When They Were New Back Story: 1998 Honda Prelude Type SH and 1998 Acura NSX

by Nicholas Frankl
The Auto Channel
HOT CAR GUY

Speak softly - but carry a big stick. Now there is a quote for Honda Motor Co if I ever heard one. The company that brought us marvels like 4-wheel steering and a total domination of Formula One amongst other things seems to a have a serious personality disorder. On the one hand the Japanese giant is happy to play Mummy & Daddy - churning out respectable - but let's face it rather uninspirring grey cars, that loyal hat wearing (and we're not talking street rap side facing baseball caps here), customers buy year on year till death does them apart. Who can blame them as these gentle folk propelled the Accord to No1 best selling car in America.

BUT! on the other hand of this tortured sole is the fire breathing high revving technological wonder that drivers, not merely motorists, seek out and enjoy. If the letters VTEC and NSX make up part of your vocabulary then you might want to add some more abbreviations to your petrol-head dictionary - ATTS and Type SH. They belong to the new 220 Bhp, 150mph Prelude. That's the good news, in fact just the start of it. The bad news is that Honda UK have imported only two cars, and those aren't even for sale as the cars are not homologated for Europe or anywhere else outside Japan.

Enough, enough, ha! Actually it gets worse, because this little red rocket is actually a very good car indeed, the Automatic Torque Transfer System goes along way to helping the Bridgestone Expedia tyres to grip tirelessly into and through corners. Now, I am not one for all these hoe-cous poe-cous gadget thingymagigs but somewhere underneath, lurking in a black box microprocessor is a chip sending a diode all the right messages or something like that, but let's not get too technical.

The bottom line is that this yellow peril is just what the urban commuter needs, combining a great stereo, sorry that's a misprint, I meant to say unbelievably ridiculous hi-fi unit that packs a fifty - yes a five with a zero after it - CD player in the boot (they couldn't quite fit it into the glove box) with about 25 speakers, a mobile remote control and voice activation. Pioneer claim it's a must have- although I found it difficult enough to just turn on, eye catching looks, a good set of wheels matched with excellent Bridgestone rubber and a sexy third mid mounted brake light. These are the delays I love, of course it has enough space for four - although rear space is a cramp affair, a large boot with low, easy loading, sill and a rev counter that doesn't run out till somewhere around Pluto.

The beauty of this engine as with other lesser stimulated variants, is that below say 4500 revs the mother-in-law would never suspect that her daughter has run off with the local Andy Green impersonator (he who drove Thrust SSC to Mach 1 and above). However, one unrestrained gear change and whollop she's doing 70 mph in second and screaming for her daughters alimony. Basically this Type-R business is bloody quick, best of all, no-one - par aficionados - will ever know and that goes for smokey Bears too. Now Mr Kawamoto, oh Pleeeease can we have some?

Enough teasing of the delicacies we can't have how about the NSX you can buy?

1990 was the year Japan assaulted the sports car market. Toyota bombarded us with the Celica, Nissan marched in with the ZX300 and Honda (with the help of Ayrton Senna) serenaded the Tifosi with the ultra modern NSX. Seven years later and the shape has hardly changed a bit, still angular and low with the distinct long tail and fighter plane type glass cockpit.

Some of the original TACH readers might recall a fabulous journey I made last year ('96), down to the Monaco GP and back in convoy with my father in a 328, it's certainly a trip I won't forget, made all the more memorable by the gentle purring / screaming of the V6 motor ricocheting off the Southern Alps . At the time my complaints were few - the main one, that of a need for slightly more horses, I am pleased to say has been rectified.

The 1998 NSX comes with a modified version of the previous engine, this time we have 290bhp, not 270 and six gears rather than five. The real difference though is in the feel of the car. The gearbox is closer of ratio and shorter of throw, making two finger changes a joy, in fact my favourite was holding the handbrake with my left hand at the lights and gently sliding the thick black leather gear-nob into first with my thumb. Sounds silly but it felt so good. It's not the only thing. The engine is fantastic. It's appears to work in three stages, up to 3800 purring quietly, above, and until 5500 the note and the pull becomes stronger, but the real effort is reserved for the higher reaches - lift off, I'm talking cams not rockets, runs all the way to 8900. Into the red line the car feels it could reach into five digit territory - only the limiter spoiling the fun. I don't know how many times I went round my local "test" roundabout, most of the time it was sideways or drifting, the wet test being particularly memorable - and tricky! The TCS (traction control system) works well, but don't be fooled , it's not like the systems you find on Mercs and Beemers- the car can get sideways very easily and personally I find it crucial to be able to control the car with the throttle - something you can't do with TCS on. Although Honda claim that the system will actually open the throttle to prevent over correction or tank slapping. The steering is direct, but a little on the heavy side, masking slightly what's going on up front, the seats, electronically controlled, are simple and superb, although if you took away all the motors and gubbings it would cure the lack of headroom problem for 6 footers n' above.

Those inch's can be found by simply removing the targa top and slipping it into the specially designed engine cover - none of that ridiculous nonsense you get with the Diablo roadster, with half the roof slung out back like some half baked roof rack.

The problem for Honda is that in 1991, the NSX battled with the likes of the old Lotus Esprit, the Ferrari 348 (not a memorable car) and the 911 Carrera 2. Now, it's a different world out there. Hello 355, Esprit V8 and new 911, not to forget the young pretenders like Venturi, Spectre and TVR. The fact that this latest variant can still hack it with the best of them is a credit to it's makers engineering excellence and brute stubbornness For, truth be told, if any other manufacturer had spent the billions of Dollars Honda invested, only to sell so few in each market (less than 50 in '97 in the UK compared with 400 Ferrari's) and worst of all not have gained the publics acknowledgement of this great super car, it would surely have died long ago.

For this we must thank the Japanese spirit of commitment.

Sayonara.

1998 Acura NSX - Overview

The intention in creating the Acura NSX, which was first introduced for the 1991 model year, was to produce a hand-built, exotic, mid-engine sports car that would establish entirely new levels of prestige, performance, refinement, driveability and reliability. The aluminum-bodied NSX is designed to represent an entirely new definition of the exotic sports car through state-of-the-art, lightweight technology.

As the NSX has evolved during the 1990s, it has been hailed as a technological showcase.

The NSX-T model introduced during the 1995 model year, which features a removable roof panel, created a different level of excitement and broadened the appeal of the NSX. It also succeeded in maintaining the extremely high levels of performance and sophistication established by the NSX coupe. It also included technological achievements such as an optional Formula One-inspired SportShift automatic transmission with a unique column-mounted electronic shifter, a drive-by-wire throttle system, standard variable electric power-assisted steering, a compact and efficient system pioneered in the first-year NSX equipped with the automatic transmission.

The 1997 NSX/NSX-T took a giant step forward in performance with several major enhancements - most notable of which is a larger, more powerful 3.2-liter, 290 horsepower, V-6 engine with a 6-speed manual transmission.

Additional significant engineering updates also include larger brakes and improved anti- lock braking system, refinement to the Electronic Power Steering system, application of new aluminum alloys for lighter-weight, high-rigidity body panels, adoption of special heat-rejecting window glass and an anti-theft vehicle immobilizer system.

Throughout 1998, the NSX continues as Acura's ultimate exotic sports car by combining world-class performance, styling and prestige with exceptional refinement, driveability and reliability.

CONCEPTS AND GOALS
In designing the original NSX, light weight was chosen as the core technological path leading to the following attributes:

• Top-rank performance equal to or greater than existing exotics;
• Excellent liveability. The NSX had to be as easy to live with as any other Acura;
• Outstanding handling;
• A high level of comfort and ergonomic design, and low ambient noise level;
• Reliability and durability equal to mass-produced automobiles;
• Extremely high level of fit, finish and materials;
• Limited production;
• Excellent climate control system that could keep the occupants comfortable under any weather condition.

The NSX achieved all of these goals and established itself on a level equal to or greater than existing exotic sports cars. Goals for the NSX-T included all the original attributes of the NSX, plus the intangible excitement of open-air motoring. Priorities included:

• Excellent body rigidity for precise handling;
• Outstanding levels of noise insulation;
• Providing a convenient storage compartment for the roof panel;
• Minimizing wind buffeting at speed;
• Providing a security system that functions with the top removed.

OVERVIEW
The mid-engine, 2-seater NSX offers two distinct powerplants. The standard engine is an all-aluminum 3.2-liter V-6 that produces 290 horsepower and 224 lbs-ft of torque, and features a 6-speed manual transmission. An electronically controlled 4-speed automatic transmission with Formula One-inspired SportShift mode is optional and comes with an all-aluminum, 3.0-liter V-6 which produces 252 hp and 210 lbs-ft of torque.

Both engines are normally aspirated and are equipped with dual overhead cams, four valves per cylinder, a Variable Valve Timing and Lift Electronic Control (VTEC) system, and a Variable Volume Induction System intake configuration. They also offer Programmed Fuel Injection (PGM-FI) and a direct ignition system that uses an individual coil mounted atop each spark plug instead of a single coil for the entire system.

The chassis features all-aluminum construction for light weight. The 4-wheel independent double-wishbone suspension also features aluminum-alloy control arms and hub carriers front and rear, and aluminum subframes for the front and rear suspension. The braking system features large-diameter, ventilated 4-wheel discs, and an advanced 4-channel Anti-Lock Braking System (ABS). The sophisticated Traction Control System (TCS) has been designed to help limit wheelspin and enhance control.

1998 Acura NSX - Powertrain

OVERVIEW
The standard engine on the NSX is an all-aluminum, 90-degree, 3.2-liter (3179 cc), dual-overhead-cam, 4-valve-per-cylinder V-6 which produces 290 horsepower at 7100 rpm and 224 lbs-ft of torque at 5500 rpm. It is mated to a 6-speed close-ratio manual transmission. Redline is at 8000 rpm.

The optional electronically controlled 4-speed automatic transmission comes with an all-aluminum, 90-degree, 3.0-liter (2977 cc), dual-overhead-cam, 4-valve-per-cylinder V-6 which 252 horsepower at 6600 rpm and 210 lbs-ft of torque at 5300 rpm. Redline is at 7500 rpm.

An exclusive electronically controlled Variable Valve Timing and Lift Electronic Control (VTEC) system optimizes volumetric efficiency at both high and low engine speeds. A unique Variable Volume Induction System changes the configuration of the intake system with varying engine speeds, working with the VTEC system to broaden the torque curve and increase peak power output. The 3.2-liter engine boasts a stainless steel exhaust header system to improve engine breathing.

ENGINE BLOCK, CYLINDER HEADS, CRANKSHAFT, PISTONS
To achieve both light weight and durability, the engine block is made of aluminum alloy. While cast iron cylinder liners are used on the 3.0-liter engine, the cylinders on the 3.2-liter V-6 are now made using an advanced metallurgical technique called Fiber Reinforced Metal (FRM), in which an alumina-carbon fiber is cast into the traditional aluminum alloy for enhanced rigidity. This process not only allows displacement to be increased without increasing bore centers, it provides outstanding cooling characteristics and reduces weight.

The 3.2-liter engine has cylinder bore surfaces consisting of an 0.5-mm-thick layer with fibers of carbon and alumina (aluminum oxide, or Al2O3) in the aluminum alloy. In production, the cylinder block's aluminum alloy is poured around cylinder cores composed of these two fibers. The cores absorb the molten aluminum during the casting. After casting, the cylinders are bored to a slightly smaller diameter than the cores, leaving a tough, wear-resistant, composite cylinder wall integral with the block but reinforced by the fibers. The process allows larger bores within the same external block dimensions and bore spacing, and makes open-deck block construction possible. In turn, this is appropriate for the new NSX engine's higher performance level. And with the elimination of iron cylinder liners, the reduction in engine weight by 2.4 kilograms was made possible.

In the 3.0-liter engine, conventional aluminum pistons are normally used. Because aluminum-on-aluminum is not a satisfactory combination for durability with a piston sliding in a cylinder, the 3.2-liter aluminum pistons are given an iron coating. The piston crown has been reshaped to improve heat resistance, and the pin diameter enlarged to cope with the higher output.

The crankshaft on the NSX engine is forged unit made of a special high-strength steel to cope with the high power output of both engines.

The cylinder heads are low-pressure cast aluminum. To increase flow into the combustion chamber in the 3.2-liter engine intake valves have been increased by 1 mm to 36 mm. Even though the valve diameter was increased, a unique cup shape was incorporated into the valve head to allow it to maintain the same weight. To further increase flow by creating a gentle radius leading from the port into the combustion chamber, a special 4-angle valve seat machining process is used - a process typically reserved for racing applications. The head gasket on the 3.2-liter V-6 is now made of stainless steel to ensure a positive seal with the new FRM cylinders. The combustion chamber for both engines is a pent-roof design with generous squish area to promote swirl and enhance combustion efficiency. The spark plug is centrally located for optimum flame propagation, and features a platinum tip for improved durability and longer service life.

TITANIUM CONNECTING RODS
The connecting rods are made of a specially patented titanium alloy. While titanium rods are common in Formula One and other race engines, this is the first application of titanium in a production car. Compared to a steel connecting rod for the same engine, these titanium rods each weigh 190 grams less and are significantly stronger. To cope with the increase in power, the 3.2-liter engine's piston pin diameter has been increased by 1 mm (from 22 mm to 23 mm), while the crankshaft pin diameter was increased by 2 mm (from 53 mm to 55 mm).

To accommodate the larger crankpin diameter, the connecting rod bolts were moved 1 mm farther apart and incorporate a new, high-strength design. The rod bolts used are actually stronger, yet 1 mm smaller in diameter and 20 percent lighter than those previously installed.

VARIABLE VALVE TIMING AND LIFT ELECTRONIC CONTROL (VTEC) SYSTEM
Without question, the Variable Valve Timing and Lift Electronic Control (VTEC) system is recognized as a breakthrough in engine technology. It convincingly solves the age-old trade-offs between low-end torque and high-end power.

The heart of the VTEC system is a unique camshaft and rocker arm system. For each cylinder's set of two intake (or exhaust) valves, there are three rocker arms and three corresponding lobes on the camshaft. The two outboard lobes each have a profile suited for low- to mid-rpm operation. The third, or center cam lobe has a dramatically different profile designed for longer duration and higher lift. This lobe profile is designed to optimize breathing and horsepower production at high engine speeds. At low engine rpm, the valves are operated by the outboard lobes. During high-speed operation above 5800 rpm, the VTEC computer sends a signal to a spool valve, which in turn delivers engine oil to small pistons in the rocker arms. Oil pressure causes the pistons to slide, locking all three rocker arms together. Once locked, the rocker arms are forced to follow the center cam lobe, increasing top end performance. The crossover from low lift to high lift occurs in 0.1 seconds and is virtually undetectable to the driver.

VARIABLE VOLUME INDUCTION SYSTEM
In addition to VTEC, the NSX engine also uses a Variable Volume Induction System. This system uses a separate intake air plenum, located beneath the main intake manifold. This second plenum is separated from the primary manifold by six butterfly valves, which open between 4600 and 4900 rpm and are actuated by manifold vacuum.

When the valves open, the added volume of the secondary plenum creates a higher resonance frequency, which in turn creates a sonic pressure wave. This sonic pressure wave hits each pair of intake valves just as they open, promoting more rapid and complete cylinder filling. This system was designed to work in concert with VTEC to improve both low-end torque and high-rpm power.

FUEL INJECTION
Programmed Fuel Injection (PGM-FI) ensures that each cylinder receives the precise amount of fuel necessary for the present load and speed conditions. This system has been specially tailored to the unique capabilities of the induction and VTEC systems. An air-assist mechanism aids fuel atomization for better combustion at low temperatures. To provide additional fuel for the new 3.2-liter V-6, the flow rate of the injector has been increased by 15 percent.

ONBOARD DIAGNOSTIC SYSTEM (OBD-II)
An onboard diagnostic system incorporated into the engine management electronics system records and stores information on transient engine malfunctions. These can be retrieved through the diagnostic port to facilitate maintenance and repair.

EXHAUST SYSTEM
The NSX features a lightweight, highly efficient exhaust system. On the new 3.2-liter V-6, the exhaust manifold has been reconfigured and is now made of stainless steel header pipes rather than a cast-iron manifold for improved performance and lighter weight. Increased flow from this new configuration is a key contributor to the 20 additional horsepower drawn from this new engine.

The catalytic converters displace 1.14 liters and are close to the engine for quick converter light-up and a consequent reduction in emissions but without any sacrifice in power output. The overall weight of the unit has also been minimized by using spherical joints in the exhaust system rather than conventional flexible tubes.

DIRECT IGNITION SYSTEM
To ensure a hot, stable spark at high rpm operation, the ignition system has a coil mounted atop each spark plug, a design similar to that used in Formula One racing engines.

MANUAL TRANSMISSION
A compact, close-ratio 6-speed manual transmission is designed to provide impressive durability with short shift throws and quick, precise response. Dual-cone synchronizers are used on 1st through 4th gear to reduce shift load from 40 to 50 percent for quicker, smoother shifting. Reverse gear is also equipped with synchromesh. To increase performance while maintaining excellent fuel economy, the five first ratios have been lowered while 6th gear is 7 percent higher than 5th gear in the previous NSX. A reverse lock-out solenoid ensures proper gear selection when shifting into 6th gear.

"HEAVY-DUTY" CLUTCH
To handle the high torque and power output of the 3.2-liter V-6, a dual-mass flywheel clutch system was developed. The design involves a split flywheel which incorporates a grease-lubricated wide-angle torsion mechanism. Gear rattle is effectively minimized because the system is specially tuned to the NSX drive system. Clutch performance is maximized by a high-performance friction material on the low-inertia mass clutch disc while the relocation of the torsion mechanism to the flywheel side helps retain a light clutch feel.

SPORTSHIFT AUTOMATIC TRANSMISSION
The optional SportShift 4-speed automatic transmission allows the driver the option of letting the transmission shift automatically in a conventional manner or selecting each gear manually by means of a fingertip control shift lever on the steering column. Inspired by advanced Formula One transmissions, this dual-mode system was created to give the driver of an automatic the same sporting performance feel of a manual. Unlike other similar systems, this one allows the driver to keep both hands on the wheel while selecting a gear. This feature adds to the safety of the vehicle by allowing the driver to concentrate his full attention to the road ahead.

The shift quadrant (PRNDM21) is depicted on the tachometer. SportShift mode is engaged by selecting the M, or manual, position. In M mode, the shift position is illuminated in a window to the right of the shift quadrant. To shift up, the fingertip control lever is moved up, and to shift down, the flipper lever is moved downward. A circuit in the CPU (central processing unit) prevents downshifting that would cause the engine to over-rev.

Precise automatic transmission shift programming has resulted in minimal shock when downshifting while decelerating, maximizing the potential of the Traction Control System (TCS) and drive-by-wire throttle system.

The automatic is also equipped with a programmed lockup torque converter to improve fuel economy and reduce slippage. In the SportShift manual mode, lockup is available in second, third and fourth gear during both acceleration and deceleration.

TORQUE REACTIVE DIFFERENTIAL
The torque reactive limited slip differential minimizes spinning the inside wheel on NSX models equipped with the 6-speed manual transmission. This unit uses a multi-plate clutch and helical-type planetary gears. When traveling in a straight line, the amount of slip between the rear wheels is controlled by the force of a preset spring-loaded disc imparting a force on the multi-plate clutch. In a tight corner, however, the force of the spring-loaded disc is overridden by the thrust force of the helical-type planetary gears, thus preventing the inside wheel from spinning and enhancing stability.

TORQUE CONTROL DIFFERENTIAL
The torque control differential employs a multi-plate clutch and planetary gearset to help maintain vehicle stability at speed in crosswinds and when driving over split-friction surface conditions. The unit reacts to the rotational difference between the rear wheels and attempts to maintain the same rate of rotation for both wheels.

If the NSX should be forced off the intended direction in a crosswind, 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. This differential is on automatic transmission-equipped models only.

TRACTION CONTROL SYSTEM (TCS)
The goal of the Traction Control System (TCS) is to minimize rear wheelspin on slippery or uneven road conditions. This unique development was created as a high-performance system rather than purely a low-speed, traction-enhancing device. The TCS uses the wheel-speed sensors of the Anti-Lock Braking System (ABS) and a G-sensor to detect rotational differences between front and rear wheels and lateral acceleration. If the computer determines the surface is slippery, Central Processing Unit (CPU) signals are sent to decrease the amount of air and/or fuel delivered to the engine. The driver can disengage the TCS via a switch on the instrument panel. Using ABS wheel-speed sensors and working in conjunction with the drive-by-wire throttle system, the TCS engages at impending wheel-slip rather than at the moment of wheel-slip. A logic circuit also controls stability during sudden deceleration on slippery surfaces. The system has also been enhanced to reduce shift shock during manual downshifts with automatic transmission-equipped models.

DRIVE-BY-WIRE THROTTLE
The drive-by-wire throttle system replaces a conventional throttle cable arrangement with an all-electronic system that senses the throttle pedal position and relays that information to a computer. The computer, in turn, performs the actual throttle activation instantaneously. The system works by means of a throttle pedal sensor, a throttle angle sensor, an electronic control unit and a step motor to control throttle opening and provide fail-safe throttle operation. It works in harmony with the TCS to provide a broad range of control. This system also helps to enhance the precision of the cruise control system.

1998 Acura NSX - Chassis

OVERVIEW
Outstanding handling characteristics have been a hallmark of the NSX and NSX-T since their inception. A sophisticated all-aluminum, double-wishbone suspension provides outstanding ride and handling, while large, 4-wheel, disc brakes and a 4-channel Anti-Lock Braking System (ABS) help ensure secure stops.

In addition, the NSX's revolutionary variable electric power-assisted steering system provides excellent road feel and easy operation.

SUSPENSION
The desired goals for the NSX suspension went well beyond the typical goals of high lateral adhesion, transient response and linear response to control input. The engineers wanted a suspension that allowed the driver to easily control the car right to the limit, particularly with the more powerful 3.2-liter V-6 engine.

The basic configuration is similar to that of a Formula One car in that it employs an upper and lower control arm (or double-wishbone) design with a coil-over shock absorber and stabilizer bar front and rear. The rear suspension also has an additional transverse link for greater wheel control. All the suspension arms are made of extremely rigid and durable forged aluminum. The front steering and the rear hub carriers are also made from heat-treated aluminum castings. The springs are straight rate with an extended rubber bump stop mounted on the chassis which acts as a progressive springing element at the limit of wheel travel.

The shock absorbers are nitrogen-filled and feature a unique progressive valve design. The progressive opening of this valve produces a more favorable 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 front and rear suspension components are mounted on separate aluminum subframes using rubber bushings, designed to reduce vibration yet limit flex and shift of the suspension components relative to the subframes.

The suspension development program was far-ranging and took place at the Tochigi Proving Grounds, the Suzuka circuit, the 179-turn Nurburgring course in Germany, the Honda Proving Center of California (HPCC), and Honda's newest test track in Takasu, Hokkaido. In addition to the standard evaluations conducted in-house by the suspension engineers, the car was subjected to evaluation by top-rank drivers such as the late, three-time Formula One World Champion Ayrton Senna and Formula One driver Satoru Nakajima.

BRAKES
The NSX is equipped with 4-wheel ventilated disc brakes and dual-piston steel calipers. The diameter of the brake discs is 298 mm in the front and 303 mm in the rear. The combination of large rotors and flex-resistant dual-piston calipers allows the engineers to achieve the ideal braking system balance. The braking targets were to provide outstanding braking performance, excellent pedal feel, linear braking response and low pedal effort. Splash guards with cutouts aid in air ventilation and enhance fade resistance.

FOUR-CHANNEL ANTI-LOCK BRAKING SYSTEM (ABS)
The 4-channel Anti-Lock Braking System controls each wheel independently with a 16-bit microprocessor. This 4-wheel independent capability allows fine control of the anti-lock function especially when the car is braking on a surface with a split coefficient of friction-for instance, if the left side wheels are on snow, ice or standing water and the right side wheels are on dry pavement.

The basic configuration uses 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 VARIABLE POWER-ASSISTED STEERING SYSTEM
This power-assisted steering system was the first of its kind on the American market. The system consists of a rack-and-pinion steering gear with an electric motor installed concentrically around the steering rack. The steering system is a direct design which functions with no assist at higher vehicle speeds. A speed sensor in the electronic control unit determines road speed and, coupled with a new torque sensing system, feeds a signal to the motor. To ensure reliability, the electrical system for this unit features gold-plated connectors. All NSX models feature this electric power-assisted steering system.

FORGED ALLOY WHEELS
To reduce unsprung weight, and provide the highest strength possible, the engineers specified forged-aluminum alloy wheels. To enhance the look of the wheels, they have been machine finished, then clear-coated. The result is a very light wheel with the strength and impact resistance of a much heavier steel wheel. The rear wheels are 8.5 x 17 inches, and the front wheels are 7 x16 inches.

TIRES
The suspension engineers, working in conjunction with Yokohama Tire Company and Bridgestone Tire Company, sought to produce tires that would not only provide excellent traction and handling, but also allow the driver to "feel" the limits of the tires' performance.

The resulting uniquely designed tires were remarkable, meeting all the high-performance targets the engineers established early in the program.

The NSX is equipped with wide, low-aspect-ratio tires, front and rear, for more responsive handling and increased cornering capability. The tire sizes are 215/45 ZR16 front and 245/40 ZR17 rear. These tires provide excellent wet- and dry-weather traction, high-speed stability and immediate and predictable reaction to steering input.

1998 Acura NSX - Body

OVERVIEW
A rigid structure is of paramount importance in a performance car. High rigidity provides a stable platform for proper suspension geometry and alignment, and it makes possible a tight, rattle-free interior. Additionally, central to the goal of performance is a favorable power-to-weight ratio, which has been improved by 30 percent with the new 3.2-liter V-6. As a rule, a very light car can achieve high performance levels with less horsepower. After an intensive research effort, it was determined that the most efficient way to meet the rigidity and weight targets for the NSX was to build the car exclusively of aluminum.

Using a Cray supercomputer, the engineers performed millions of Finite Element Modeling (FEM) and stress analysis calculations. The result of this research and development effort is a chassis that weighs 210 Kg (462 lbs) with doors, hood and deck lids installed-about 40% 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 counter the small weight increase of the 6-speed transmission and larger brakes, key body parts are made with a newly developed 6000 series aluminum alloy that is up to 50 percent stronger, thus requiring less material to perform effectively. This thinner, lighter-weight material is used in making the doors, fenders, and front and rear deck lids, among other key parts of the NSX. For example, by using this high-strength alloy, thinner doorskin material netted a 2.2 kg (4.9 lbs.) weight reduction without any sacrifice in strength.

BODY REINFORCEMENTS
To maintain high rigidity in the body, even with the roof panel of the NSX-T removed, extensive reinforcement measures are employed throughout the body. Required reinforcement include side sill aluminum extrusion design that involves significantly thicker wall sections. Other areas include the base of the B-pillar where it joins the rocker panel, a larger rear bulkhead crossbar, a thicker trunk leading edge panel, a reinforcement web in the rear floor cross member, an additional rib in the center 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, and a redesigned front lower floor section with increased wall thickness.

REMOVABLE TOP
The removable top is made of aluminum for light weight and durability. The roof panel is body-colored and is easily removed by means of two latches located on the left and right side. Its light 8.5 kg makes it easy to remove and stow away. A dash indicator light alerts the driver if the latches are not properly closed. Once removed, the panel is stored under the rear glass hatch and the hatch can be locked with a key for security. Since the top has its own storage compartment, it doesn't use any of the available trunk or interior space. In addition, the vehicle security system functions with the top removed as well as in place.

EXTRUDED ALUMINUM SIDE SILLS
To attain a structure of high rigidity, complex aluminum extrusions were used for the crucial side sills of the unit body. These extrusions, with their carefully braced internal structure, contribute to the extremely high torsional stiffness of the NSX.

RADIUSED FRONT FRAME RAILS
To maximize occupant protection, the front frame rails of the unit body are designed with large-radius curves where they meet the passenger cabin. This design helps to dissipate energy in the event of a collision, spreading out impact loads and diverting them under the passenger cell.

1998 Acura NSX - Interior

CONCEPT AND GOALS
The objective was to create an interior that was the sports car equivalent of a jet fighter pilot's helmet. The key elements of this concept were unlimited visibility, a feeling of snugness or intimacy with the interior of the vehicle, and the sense that the cockpit and driver were out in the airstream rather than enclosed and isolated from the environment. To achieve this feeling, the seating space for the driver and passenger was designed to fit snugly at the hips and flow outward and upward to provide ample space for the head and shoulders.

SEATING POSITION AND VISIBILITY
A low seating position contributes to a low center of gravity and helps to reduce the frontal area for improved aerodynamics. Ordinarily, a low hip-point would impart to the driver the feeling of being buried in the interior and create a claustrophobic feeling. To avoid this, the body engineers created a very low cowl section which allowed them to lower the height of the dash and instrument panel. The low cowl also enhances forward visibility.

INSTRUMENTATION AND CONTROLS
In designing the instrument panel, the approach was one of simplicity. Since the primary function of the instruments is to relay information as clearly and quickly as possible, the designers opted for a traditional analog execution. The instrument faces are round with white numerals on a black background. The instrument panel is dominated by the tachometer on the left and the speedometer on the right. To the left of the tach are the smaller water temperature and oil pressure gauges. To the right of the speedometer are the fuel gauge and voltmeter.

All the major controls are clustered around the steering wheel column to make them easy to reach.

Additional features unique to the NSX-T include a dash light alerting the driver in the event the roof panel isn't fully latched and a locking mechanism for the roof panel storage compartment.

NSX-T WIND PROTECTION
The windshield header of the NSX-T has a special aerodynamic design that directs the airstream up and over the passenger compartment to minimize wind buffeting at speed. It's also equipped with smaller sun visors to enhance visibility.

The NSX also uses special, highly efficient heat-absorbing green glass to help keep the effects of solar loading on interior temperatures at a minimum in hot weather.

DUAL AIR BAG SUPPLEMENTAL RESTRAINT SYSTEM (SRS) WITH AUTOMATIC SEAT BELT TENSIONERS
The NSX is equipped with driver's and passenger's Supplemental Restraint System (SRS) air bags which are intended to supplement the seat belts. In conjunction with these, the NSX features automatic seat belt tensioners which use the same impact sensors as the air bags. The belt tensioners are activated simultaneously with the air bags, causing each belt to retract to help restrain the occupants in the event of a severe frontal collision.

LEATHER-TRIMMED UPHOLSTERY
Leather was a natural choice for the seat trim material; it is hand-stitched and hand-fitted to ensure quality craftsmanship and durability. The seat facings, door inserts, steering wheel and shift knob are covered with leather.

AUTOMATIC CLIMATE CONTROL SYSTEM
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. The system uses the environmentally friendlier R134A refrigerant.

ACURA/BOSE® MUSIC SYSTEM
Bose® engineers became involved with the NSX sound system at an early stage of interior design. This 4-speaker system was designed and calibrated specifically for the unique acoustics and resonances of the NSX interior and provides the highest quality imaging and spatial dynamics for both the driver and the passenger.

The Acura/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/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.

THEFT-DETERRENT SYSTEM
A sophisticated alarm system is standard equipment on the NSX. If an unauthorized attempt is made to enter or start the NSX, the horn sounds, the flashers are activated and the starter system is disabled. 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 operate even with the removable roof panel off the car.

SECURITY/IMMOBILIZER SYSTEM
A special, electronically coded key prevents the car from being started, even if a mechanical duplicate of the proper key shape is used. A transponder, built into the key, signals the immobilizer control unit that the key is genuine. If the car is hot-wired, or an unauthorized key is used, it simply will not start. This system is a substantial deterrent to theft. In New Jersey, for example, insurance premiums have been reduced as much as 15% when such a system is used.

1998 Acura NSX - Manufacturing

The central goal behind the design of the unique NSX assembly plant in Tochigi, Japan, is to produce the highest-quality automotive product in the world.

This plant has no automated conveyor line. Rather, each car is mounted on a dolly and pushed by hand from one workstation to the next. Each team of workers is responsible for the quality of work performed at their station. The car is not passed on to the next area until the team is satisfied that their procedures have achieved the tolerances and goals required in the specifications. Each assembly station, in effect, also functions as an inspection station.

Engine assembly is also done in a unique way to ensure the highest level of assembly quality. Contrary to typical mass production procedures, each NSX engine is assembled by an individual, highly skilled technician from start to finish. This process keeps tolerances to levels that would not be possible in a mass assembly procedure and helps assure reliability and durability.

PAINTING
The NSX is painted in a 23-step paint process, including an aircraft-type chromate coating designed for use with aluminum. A waterborne paint for the base coat was developed to achieve a clearer, more vivid color and a smoother surface finish.

1998 Acura NSX Specifications

April 24, 1997 — Torrance, Calif.