THE HONDA NSX/NSX-T THE ULTIMATE DRIVER’S CAR

Honda’s NSX is one of those rare cars that has stood the test of time. The recipient of wide acclaim, both at launch and since, it remains today one of the world’s great sports cars, renowned for its sensational handling ability, relentlessly powerful engine, and advanced weight-saving technology.

Now this all-aluminium tour de force takes a giant step forward in performance with several major enhancements, including a larger, more powerful 3.2 litre V6 engine, a new 6-speed manual transmission and significant revisions to the powertrain, brakes and steering.

Key features in the new model line-up are:

•Choice of two engines: 3.0-litre mated to automatic transmission; and new 3.2-litre mated to 6-speed manual transmission

•NSX and NSX-T available with either 3.0-litre or 3.2-litre engines

•Potent new 3.2 litre V6 produces 206 kW (280 PS) at 7,300 rpm and 298 Nm (224 lb ft) of torque at 5,300 rpm - power to weight ratio up 2.5 per cent compared with the previous 3.0-litre manual model

•Advanced metallurgical technique, Fibre Reinforced Metal, used for cylinder liner construction on 3.2-litre engine - provides enhanced rigidity and saves weight - down by 3.0 kg despite power boost

•New stainless steel exhaust manifold on 3.2-litre contributes to power increase

•Outer body panels made from a newly developed aluminium alloy that is up to 40 per cent stronger, thus requiring less metal to perform effectively

•All-new 6-speed close ratio manual transmission

•New dual-mass flywheel clutch system

•Larger brakes with improved fade resistance

•Refinements to innovative Electric Power Steering system

•Reshaped front spoiler

•Highly efficient heat-absorbing green window glass

•New vehicle immobiliser system

An aluminium masterpiece

The NSX is the car that redefined the mid-engined supercar formula upon its launch in late 1990. No longer did exotic, high-performance sports cars automatically equate to a temperamental, flawed character holding pitfalls for the unwary or inexperienced. The NSX was ultimately forgiving, a car that flattered the ability of ordinary drivers, yet immensely rewarding for those more skilled. And it combined supercar performance with traditional Honda values, such as refinement, comfort, reliability and the highest build quality.

As the world’s first mass produced car with an all-aluminium body, it became an instant technological milestone in automotive development. The decision to build the car exclusively of aluminium followed an intensive research effort, from which Honda concluded that it was the most efficient way to meet the stringent rigidity and weight targets set. In particular, it meant the NSX would enjoy a high power to weight ratio. The result was a new breed of supercar combining awesome power and chassis dynamics with every day usability.

The latest NSX is even more potent. The brand-new 3.2-litre engine is another normally-aspirated VTEC masterpiece producing remorseless power up to its 206 kW (280 PS) peak at 7,300 rpm. Maximum torque is a massive 298 Nm (220 lb ft). Matching this is a brand new 6-speed manual gearbox providing even greater flexibility, an uprated braking system for prodigious stopping power, and electric power assisted steering which has been improved for even greater precision and feel.

The neutral, fully exploitable and unwaveringly secure chassis, the recipient of so much praise, remains unchanged.

To counter the small weight increase of the 6-speed transmission and larger brakes, key body panels are now made from a new aluminium alloy. This thinner, lighter weight material is used in making the doors, wings, bonnet and boot lid. Despite the many improvements in specification, 1997 models show only a very small increase in overall weight.

The NSX continues as both a fixed head coupe and as the open top NSX-T with removable roof panel catering for wind-in-the-hair aficionados. As well as the new 6-speed manual transmission, NSX customers can still opt for the Formula 1-inspired F-matic automatic transmission which gives the driver the choice of shift-it-yourself clutchless changes using a fingertip stalk located on the steering column; or the ease and convenience of automatic gearchanges in the conventional manner. The F-matic transmission continues to be matched to the familiar 188 kW (256 PS) 3.0-litre V6.

There are four models in the 1997 range: the NSX and the NSX-T fitted with either the 3.0-litre engine and F-matic transmission, or the 3.2-litre engine and 6-speed manual.

THE HONDA NSX/NSX-T BODY

From its exceptionally low nose, through the flowinglines of the large cockpit area with its abundance of glass, to the long spoiler-bedecked tail, the NSX has undoubted presence and looks that belie the fact that it made its debut almost seven years ago. A mid-engined supercar in the classic sense, the purposeful stance of the NSX does not deceive: the inherent promise of performance in abundance is indeed the reality.

For 1997 revisions include a reshaped front spoiler and the addition of a high mounted brake light. Two new body colours are also introduced: Imola Orange and Monte Carlo Blue.

Weight optimisation

Millions of Finite Element Modelling (FEM) and stress analysis calculations using a Cray supercomputer were performed during development to arrive at a design that weighed as little as possible, yet fulfilled all Honda’s body strength and rigidity criteria. The result is a chassis that weighs 210 kg with doors, bonnet and boot lid installed, which is about 40 per cent less than a steel chassis, but with the same rigidity and impact protection.

The NSX structure is significantly stiffer than every other competitor currently on the market. To achieve this, the NSX now employs additional reinforcement including:

•At the base of the B-pillar where it joins the rocker panel

•A larger rear bulkhead crossbar

•A thicker boot leading edge panel

•A reinforcement web in the rear floor cross member

•An additional rib in the centre rear bulkhead section

•A redesigned and thicker walled rear roof rail section

•A redesigned front roof rail section with increased wall thickness

•A completely redesigned and thicker upper A-pillar

•A redesigned and thicker upper dashboard cross-member

•A redesigned front lower floor section with increased wall thickness

•In addition, a complex design of aluminium extrusion is used for the side sills, with a carefully braced internal structure

To counter the small weight increase of the new 6-speed transmission and larger brakes, outer body

panels are now made with a newly developed aluminium 6000 series alloy that is up to 40 per cent stronger, thus requiring less material to perform effectively. This thinner, lighter-weight material is used for the doors, wings, bonnet and boot lid, among other key parts of the NSX. The use of the alloy nets a 2.1 kg weight reduction.

Creating the NSX-T

Since the original coupe body was a carefully optimised structure to achieve the requisite levels of stiffness without resorting to excessive weight, removing the roof, an integral part of that structure therefore called for equally careful development. In the NSX-T, the sill members, the A-pillars and

windscreen arch, and the B-pillars and rear arch are all substantially reinforced in comparison. This achieves completely satisfactory levels of bending and torsional stiffness, yet the weight increase only amounts to around 40 kg.

The removable, body-coloured top of the NSX-T is made of aluminium. Weighing only 8.5 kg, it is easily removed by means of two latches located on the left and right side. Once removed, the panel can be stowed in a lockable housing under the rear glass hatch, set into the top of the engine maintenance cover; it therefore does not take up valuable storage space. When the roof is replaced, a dash indicator light will alert the driver if the latches are not properly closed. Once fitted, it is connected to the main security circuit, so that any attempt to remove it triggers the alarm.

The NSX-T also has specially profiled windscreen pillars and a windscreen header rail which are designed to direct the airstream up and over the passenger compartment and minimise wind buffeting at speed.

Inside the NSX

The NSX is a strict two seater with an interior designed to cosset its occupants, and to provide a feeling of snugness and intimacy without in any way being claustrophobic. This is achieved by seats that fit snugly at the hips, a cockpit that flows outward and upward to provide ample room for the head and shoulders, and a large glass area that creates a sensation of light and space. Occupants sit low, but an equally low scuttle means visibility is excellent; indeed, the driver’s potential field of view is 312 degrees, exceptional for a mid-engined car. To minimise the effects of solar loading in hot weather, Honda has introduced a highly efficient heat-absorbing green glass for 1997.

Naturally, the low seating position and the generally low slung cockpit also benefit the aerodynamic efficiency of the NSX.

The fascia and controls are designed for simplicity, since the primary function of the instruments is to relay information as clearly and as quickly as possible; the gauges are traditional analogue with white numerals on a black background. The tachometer and speedometer are bordered by the voltmeter, water temperature, oil pressure, and fuel gauges.

In keeping with a bodyshell constructed entirely of aluminium, the entire seat frame is made of lightweight stamped aluminium and uses fewer parts than a comparable steel seat; even the seat rails are made from aluminium extrusions.

Leather was a natural choice for the seat trim material; soft and durable, it is hand-stitched and hand-fitted to ensure the finest quality of finish. The seat facings, door inserts, steering wheel and gear shift knob are all leather trimmed in a choice of either black or tan.

Different density foams used in the seats provide a subtle balance between cushioning and support.

The NSX is fitted with both driver and passenger Supplemental Restraint System airbags as well as automatic seat belt tensioners; these use the same impact sensors as the airbags.

A compact climate control system has been developed specifically for the NSX. This is a fully automatic system, but the automatic function can be overridden and the system can be used in a fully manual mode. It uses environmentally friendly R134A refrigerants.

Bose sound quality

To provide a sound system of the highest quality, the NSX is fitted with a four-speaker Bose system, designed and calibrated specifically for the NSX’s unique acoustics and resonances. It provides the highest quality imaging and spatial dynamics for both the driver and the passenger.

The Bose Music System speakers are precisely aimed so that the pressure wave of the speaker closest to each occupant does not overpower the pressure wave from the speaker which is farthest away. This produces a balanced sound from each speaker and the net result is true stereo performance.

The AM/FM stereo radio/cassette features Dolby Noise Reduction and an FM diversity antenna system. The auto preset function will automatically lock on eight strong AM and eight strong FM stations and store them into the preset selector buttons. An optional CD changer is available.

Security alarm

The NSX is fitted with a sophisticated alarm. If an unauthorised attempt is made to enter or start the NSX, the horn sounds, and the flashers are activated. The system automatically arms 15 seconds after the doors are locked and is disarmed when a door is unlocked with the key. The system will even work with the roof panel of the NSX-T removed.

Key transponder immobiliser

There is also an immobiliser of the key transponder

type. A circular antenna set around the steering lock reads and verifies a radio code issued from a transponder in the fob of the ignition key. The immobiliser control unit works in concert with the engine ECU: if the code is incorrect, the engine will not start as the ECU cannot activate the fuel pump, fuel injection, ignition or starter motor.

Craftsmanship befitting a supercar

Befitting its supercar status, the NSX is subject to ameticulous build process. The prime objective of the low volume, high technology plant located alongside the R&D centre in Tochigi, Japan is the achievement of world-leading levels of quality. Rather than assembly on an automated line, the NSX is constructed at a series of work-stations by a number of teams. Each car is only passed on to the next area once a team is satisfied that the tolerances and goals required in the specifications have been met; each assembly station therefore also functions as an inspection station.

Engines receive equally close attention and each unit is assembled by an individual, highly skilled technician from start to finish to ensure the closest tolerances.

The NSX is painted in a 23-step process, including an aircraft-type chromate coating designed for use with aluminium. The use of a waterborne base coat achieves a clearer, more vivid colour and a smoother

THE HONDA NSX/NSX-T DRIVETRAIN

The highly praised 3.0-litre engine, with its high specific output, instant response and wide, usable power band continues in automatic transmission equipped models.

Two engines of high specific output

The quad cam, four valves percylinder, 90 degree V6 produces 188 kW (256 PS) at 6,600 rpm and 284 Nm (209 lb ft) of torque at 5,400 rpm. It redlines at 7,500 rpm.

New to the NSX line-up is a further development of the 3.0-litre engine: a 3.2-litre (3,179 cc), quad cam, four valves per cylinder 90 degree V6, producing 206 kW (280 PS) at 7,300 rpm and 298 Nm (220 lb ft) of torque at 5,300 rpm. This replaces the former 3.0 litre engine fitted to manual models (201 kW (274 PS)) at 7,300 rpm and 284 Nm at 5,400 rpm) and the greater capacity comes from a bore raised from 90 to 93 mm. For a normally aspirated engine of just 3.2 litres, the specific output is quite remarkable; the power to weight ratio is improved by 2.5 per cent. It redlines at 8,000 rpm. In place of the 5-speed manual gearbox comes an all-new 6-speed close-ratio transmission.

Both engines continue to provide the spine-tingling, aural delights for which Honda’s pedigree V6s have become renowned.

Both of these all-aluminium engines employ Honda’s renowned VTEC (Variable Valve Timing and Lift Electronic Control) technology which optimises volumetric efficiency at both high and low engine speeds. A Variable Volume Induction System works with the VTEC system to broaden the torque curve and increase peak power output.

The cylinder heads are low-pressure cast aluminium; inlet valves have been increased in diameter by 1 mm to 36 mm to improve cylinder breathing. Combustion chambers are a pent-roof design with generous squish area to promote swirl and enhance combustion efficiency.

The block’s aluminium alloy construction is both weight saving and durable and on the 3.0-litre engine is combined with steel cylinder liners. However, the new 3.2 litre engine features cylinder liners made using an advanced metallurgical technique called Fibre Reinforced Metal (FRM) in which alumina and carbon fibres are inserted into the aluminium alloy for enhanced rigidity - also adopted for the new 2.2-litre engine of the recently launched Honda Prelude. As a weight saving alternative, it is remarkably effective; despite increases in horsepower and displacement, engine weight falls by 3.0 kg.

The advanced 3.2 litre engine and FRM

Honda continues to be one of the leading exponentsof exotic materials in automotive applications. The company’s extensive research has brought considerable experience which is brought to bear wherever this can provide useful benefits in terms of enhanced performance and a generally superior product for the customer.

FRM in engine block construction is a perfect illustration of this. During casting, the cylinder block’s aluminium alloy is poured around cylinder cores composed of fibres of carbon and alumina which start to absorb the molten aluminium. Once complete, the cylinders are bored by removing most of the core material. However, the outer extremes are retained leaving a tough, wear-resistant composite cylinder wall, at least 0.5 mm thick, integral with the block but reinforced by the carbon and alumina fibres.

The greater strength provided by this process allows larger bores within the same external block dimensions and bore spacing, and makes open-deck block construction possible. The elimination of the steel cylinder liners makes the 3.0 kg weight reduction possible.

However, adopting FRM means that conventional aluminium pistons can not be used, since aluminium-on-aluminium is not a satisfactory combination for durability; to overcome this, the aluminium pistons are provided with an iron coating.



To ensure a positive seal with the new FRM cylinders, the head gasket is now made of stainless steel.

Titanium connecting rods

Another demonstration of Honda’s readiness to adopt advanced materials, where these can bring clear and tangible benefits, is the specially patented titanium alloy used in the construction of the connecting rods for both 3.0 and 3.2 litre engines. While common in Formula One and other race engines, the NSX represented the first application of titanium in a production car upon its launch. As well as being lighter than a steel equivalent and therefore reducing reciprocating mass for better high-rpm operation, they are also significantly stronger.

The crankshaft on the new 3.2 litre engine is a fully counterweighted forged-steel unit and to accommodate the increased power output, both piston pin and crankshaft pin diameters have been increased.

VTEC: A milestone in engine technology

At its introduction, Honda’s advanced VTEC wasundoubtedly a significant breakthrough in engine technology and an elegant solution to the age-old trade off between low-end torque and high-end power. This ingenious system is now a firmly established element of Honda engine design and its ability to provide vivid top-end output and remarkable low and mid-range flexibility makes for exhilarating on-the-road performance.

The VTEC principle is designed to maximise the amount of air-fuel charge entering, and the amount of exhaust gas leaving, the cylinders over the complete range of engine speed. Ideally, the valves should remain open for a longer duration at high engine speeds to give the gases sufficient time to overcome their inertia and to enter and depart from the cylinder. However, this would cause problems at low and mid range engine speeds where valves opening for too long would allow intake charge to leak back out and exhaust gases to leak back into the cylinder; ideally in this instance they should remain open for a shorter duration - and that is precisely how VTEC works. For each cylinder’s set of two intake or exhaust valves, there are three rocker arms and three corresponding lobes on the camshaft.

Each pair of intake and each pair of exhaust valve rocker arms is actuated by the two outboard low-rpm cam lobes from idle to around 5,800 rpm. Their short duration and low lift ensure good cylinder filling. Above 5,800 rpm, the ECU commands a spool valve to open, sending oil pressure to pins in the rocker arms. The pins lock the two outboard rockers to the third, centre rocker arm. Until this moment, this centre rocker arm has been independently following the contour of a separate high-lift, long duration cam lobe. Now the valves are actuated by the centre rocker arm and more closely match the induction and exhaust timing required for optimum torque at high engine speeds. The point of change from one phase to another, which occurs in 0.1 seconds, is virtually undetectable by the driver.

Variable Volume Induction

In addition to VTEC, the NSX uses a Variable Volume Induction System which is designed to work in concert with VTEC to improve both low-end torque and high-rpm power. The system features a secondary intake air plenum located beneath the main intake manifold and separated from it by six butterfly valves.

At 4,800 rpm these valves are opened by manifold vacuum and the added volume of the secondary plenum creates a higher resonance frequency, which in turn creates a sonic pressure wave. The sonic pressure wave hits each pair of intake valves just as they open, promoting more rapid and complete cylinder filling.

Programmed Fuel Injection

Honda’s advanced sequential port Programmed Fuel Injection (PGM-FI) provides carefully metered sequential delivery of fuel according to load and speed demands and is designed to fully complement the variable volume induction and VTEC systems. An air-assist mechanism aids fuel atomisation for better combustion at low temperatures. To provide additional fuel for the new 3.2 litre engine, the flow rate of the injectors has been increased by 15 per cent.

In the unlikely event of a transient engine malfunction, an onboard diagnostic system incorporated into the engine management system records and stores the information. This can then be retrieved at a later date through the diagnostic port to facilitate maintenance and repair.

To ensure a hot, stable spark at high rpm operation, the direct ignition system has an individual coil mounted atop each spark plug. The spark plugs themselves are centrally located for optimum flame propagation, and feature a platinum tip for improved durability and longer service life.

The lightweight exhaust system uses spherical joints rather than conventional flexible tubes to make further weight savings. The exhaust manifold of the 3.2 litre engine has been reconfigured and instead of cast iron is now made of stainless steel pipe for improved performance and reduced weight. The improved flow that results is a key contributor to the increased power output from the engine.

A large, 1.14 litre catalytic converter is mounted close to the engine for faster warm-up and time taken to reach peak efficiency, without compromise to power output.

6-speed manual gearbox

The all-new, compact, close-ratio 6-speed manual transmission now fitted to 3.2-litre models is designed to provide outstanding durability with short shift throws and quick, precise response. Dual-cone synchronisers

are used on the first four speeds for quicker, smoother gear changes, while a solenoid-type selection control mechanism smoothes the change from 5th to 6th. Reverse gear is also equipped with synchromesh. Shift load in this new gearbox has been decreased by between 40 and 50 per cent on 1st, 3rd and 4th gears.

The additional ratio provides the NSX with even more flexibility than the carefully spaced ratios of the old 5-speed manual; the 2nd to 5th gear ratios are now shorter, while the new 6th gear is seven per cent higher than the old 5th gear.

Dual-mass flywheel clutch

To handle the high torque and power output of the new 3.2 litre engine, a new dual-mass flywheel clutch system has been developed. The design involves a split flywheel which incorporates a grease-lubricated wide angle torsion mechanism.

The system is specially tuned to the NSX drive system and so gear rattle is effectively minimised. Clutch performance has been enhanced by a high performance friction material which allows the twin-disc pull-type clutch to be replaced by a single disc unit.

Torque Control Differential

A sophisticated torque control limited slip differentialfitted to manual transmission models helps to maximise their performance. It uses a multi-plate clutch and helical-type planetary gears. When the NSX is travelling in a straight line, the amount of slip between the rear wheels is controlled by preset spring-loaded disc imparting a force on the multi-plate clutch.

However, when differential wheel movement exists, the force of the spring-loaded disc is overridden by the thrust force of the helical-type planetary gears, and the friction developed in the multiplate clutch is increased. Since the limited-slip effect varies with the drive torque, it is a particularly effective control and vehicle behaviour is greatly improved. In particular, acceleration out of tight corners is improved by some 10 per cent because the tendency of the inner wheel to spin is reduced; and maximum acceleration on a split-mu surface (grip one side, slippery the other) is typically doubled.

F-matic automatic transmission

The introduction of F-matic in 1995 brought thesensation of the clutchless manual gearchange of the racetrack to a road going car. Inspired by Formula One technology, the F-matic transmission allows the driver to select the sportier, performance ‘feel’ of a manual - with ‘shift-it-yourself’ clutchless gearchanges - or to revert to the ease and convenience of automatic gearchanges in the conventional manner.

F-matic uses a conventional floor-mounted gear selector for the automatic mode; however, manual gear selection is made by means of a fingertip stalk located on the steering column, which allows both hands to be kept on the wheel while changing gear.

The shift position (PRNDM21) is depicted on the tachometer to provide the driver with an easily visible indication of the gear and mode selected. F-Matic is engaged by selecting the ‘M’ or manual position. In this mode, the shift position is illuminated in a window to the right of the shift lever position indicator. The fingertip control stalk is simply moved up to change up, and down to change down. A circuit in the central processing unit prevents holding on to, or changing to a lower gear, when that would cause the engine to over-rev.

Additional refinement of the automatic transmission shift programming - maximising the potential of the traction control system and drive-by-wire accelerator linkage - has helped to minimise transmission shock on downshifts during deceleration.

The automatic is also equipped with a programmed lock-up torque converter to improve fuel economy and reduce slippage. In the F-matic manual mode, lock-up is available in second, third, and fourth gears during both acceleration and deceleration.

Limited slip differential

The limited slip differential fitted to automatic transmission-equipped models is not of the torque sensing type fitted to manual models. It uses a multi-plate clutch and planetary gearset and reacts to the rotational difference between the rear wheels and attempts to maintain the same rate of rotation for both. In a strong crosswind which might cause the car to momentarily deviate, for example, the differential will detect the rotational difference between the two rear wheels and transfer torque to the slower rotating wheel. This has the effect of directing the car back into the desired path.

Traction control system

The aim of the traction control system (TCS) is to minimise rear wheelspin and is designed as a high-performance system rather than a pure low-speed traction enhancing device. Using information from the wheel-speed sensors of the ABS system, together with a lateral g sensor, the TCS detects the rotational differences between the front and rear wheels and engages at impending wheel slip rather than at the moment of wheel slip.

In such situations the engine management system is signalled to alter the amount of air and fuel delivered to the engine. As well as preventing wheelspin during acceleration, the TCS can also help to avoid the control problems which can result when the driver suddenly downshifts on a slippery surface. In some cases this can be enough to cause the driven wheels to lose their grip, and the car to yaw off-line. The TCS prevents this from happening by opening the throttle to apply just sufficient power to prevent the wheels locking, so that full control is retained. The driver can elect to disengage the TCS by a switch located on the dashboard.

For 1997, the system has been enhanced to reduce further shift shock during downshifts when the F-matic transmission is being used in its manual mode.

Drive-by-wire accelerator linkage

The NSX was the first Honda to use a drive-by-wirethrottle linkage, effectively replacing a long, convoluted mechanical cable with an all-electronic system. The system works by means of an accelerator pedal sensor, a throttle angle sensor, an electronic control unit and a step motor to control throttle opening and provide fail-safe - and indeed instantaneous - throttle operation.

A particular advantage of the drive-by-wire system is that the traction control, cruise control and idle speed functions are all integrated with the engine management system, allowing them to work in harmony and to enhance their precision.

The Honda chassis: a new pinnacle of handling

When the NSX was first launched, its tremendoushandling capabilities effectively rewrote the rule book. Suddenly the term mid-engined supercar no longer meant skittish, highly-strung machines with performance accessible to only the most skilled. Here was a car whose chassis ability reached a new plane, with truly confidence-inspiring poise, huge grip and always immensely forgiving. Even today it is acknowledged as a handling benchmark which serves to underline its dominance in 1990.

For 1997, the key chassis refinements are restricted to complementing the latest performance enhancements. The brakes are now larger, the anti-lock braking system has been refined, and the innovative variable electric power assisted steering system has been improved for better feel.

Double wishbones all round

The same suspension configuration is retained: double wishbones all round with a coil-over shock absorber and anti-roll bars front and rear.

In the constant quest to reduce unsprung weight, the race-bred suspension arms are made of extremely rigid and durable forged aluminium rather than steel. The front knuckle and the rear hub carriers are made from heat-treated aluminium castings. Springs are constant rate with a rubber bump stop mounted on the chassis to act as a progressive springing element at the limit of wheel travel.

The shock absorbers are nitrogen-filled and feature a unique valve design. The progressive opening of this valve produces a more favourable damping profile, and more precise damping control, than a conventional valve system in which the fluid control orifices are either fully opened or closed.

The NSX’s high rigidity provides a stable platform for consistent suspension geometry and alignment; it overcomes any possibility of the body acting as an undamped spring, feeding energy back into what might already be an overworked suspension system.

Front and rear suspension components are mounted on separate aluminium subframes using rubber bushings; these are designed to reduce vibration yet limit flex and shift of the suspension components relative to the subframes.

Honda engineers opted for forged-aluminium alloy wheels which offer light weight together with the strength and impact resistance of a much heavier steel wheel. Compared with cast wheels, they reduce weight by 9 kg. The rear wheels are 8.5 x 17 in, the front 7 x 16 in.

Tyre development meanwhile involved close cooperation between engineers from both Honda and the tyre manufacturers. The target was a tyre that would not only provide excellent traction and handling, but also allow the driver to ‘feel’ the limits of its performance.

The result is a uniquely designed, low-profile tyre which meets all the targets established early in the programme: excellent wet and dry weather traction, high-speed stability and immediate and predictable reaction to steering input. The tyres are unidirectional and specific to each corner of the car, while different compounds are used front and rear. Sizes of 215/45 ZR16 front and 245/40 ZR17 rear are retained for the 1997 NSX. A 165/75 D16 rather than a 165/80 D15 space saver tyre is now adopted as a spare.

Larger disc brakes

The high performance capability of the NSX demands highly effective stopping power and the brake system for 1997 has been significantly uprated to allow for the increase in engine performance. Large ventilated discs all round with dual-piston steel callipers are retained, but disc diameter is increased from 282 mm front and rear to 298 mm front and 303 mm rear. To accommodate the larger discs, new callipers have also been fitted. Combined with new piston sizes, a better braking balance has been achieved. Splash guards with cutouts aid ventilation and enhance fade resistance.

The four-channel anti-lock braking system (ABS)controls each wheel independently with a 16-bit microprocessor. This four wheel independent capability allows fine control of the ABS, especially when the car is braking on a surface with a split coefficient of friction - for instance, if the wheels on the left are on a dry surface, but those on the right are on ice or standing water.

The basic configuration is independent parallel hydraulic circuits. In addition to the primary, non-anti-lock braking circuit, the anti-lock system has its own hydraulic reservoir, pump, modulator unit, solenoids and control pistons. If a failure in the anti-lock hydraulic circuit should occur, normal braking force will be fully retained by the primary braking circuit.

Electric power steering

The introduction of speed sensitive electric power steering in the NSX was another clear demonstration of Honda’s enviable record of innovation and ability to bring advanced products to the marketplace. Its effect is to provide instant response, informative feedback and assistance only when really required. The system consists of a high ratio rack and pinion steering gear with an electric motor installed concentrically around the steering rack. A speed sensor in the system’s electronic control unit determines road speed and, coupled with a torque sensing system, feeds a signal to the electric motor to provide varying levels of assistance. Since the system removes the need for a hydraulic pump, it does not take power away from the engine; it is also lighter.

The steering system is a direct design which functions with no assist at higher vehicle speeds. To ensure reliability, the electrical system features gold-plated connectors.

Refinements in the ECU for 1997 have significantly improved feel and steering stability.