Carrera 2.7 / G and H series (1974-1975)
MY 1974 saw three significant changes. First, the engine size was increased to 2687 cc giving an 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 two of the three models in the 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 (110 and 129 kW) respectively.
The Carrera 2.7, now a regular production model, inherited the wider rear wings of the RS together with its 210 PS (154 kW) MFI engine and was indeed mechanically identical to the 1973 RS and still weighed the same at 1075 kg (2370 lb). All three 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 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 lb (7 kg) 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 190–175 PS (140–128 kW) despite the displacement increase from 2.4–2.7 L. However, the engine did have increased drivability. The 210 PS (154 kW) 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 (173 hp/129 kW), later reduced to 165 (121 kW), and in California even down to 160 PS (118 kW).
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-series chassis and the 2.0 Volkswagen engine from the Porsche 914. In all, 2099 units were produced. 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 928
Although 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 real 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 could never outsell the 911. Notably, it achieved little success in racing.
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