The Datsun 280ZX 2-seater
A weakening of the muscles
The USA, particularly the West Coast, is the World’s largest sports car market and has always had a major influence on design trends. It was for the Americans that Datsun created the impressive Z-series of fixed-head sports cars and they responded by boosting it into the World’s best selling sports car. US emission laws were hardly biting when the 240Z was announced in October 1969 and the smooth and free revving 2.4-litre, sohc, straight-six engine had enough power to make the Z a “muscle” car in the US as well as elsewhere. But as emission restrictions tightened, so Nissan-Datsun were forced to enlarge the engine to avoid total emasculation, first to 2.6-litres as the 260Z, then, for the US only, to 2.8-litres as the 280Z. The next stage, in I 978, was to re-shell the nine-year-old theme, to meet current demands of creature comforts and legislation. The result was the 280ZX, which came to the British market in 2-seater and 2 + 2 versions in March last year.
Zs for the British market have always been of straightforward, 2.4, 2.6 and now, in ZX form, 2.8-litre specification, but there have been all sorts of variations at any one time in engines and nomenclature in other markets. On its home market, the slightly differently styled, Fairlady Z has always been available with a 1,998 cc, straight-six engine and this engine continues to be available in the new body. The most interesting variation of all, available only on the Japanese domestic market, was the PS30 (Z432), which combined a lightweight body with a d.o.h.c., six-cylinder in line, 1,988 c.c., 24-valve triple carburetter engine. There was even a racing version in that series, designated the Z432R.
I have always been a fan of the muscular Zs, whose pedigree includes Safari Rally wins in 1971 and 1973, and can claim to be one of the few people in Britain to have raced one in International events, so I viewed the 280ZX with especial interest. It disappointed. The engine is so besmogged that the sparkle has gone out of it, the capacity increase has robbed it of its silky willingness to rev, and relative to its sporting image it is gutless, especially in the lower speed ranges. The lithesome lines of the old Z have been spoiled by middle-aged spread – a very Americanised body, as if the Z has eaten too many of those delectable and fattening US breakfasts (I know the feeling). Naturally, this extra metalwork has put on weight, too, 2,657 lb against the 260Z’s 2,425 lb, but the ZX is actually more aerodynamically slippery than the 260Z, with a drag coefficient of 0.385 compared with 0.467.
The extra capacity is achieved by increasing the bore sizes from 83 mm to 86 mm, compared with the 260Z; while retaining the 79 mm stroke (the 240Z was 83 mm X 73.7 mm). The actual capacity is 2,753 cc. This L28E engine, with seven main bearings and a single overhead camshaft in its aluminium head, uses Bosch L-Jetronic fuel injection in place of the twin SU type Hitachis. The compression ratio is 8.3 : 1 and the engine is happy to digest 91 octane fuel. Electronic ignition is fitted.
In this guise the straight-six delivers a modest 140 bhp DIN at 5,200 rpm compared with the 260Z’s 151 bhp, and 140 lb/ft of torque at 4,000 rpm compared with 151 at 4,400 rpm. The final drive ratio is unchanged, at 3.7:1, but the gearbox ratios seem to have been moved around a little, to incorporate lower first and second gears (specifics are difficult as Datsun sent out contradictory information, some years ago, on the 240Z v. 260Z transmissions). This lower initial gearing has failed to save the performance, which has deteriorated from round about the eight second to 60 mph mark to over 10 seconds and from a 126-127 mph maximum to under 120 mph, the claimed aerodynamic improvements notwithstanding.
The biggest disappointment is in low-speed performance. True, the engine is tractable at low speeds, but it is also exceedingly flat if any accelerative requirements are made of it below 4,000 rpm, which makes performance in the higher gears very uninspiring. Unless he works the engine hard through the gears, the 280ZX driver can be left straggling by cars which are more pedestrian in appearance than this sporting design. Even wound up to high speeds it is a little pretentious compared with its predecessor: I was surprised to find an early Silver Shadow could hold it between 70 and 90 mph, while I found it impossible to shake off a late (and therefore heavy and emission-stifled) Series II XJ 4.2 in a straight line, both of them automatics against the test ZX’s five-speed. manual. The automatic transmission option on the ZX is not an extra I could happily contemplate ….
On the other hand the high geared ZX is a very smooth and long-legged cruising car, very relaxed whether at 50 or 100 mph and much quieter and more refined than the old Z. High speed stability is first class. This is one sports car perfectly suited to long distance motorway travel. Its town behaviour is disappointing, however, in spite of the engine’s flexibility. The trouble lies with the complicated throttle linkage, which operates jerkily at small openings. I put this down to a fault in the test car, but the Janspeed turbocharged version tested below was exactly the same, as is a friend’s 280ZX 2+2 automatic; his dealer has told him that the problem is inherent and incurable. The clutch is not particularly progressive either and smooth stop-start progress in town needs more than usual – and tiring – concentration. The test car had a slight hesitancy and misfire between 1,000 and 1,500 rpm to compound the problem. There is a transmission whine in the lower gears. Connsumption worked out at 19-20 mpg: Government figures quote 27.7 mpg at a constant 75 mph, so the touring range is excellent.
A much more satisfactory story can be told about chassis behaviour. The suspension is independent all round as before, with McPherson struts at the front, but the rear struts have been replaced by a semi-trailing arm arrangement and the brake reaction arms which locate the bottom of the front struts are now in tension instead of compression. Those American market considerations have led to the adoption of variable ratio, recirculating ball type power steering, made under licence from ZF. This is standard in the UK, but manual rack and pinion steering is available in some markets. For those who might question the change, it’s worth noting that the power steering offers gearing of 2.7 turns lock to lock against a more elbow-twirling 3.5 for the manual.
My initial feelings were of disappointment, for the ZX feels softer than the old Z. This is deceptive, for in practice the handling under most circumstances is just as good as that of its predecessor and the roadholding is considerably better, the grip of the test car’s 195/70 VR 14 Michelin XDX tyres mounted on alloy wheels being superb. I prefer the old Z’s tauter handling around twisting lanes, but the ZX is the superior car on faster roads, becoming smoother and more neutral with speed. In fact everything seems to improve with speed: the handling becomes more neutral, the steering, somewhat “bitty” at low speeds, becomes smoother and more positive and the knobbly low-speed ride takes on a comfortable transformation. Heavy braking and acceleration provokes plenty of squat and pitch, but damping is generally good and roll moderate. Bumpy corners do not ruffle the high speed handling and traction is very good.
One of the biggest improvements over the old Z has been to adopt disc brakes all round, those at the front being ventilated. It used to be far too easy to fade the old disc/drum set up, the limiting factor in the Z’s high-speed driveability. The new arrangement is both progressive and, for normal fast motoring, fade free.
In terms of creature comforts, the old Z was hard to beat in comparison with other ’70s sports cars, partially I suppose because Datsun were never hampered by the restrictions of designing a soft top version. The ZX continues the standard for the ’80s, with the obvious improvements evoked by years or so of development and customer demand. Let me start on a very sour note, however, the blame for which does not lie entirely at Nissan-Datsun’s door. Those who think that mid-engined cars are totally impractical in terms of lack of luggage space should try the 2-seater ZX in the road test specification, ie with conventional wheels and tyres. Almost the entire boot space is taken by the loose-floating spare wheel, leaving no space for a suitcase without removing the hinged luggage bay cover. The car in this guise is totally impractical for holiday motoring or even as a ferry to the airport. This nonsense is enforced by British legislation which makes illegal the intended space-saver wheel and tyre, designed to tuck neatly behind a cover in the right hand rear corner for other markets. Because the ZX has a larger fuel tank (17. 6 gallons) than the Z, there is no longer room for a conventional spare beneath the floor. Porsche have overcome the problem by issuing a disclaimer note with the space-saver tyre and membership of a car recovery club, so why not Datsun? They do, however, offer Dunlop Denovo tyres as a no-cost option, which obviates the need for a spare. I could not contemplate buying a ZX without them.
The boot area design is none too good anyhow. The rear shelf is lifted up by a hook and piece of nylon string attached to the strut on the rear hatch; two awkward to reach butterfly nuts have to be undone to remove the rear shelf. The carpeted division between the boot and passenger compartment is equally awkward to remove via two flimsy plastic fasteners. There must be better ways of designing this lot. Stowage for oddments is available in two small lockers, surmounted by big tubular handles behind the rear seats, an armrest cum stowage box between the seats and a lockable glove box.
The 280 ZX has good ergonomics and large, comfortable, cloth seats with headrests and a wide range of adjustments, including height. The gear lever falls nicely to hand, but while the change is excellent through the four lower gears, selection of fifth, up to the right, requires a determined effort. The vast bonnet area and big power bulge seem restrictive to forward vision at first, but one soon acclimatises to this. Rearward vision is quite good, though hampered by the seat backs. Instrumentation is excellent by any standards, auxiliary instruments in the centre of the facia being angled towards the driver and the big speedometer and tachometer in the main nacelle are very clearly marked. Aircraft-type orange illumination is used at night. All the main switches are steering column mounted. The heating and ventilation system is powerful and effective. An electronic check system on the facia illustrates with a big “OK” sign whether all the necessary major functions and lights are in working order.
Standard equipment is lavish, including a MW/LW push-button radio (annoyingly, the electric aerial retracts when the ignition is turned off, but has to be raised with a separate switch), halogen headlamps with a high pressure washing system, wash and wipe for the heated rear screen, a map reading light in the roof, a quartz clock and electric windows. I wish other manufacturers would follow Datsun’s lead with their electric windows; as well as conventional individual switches working on constant touch, there is a separate switch, with changeover facility, which will automaticaly send the windows to the extreme of travel at a single touch.
The £8,628 280 ZX is a comfortable, well equipped, two-seater grand tourer (if Denovos are fitted), with good handling and distinctive styling. But it does lack the performance sparkle of its predecessors, and that is where Janspeed Engineering come in …. CR.
A Datsun 280ZX with Janspeed’s Turbo Touch
It will be obvious from the foregoing road test that the standard Datsun 280ZX needs more “steam”. Even the more pedestrian driver is likely to be disappointed by the lethargy in the lower rev ranges. The running gear has the potential to cope with much more power than the claimed 140 bhp in this heavy car. To Janos Odor, head of Janspeed Engineering in Salisbury, the solution was obvious: turbocharging.
Janspeed had already developed very effective turbocharger kits for the 240 and 260Zs and with this in mind a number of Datsun dealers and customers were soon knocking at Odor’s door in a search for that sparkle which the 280ZX had lost. The fuel-injection engine needed a new approach – it wasn’t simply a matter of modifying the 240/260Z kits. In practice the kit evolved into one of the simplest that Janspeed have developed, since the retention of the injection means that no additional or alternative carburetters, choke or throttle cables or air cleaning system need be supplied.
The result is the most effective turbocharged engine I have tried, with the exception of the incredible Lotus Esprit Turbo. I gave high praise to Janspeed’s twin-turbo Rover 3500 SDI in the April 1979 issue of Motor Sport; this latest conversion is even more impressive and, more to the point, even more necessary. While the standard Rover 3500 has plenty of performance, enough to please most people – in standard form, the 280ZX desperately needs the turbo touch. This is a true transformation, not just in outright performance, but in general flexibility and driveability too. In 2 plus 2 guise and fined with Denovo tyres to give boot space, Janspeed’s red demonstration car was a very desirable, very refined, 130 mph Grand Touring car. The long-wheelbase four-seater has even more weight to carry than the standard two-seater tested above, yet the test car could acceleraie from 0-60 mph in under 8 secs, to 100 mph in around 21 sec, and, even more pointedly, knock nearly 8 sec off the 70 to 90 mph fifth gear acceleration time.
But that isn’t all. There was real punch and crispness in that normally flat area below 4,000 rpm, so that even “quick burst” acceleration at low speeds, say in town traffic or pulling out of junctions into traffic streams, was vastly improved. Low speed flexibility was better than ever and throttle response showed no noticeable lag. The silencing effect of the turbocharger made the engine quieter than normal, with only an occasional distant whine to give away its presence and the standard car’s instant hot or cold starting and good cold drive-away characteristics were unimpaired. My only criticism was reserved for that jerky throttle linkage referred to in the standard car test – the turbocharger installation, alas, does not require an alternative linkage. Hard driving brought the consumption down to 16.93 mpg, but less use of full boost should give figures as good or better than standard.
The Rotomaster Turbosonic turbocharger, boosting at a maximum 6 psi, fits on to an adaptor on the standard exhaust manifold. By simply reversing the position of the Bosch fuel-injection air metering unit it is brought into alignment with the compressor side of the turbocharger. A Janspeed cast aluminium alloy inlet manifold links the compressor outlet with Datsun’s own inlet manifold. A pair of extra fuel injectors are mounted in the Janspeed inlet manifold to give extra injection under boost, because when the inlet pressure is at 6 psi the engine is moving 25 per cent more air volume than normal and extra fuel is required to maintain the correct air/fuel ratio. The extra fuel is injected as a result of signals from a pair of electrostatic pressure-sensing switches mounted on the inlet manifold, set to operate at 2 psi and 5 psi respectively. A wastegate mounted in the Janspeed inlet manifold restricts boost to 6 psi above atmospheric pressure. Air is taken from the atmosphere via the massive standard air filter which runs across the full width of the car’s nose. The kit is completed by an oil cooler and a large diameter exhaust downpipe which links with the standard exhaust system.
This is a true, bolt-on kit without any real fitting complications. The standard compression ratio of 8.3 : 1 is retained and the timing and injection settings are unaltered, so any competent mechanic should be able to cope with its installation. The ex-works price of the complete Janspeed Turbocharger Kit is £680 plus VAT. Janspeed quote a charge of £175 plus VAT should the customer require the kit to be fitted at the works, which have recently moved to 28,000 sq ft premises at Castle Road, Salisbury SP1 3SQ (Tel: 0722 21833/4/5/6). – CR.