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.

[6] After the size and configuration of 80 mm (3.15 in) bore x 66 mm (2.60 in) stroke, 1,991 cc Typ 901 engine with Solex 40PI carburettors[c] 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.

These earliest editions of the 911 had Typ 901/01 an air-cooled, rear-mounted, all-Aluminium-alloy, 2.0 L (1,991 cc) 130 PS (96 kW) 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.

165R15 Pirelli Cinturato tyres were fitted to 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.

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.

Porsche feared the U.S. National Highway Traffic Safety Administration (NHTSA) would outlaw fully open convertibles,[citation needed] an important market for the 356.

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 T effectively replaced the 912, while the staple 130 PS (96 kW) 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).

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 210 PS (154 kW), with 810kg weight, had a very limited production of just 20 cars in 1967.

The unique magnesium-alloy crankcase (in MY1969), fibreglass fuel tank (in MY1973), and hydraulic cam chain tensioners (in MY1984) became standard equipment on all 911s in slightly different formats years later.

The body had aluminium engine lid, and hidden-from-sight pull levers on door handles, replacing the previous push buttons.

Porsche factory team used 911E in rally events, where a wide power band is more advantageous, and the 911E was called the "Secret weapon from Zuffenhausen" by the amateur entrants who tended to buy the 911S given the choice.

Another significance of the 915 transmission is the differential gear axis line being closer to the engine to remedy the driveshafts having a rearward angle to accommodate the 57mm increase in wheelbase on the B, C, and D series.

Due to the 911's unusual engine placement (rear-mounted, with a large percentage of the vehicle's weight concentrated over the rear axle), early 911s were prone to oversteer when driven at the limit.

Because the STs were produced to order for racing purposes, no two 911 ST were the same; some used thinner gauge steel body panels and some used aluminum or fiberglass; some did not have the mismatched tyres, or used different sizes depending on the circuit and availability.

The RS was built so that Porsche could enter FIA Group 4 GT class in racing that required minimum 500 unit production volume.

The RSR Turbo came in second overall at the 24 Hours of Le Mans in 1974, a significant event in that its engine would form the basis of many future Porsche attempts in sports car racing, and can be regarded as the start of its commitment to turbocharging.

[citation needed] This emerged in 1975 in California where thermal reactors, aimed at reducing emissions, were fitted below the cylinder heads thus causing heat build up around the magnesium crankcase and then made worse by the lean running K-Jetronic CIS.

Bearing in mind Porsche's largest market being the US, the 930 Turbo, Carrera 3.0 and all subsequent models used aluminium alloy crankcases which were around 15 lb (7 kg) heavier.

As demand for the Turbo soared in the late 1980s, Porsche introduced novelty variants including a slant-nose version (option M505/M506), while not significantly improving the range mechanically.

Designated M439, it was offered in two colors with the turbo whale tail & front chin spoiler, body color-matched Fuchs [de] alloy wheels and other convenience features as standard.

The 911 3.2 Carrera was the second iteration of the 911 series, with all subsequent models featuring new body styling with new brake, electronic and suspension technologies.

The disc brakes were increased in size to aid in more effective heat dissipation and improved oil-fed chain tensioners were fitted to the engine.

Changes in the fuel map & chip programming from October 1986, further improved the power to 217 hp (162 kW; 220 PS) at 5,900 rpm for North American delivered cars as well as for other markets requesting low emissions, like Germany.

Very modest cosmetic changes were made throughout the lifespan of the Carrera, with a redesigned dash featuring larger air conditioning vents appearing in 1986.

[25] It started as a design under Helmuth Bott [de] in 1983 but was not manufactured until six years later, championed by Porsche's president, the German-American Peter Schutz.

It was a two-seat convertible that featured a low swept windshield and a pair of controversial 'camel hump' cowlings behind the seats that concealed the stowed-away manual hood.

In 1987, Porsche decided to produce 340 units for their customers that wanted a track inspired road car, the Club Sport lost around 50 kg (110 lb) in weight by ditching non-essential equipment such as the radio, sunroof, A/C and the rear seats.

Larger and featuring a front-mounted V8 engine considerably more powerful than the contemporary 911's flat six, the 928 was intended to be a comfortable grand tourer rather than a dedicated sports car.

In spite of its overall capability, the expensive company flagship never outsold the 911, and unlike its smaller, sportier sibling, and, as a large, heavy, front-engined grand tourer, achieved little success in racing.