead of selling the new model with a different name in France, Porsche changed the model name to "911" for all markets, but the engine designation and parts number prefix remained '901'. A total of 82 cars (The factory retained chassis #01, 02 and 03. Chassis number 13 was skipped and became #14.) were built as model "901" before the production switched over to the "911" marking on the engine lid, and it went on sale as "Porsche 911" in 1964.

2.0-litre / O, A and B series (1964–1969)

The initial series became known as the O series, produced until July 1967, and the MY1968 911s as the A series, followed by the MY1969 B series. These earliest editions of the 911 had Typ 901/01 an air-cooled, rear-mounted, all-aluminium-alloy, SOHC flat-six boxer engine, which has almost no parts interchangeability to the 356's four-cylinder pushrod 1.6L, or the 2.0L DOHC unit. It was mated to a five-speed manual "Type 901" transmission. The car had 2+2 seating, though the rear was very small, like the 356. The styling was by Ferdinand "Butzi" Porsche, son of Ferdinand "Ferry" Porsche. Erwin Komenda, the leader of the Porsche car body construction department, was responsible for the engineering aspects of the new chassis/body, incorporating the new engine, transmission, steering, and suspension into the monocoque.

In mid-1966, the 901/01 engine (9.0:1 compression ratio, Solex 40PI) was changed to Typ 901/05 with two Weber 40IDA3C carburettors (3 choke/barrel, with two fuel needle valves and two floats each). For the model year (MY)1967, Porsche introduced the more powerful 911S (901/02 at 6,600 rpm, 9.8:1 compression ratio, Weber 40IDA3C carburettor). Forged 911R-style alloy wheels from Fuchs, in a distinctive 5-leaf design, were offered for the first time, which coincided with the 911S debut. In 1967, racing version Typ 901/20 (Weber 46IDA3C) twin-plug engine was developed and used in the Porsche 904/6, 911R, and 906 (Carrera 6) racing models.

A semi-automatic (clutchless manual) Sportomatic model, composed of a torque converter, electrically-switched and pneumatically operated clutch, and a conventional four-speed manual transmission, was added to 911L (901/04, Weber 40IDA3C) as an option for MY1967.

The 911L was also fitted with the ventilated brake discs from the S model and was the top version available in North America (901/14 for manual, 901/17 for Sportomatic in Canada/US), where the 911S could not meet emission requirements.

The Targa version, with a stainless steel-clad roll bar, appeared also for MY1967. Porsche feared the U.S. National Highway Traffic Safety Administration (NHTSA) would outlaw fully open convertibles, an important market for the 356. It was equipped with a removable roof panel and a removable plastic rear window (a fixed glass version was offered alongside from MY1968). The name "Targa" – plate or plaque in Italian – came from the Targa Florio road race in Sicily, in which Porsche had scored seven victories since 1956, with four more to come through 1973. This last in the subsequently discontinued event is especially notable as it was won with a production 911 Carrera RS (F series) against prototypes entered by Italian factories of Ferrari and Alfa Romeo.

The 911T, for "Touring", was launched in October 1967 with Typ 901/03 engine (Weber 40IDA3C), the only engine in the history of 911 without counter-weights on the crankshaft. The T effectively replaced the 912, while the staple model was made slightly more upscale and renamed the 911L (for "Luxus", with Weber 40IDA3C, ventilated disc brakes, and heated rear window glass; 901/06 engine for manual, 901/04 for Sportomatic).

In MY1968, 911T switched over to 901/13 (Weber 40IDT3C, with counter-weights, for the manual), while 911S and 911T became available with Sportomatic (901/08 160hp at 6,600 rpm with Weber 40IDS3C for 911S, and 901/12, Weber 40IDT3C, with counter-weights and 110hp for 911T). 911L engine switched from 901/04 to Typ 901/07 for Sportomatic (with the same Weber 40IDA3C and ) at the same time.

For MY1969, the new B series was introduced, which moved the rear wheels on all 911 models 57 mm aft, increasing wheelbase from without lengthening the body, to remedy the car's oversteer tendencies at the limit. Also for MY1969, Kugelfischer/Bosch mechanical fuel injection (MFI) with a plunger-type fuel pump/distributor driven by the left camshaft via a toothed belt, 6 fuel injectors, and 6 throttle butterflies, arrived both for the 911S (901/10, ), and a new middle model, the 911E (901/09 for manual and 901/11 for Sportomatic, both with ), which replaced the short-lived 911L.

912 (1965–1968)

When 356 production came to an end in 1965, there was still a market for a four-cylinder car, particularly in the USA where the largest bulk of Porsches were sold. Porsche 902, a slightly downscaled 901 fitted with three-dial gauge cluster (911-style 5 dial as an option), a detuned version (Typ 616/36 engine, ) of the four-cylinder 356SC pushrod engine (Typ 616/16 ), mated with four-speed Typ 901 transmission (with a five-speed as an option), and with silver-colour (as opposed to 911's gold-colour) 'PORSCHE' and '912' letterings on the engine lid, was introduced as Porsche 912 soon after the 911 for MY1965. In 1965, production averaged about 30 912s and 20 911s a day. The 912 was replaced by the 911T in 1968.

911R (1967) The 911R, a lightweight racing version with thin aluminium doors, plastic door handles, smaller front and rear indicator lights, spartan interior with a bucket seat and a smaller-diameter steering wheel, magnesium-alloy crankcase, twin-spark cylinder heads, and a power output of , with 810kg weight, had a very limited production of just 20 cars in 1967. The production volume did not meet the FIA GT class production car requirement, so it competed against purpose-built prototype class racing machines. The forged 6" x 15" wheels made by Fuchs as a racing part for 911R became optional equipment for production 911s. Weber 46IDA3C carburettor and twin ignition with a 12-terminal distributor on this SOHC 2-valve racing engine (Typ 901/20, without a heat exchanger or heater ducts, with centrifugal advance in place of a vacuum advance on the distributor), along with fibreglass fuel tank, were passed on to later racing models including Porsche 906. The unique magnesium-alloy crankcase (in MY1969) and hydraulic cam chain tensioners (in MY1984) became standard equipment on all 911s in slightly different formats years later.

911S/R (1967–1968), 911T/R (1968) In order to compete in the "Group 3 GT" production based class, Porsche offered the "Rally Kit" for the 911S, and later for the 911T, in order to take advantage of the 911T lower homologated weight. They were built in low quantities to a range of specifications depending on their intended competition purposes. These cars are frequently referred to as 911S/R and 911T/R, but because they use the standard 911S and 911T as the homologation models, they are usually listed in official racing documentation as "911S" and "911T".

B17 (1969)