The capacity went from 2195cc to 2341cc, along with gains in power, especially for models exported to the North American market. The American market also gained a mechanical fuel injection system, replacing the traditional Weber carburetors.
The change in engine capacity was achieved by increasing the stroke, which in turn allowed Porsche to reduce the compression ratio, thus optimising combustion efficiency. In addition to these changes, the engine was reinforced with a forged crankshaft to allow for the additional loads of the 911 Turbo version.
In the constant search for improvement in 1972, Porsche made the effort to alleviate the 911’s brand-damaging pendulum effect caused by the rear engine philosophy—by relocating the engine oil tank. Though this position was reversed on the 1973 models because customers very often confused the oil filler cap with the fuel cap.
Another of the novelties for the 1972 911 was the adoption of a new gearbox. Known internally as Type 915, the new box could be specified with four or five ratios and was derived from Porches own 908 competition model. Unlike the previous Type 901, the new gearbox had a more robust lubrication system, and it could easily be identified by its “H” pattern, next to the previous dog-leg system. For customers in North America, Porsche continued to offer the Sportomatic automatic transmission as an option.
In 1973, the 911 underwent some detailing changes, with the E model receiving the ATS 6Jx15 cookie-cutter wheels as standard. The engine specification however remained unchanged. The Type 911/52 engine, with its mechanical fuel injection, maintained its 2341cc capacity and delivered 165hp at 6200 revolutions per minute with a maximum torque of 205 Nm at 4000 revolutions per minute.
In terms of the transmission, the new 911 E could be specified with four or five manual gears and a 4-gear Sportomatic transmission. Only 1,366 F-series units of the Porsche 911 2.4 E were produced in 1973.