Guide: Nissan Fairlady 240ZG (HS30-H)
Background
For the 1971 racing season, the FIA revised their existing competition class framework. In terms of production-based machinery of the type available in new car showrooms, manufacturers could contest Groups 1 through 4.
Groups 1 and 2 were for Touring Cars. They required a minimum production run of 1000 and 500 units within a twelve month timeframe respectively. Cars competing in Group 1 were more or less permitted to only run additional safety gear while those in Group 2 could also benefit from engine tuning, wider wheels and tyres, improved aero and an array of other modified parts.
Groups 3 and 4 were for Grand Touring vehicles. As per Groups 1 and 2, 1000 and 500 car runs were required to gain homologation with Group 3 having effectively been for standard machinery (as per Group 1) while Group 4 permitted a similar package of upgrades as Group 2.
Upon its introduction in late 1969, Nissan had initially offered Japanese customers their handsome new Z car in two-litre Fairlday trim while export markets got the 2.4-litre 240Z.
During 1970, the firm contested a series of high profile races on home soil with the two-litre Fairlady Z432-R which ran a trick motor with four valves per cylinder, triple carbs and dual overhead camshafts.
For the 1971 season (when the new regulations came into effect), Nissan famously campaigned the bigger-engined 240Z in Group 3 rally trim and most notably won that year’s East African Safari Rally.
For 1972, Nissan wanted to go circuit racing with a Group 4 version of the 240Z which, since November 1971, had also been offered in Japan alongside the two-litre variant following lots of requests from customers.
Three versions of the 240Z were supplied in Japan for the 1972 model year: the standard HS30-S (the 240Z), the slightly more luxuriously equipped HS30 (also known as the 240Z-L) and a Group 4 homologation special dubbed the HS30-H (better known as the 240ZG).
Although the 240ZG was only supplied as a complete car to the Japanese market, it was also offered in kit form to US buyers as required by local competition regulations. The car’s G moniker stood for Grande and the upgrade pack was often referred to as the G-nose across the Pacific.
In addition to an extended air-piercing front end, the ZG most notably came with riveted over fenders to permit the use of much wider wheels in Group 4 race trim, a trunklid-mounted spoiler and a limited-slip differential.
Production began in October 1971.
Bodywork
By far the ZG’s most striking feature was its extended ‘aero-dyna’ nosecone which added 190mm to the existing car’s overall length.
Fashioned from lightweight fibreglass, the G-nose sloped downwards to give a much more aerodynamic profile along with some extra downforce which enabled the Group 4 racing variant to reach much higher speeds. It also came with a more neatly integrated one-piece wraparound bumper and a re-profiled apron complete with wide central radiator intake and flush-mounted indicators.
To further improve airflow, clear Plexiglas covers complete with chrome-plated bezels were fitted over the noticeably longer headlights bowls.
Down each flank, riveted wheelarch extensions were similarly manufactured from fibreglass and added 60mm to the ZG’s overall width.
Mounted on the trunklid was a large full width rear spoiler designed to equalise the additional downforce created from the more aggressively profiled nosecone.
As per other JDM variants of the Fairlady / 240Z, streamlined rear view mirrors were mounted well forward on the front fenders and left in an unpainted satin black finish.
Customers could choose from on of three colours (Grande Prix Red, Grande Prix White and Grande Prix Maroon). The front bumper, front apron, wheelarch extensions and rear spoiler were given a contrasting satin grey finish.
Chassis
Each Z car was based around a pressed steel monocoque equipped with fully independent suspension.
The front end comprised MacPherson struts with lower transverse links, drag links and an anti-roll bar. At the rear were Chapman struts and lower wishbones. Coil springs and telescopic dampers were fitted all round.
Braking was courtesy of discs up front and drums out back.
As per the rest of the 1972 model year range (introduced from October 1971), the ZG ran 14 x 5-inch steel wheels with hub caps that featured soft triangular openings and a central Z emblem.
A 60-litre fuel tank was installed underneath the rear storage compartment.
Engine / Gearbox
In the engine bay was Nissan’s highly rated single overhead camshaft straight six. It featured a cast-iron block and an aluminium alloy head with two valves per cylinder.
The 240Z used Nissan’s L24 engine which had a capacity of 2393cc. Compared to the two-litre L20 unit, bore was increased from 78mm to 83mm and the stroke was extended from 69.7mm to 73.7mm.
Compression and fuel feed were identical to the L20 (9.0:1 with two SU-type Hitachi HJG 46W sidedraught carburettors).
Peak output was 151bhp at 5600rpm and 146lb-ft at 4400rpm.
As per all JDM Z cars, a five-speed gearbox was fitted whereas 240Zs destined for North America came with a four-speed unit.
A key feature of the ZG was its limited-slip differential fitted as standard.
Interior
Inside, a wood-rimmed three-spoke steering wheel fronted two primary cowls that were home to a rev counter and speedometer.
Three smaller cowls were mounted above the centre of the dash. These housed a clock and combined gauges for battery amps / fuel and oil temperature / water temperature.
The central console directly below contained the ventilation controls and a radio.
Vinyl leatherette was used to upholster the seats, side panels and gear gaiter with carpet pretty much everywhere else. To save weight, the ZG came with thinner carpet and reduced sound insulation.
The large rear hatch was supported by two gas-filled struts. Once opened it provided a generous amount of luggage space. Two straps helped secure any load in place.
Options
For those customers that wanted to go racing, all manner of engine tuning options were available along with wider 7, 8 and 10-inch magnesium wheels and a long-range 100-litre fuel tank.
Weight / Performance
Compared to a standard JDM 240Z which weighed in at 1040kg, the ZG tipped the scales at 30kg less (1010kg).
Top speed was 5mph higher as a consequence of the improved aerodynamics (now 130mph). 0-62mph took two-tenths of a second less (7.8 seconds).
End of Production
Nissan produced the 240ZG for just a few months between 1971 and ‘72. Precisely how many were constructed is unclear, however, its is unlikely to be vastly more than the 500 units required for Group 4 homologation.
Factory built cars were produced exclusively in right-hand drive.
Highway Police Version
In 1972, Nissan supplied a 240ZG to the police department of Kanagawa Prefecture, mainly for use as a high speed pursuit car. It was equipped with a variety of additional radio equipment, extra lighting and a handsome white over black colour scheme.
Prior to its return to Nissan, the car racked up over 370,000km. It is now part of the company’s heritage collection.
Competition History
With its even wider fender extensions, deep chin spoiler and bigger rear spoiler, the 2870cc 300bhp LY28-engined GTS-II competition version of the ZG proved an extremely effective competition car, most notably winning the 1972 Fuji Grand Champion series and 1973 Suzuka 1000km.
Text copyright: Supercar Nostalgia
Photo copyright: Nissan - https://www.nissan-global.com
