Guide: Porsche 911 2.4 E & F-series

Apr 2

Apr 2 Guide: Porsche 911 2.4 E & F-series

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Background

When Porsche introduced the 2.2-litre 911 in September 1969, many felt the model had reached the limit of its potential.

Rumours swirled that an entirely new replacement was on the cards; a big front engined Gran Turismo with a conventional water-cooled engine that would take the firm further upmarket.

Porsche were actively considering such a machine and gave it the green light in 1971, but the resultant 928 never matched the commercial appeal of the iconic 911.

Thankfully, development continued on the 911 and, in September 1971, Porsche unveiled their latest iteration: the 2.4-litre E-series.

These 2.4-litre derivatives were manufactured for the 1972 and 1973 model years. With their powerful, torquey engines and new Type 915 gearboxes, they widely came to be regarded as the best F-body 911s prior to the advent of the heavier impact bumper G-body introduced for the 1974 model year.

2.4-litre 911s were offered in three states of tune and two alternative body styles (Coupe and Targa). There was the entry level 911 T, the mid-range 911 E and the flagship 911 S. Each variant came with progressively more power than the last.

Chassis

For this latest application, the 911’s unitary steel bodyshell was little unchanged.

Suspension was fully independent with torsion bars and telescopic shocks. The front end used a compact MacPherson strut arrangement with a single lower wishbone while at the rear, semi-trailing arms were installed.

The wheelbase was extended by 3mm thanks to altered rear suspension mounting points (an attempt to eliminate compound movement of the strut). The change had the happy side effect of facilitating extra suspension travel which further improved ride quality.

The rear semi-trailing arms were revised to allow their removal without having to drop the engine out of the car.

Boge’s hydro-pneumatic shocks previously used on the 911 E were made optional as this variant reverted to the same suspension set up as the 911 T. The 911 S still came with Koni dampers.

The 15-inch Fuchs alloys that were standard on all 2.2-litre 911s were now optional on the 911 T and 911 E. Standard equipment for the 911 T was pressed steel 5.5-inch rims while the 911 E came with new 6-inch wide ATS cookie cutter alloys. 6-inch Fuchs forged alloys were fitted to the 911 S and, in some markets, they were an automatic upgrade for other variants as well.

Front and rear anti-roll bars were fitted as standard to the 911 S which now came with a secondary oil cooler fitted in the right-hand front fender.

Engine & Gearbox

The bigger 2.4-litre engines not only gave more power and torque, they also helped Porsche comply with increasingly stringent emissions legislation. Furthermore, the 2.4 lump enabled the use of lower compression ratios as fuel quality was dropping in lots of markets.

Thanks to a 4.4mm lengthening of the stroke (from 66mm to 70.4mm), displacement rose from 2195cc to 2341cc. Bore dimensions were unchanged at 84mm.

These engines featured new camshafts, shorter and lighter con rods, reduced height piston crowns cooled by individual oil jet sprays, improved porting, larger big ends, full crankshaft counter-balancing, a crankcase stiffened around the main bearings and a new forged crankshaft.

Specifications for the three variants were as follows:

911 T: Type 911/57, 130bhp at 5600rpm / 196lb-ft at 4000rpm, 7.5:1 compression, two Zenith 40 TIN carburettors.

911 E: Type 911/52, 165bhp at 6200rpm / 206lb-ft at 4500rpm, 8.0:1 compression, Bosch mechanical fuel-injection.

911 S: Type 911/53, 190bhp at 6500rpm / 216lb-ft at 5200rpm, 8.5:1 compression, Bosch mechanical fuel-injection.

While the 911 E and 911 S did not require any compliance modifications, 911 Ts destined for the USA, Australia, Japan and Canada used Bosch mechanical fuel-injection instead of Zenith carburettors. These Type 911/51 engines produced 140bhp at 5600rpm and 200lb-ft at 4000rpm (10bhp and 4lb-ft more than the rest of the world offering).

All 2.4-litre 911s came with a new Type 915 gearbox that afforded greater torque capacity than the outgoing 901 unit albeit at the expense of an additional 9kg.

The 915 gearbox had a conventional gate pattern instead of the old dogleg first.

It was offered with both four-speeds (911 T) and five-speeds (911 E and 911 S).

The four-speed semi-automatic Sportomatic option was still available and given a new type number (925). Engines equipped as such came with the following type numbers: 911/67 (911 T), 911/62 (911 E) and 911/63 (911 S). The fuel-injected 911 T with Sportomatic was engine type 911/61.

Bodywork

Cosmetically, E-series 911s came with a distinctive oil filler cap positioned behind the right-hand door which was opened by a button on the adjacent door pillar.

Other universal changes included a black instead of aluminium engine grille and gunmetal model script rather than anodised gold.

A bigger driver’s side wing mirror was also fitted (a passenger mirror was still an optional extra).

The 911 S now came with a new front spoiler said to reduce front-end lift by 40%. This handsome appendage was optional on the 911 E and 911 T.

Interior

Only minor alteration were made inside.

The old basket-weave dash insert was dropped in favour of plain vinyl that matched the rest of the upholstery.

Also gone was the 911 logo previously mounted on the passenger side of the dash.

Wrinkled black seat hinges replaced chrome.

The 911 S came with door sill kick plates (optional on other variants).

All US-spec. cars came fitted with inertia reel seat belts.

Aside from sharing its leather steering wheel with the 911 S, the 911 E interior was now based on the 911 T.

Options

Customers could enhance their cars by choosing from the huge numbers of optional extras available. These included sports seats, air-conditioning, full or half leather upholstery, a limited-slip differential, electric windows, fog lights, spot lights, an electric sunroof, Fuchs wheels and head rests.

A new 85-litre fuel tank with space saver tyre was offered for the first time while the 911 S could still be specified with an enormous 110-litre fuel cell.

Various radio options were offered along with a Comfort pack for the interior and an ‘S’ kit that added the front spoiler, wheels and sill plates from the 911 S to the 911 E or T.

Weight / Performance

Standard Coupes weighed 1050kg and Targas were 1100kg.

Performance figures were:

911 T: 126mph top speed and 0-62mph in 8.8 seconds.
911 E: 138mph top speed and 0-62mph in 7.8 seconds.
911 S: 144mph top speed and 0-62mph in 6.6 seconds.

End of 1972 Model Year E-series Production

Production began in August 1971 and continued for twelve months during which time just under 13,000 were built. This figure was split as follows:

911 T Coupe: 4894 / 911 T Targa: 3344
911 E Coupe: 1124 / 911 E Targa: 861
911 S Coupe: 1750 / 911 S Targa: 989

1973 Model Year F-series

Porsche’s 1973 model F-series 911s were produced from August 1972 and ushered in another round of upgrades.

The oil filler located behind the right-hand door was dropped after owners and petrol station attendants repeatedly mistook it for the fuel filler.

The horn grilles and supplementary light surrounds at either end were now finished in black instead of chrome.

A rear wiper was fitted across the range.

Airflow to the oil cooler was improved by modifying the baffles.

For the first time, Targas, were available in right-hand drive.

US-bound machinery came with black rubber overrider pads as dictated by ever-tightening American safety legislation.

In January 1973, the fuel-injected US-spec. 911 T switched to a Bosch K-Jetronic Continuous Injection System and new camshafts were fitted with reduced valve opening timing.