Technology

Technological Advances Achieved in the NSX-R


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Improved aerodynamics to significantly increase vehicle stability and cornering performance at high speeds

In order to endow the new NSX-R with outstanding high-speed performance, we turned our attention to aerodynamics and their effect on high-speed cornering power, braking, turn-in, and other aspects affecting vehicle controllability. This led us to a new technical approach called “aerodynamically-induced stability”. In addition to increasing high-speed cornering power, we have also striven to improve vehicle control quality – the ease with which the driver can control the car, and thus exploit its full potential. This enabled the chassis to be tuned for reduced understeer at low to medium speeds. The resultant improved handling at both low and high speeds endows the New NSX-R with outstanding speed on all types of circuits.

Fundamentals behind downforce and aerodynamic stability for improved high-speed vehicle handling

[ba-column size=”one-half” last=”0″]In order to endow the new NSX-R with outstanding high-speed performance, we turned our attention to aerodynamics and their effect on high-speed cornering power, braking, turn-in, and other aspects affecting vehicle controllability. This led us to a new technical approach called “aerodynamically-induced stability”. In addition to increasing high-speed cornering power, we have also striven to improve vehicle control quality – the ease with which the driver can control the car, and thus exploit its full potential. This enabled the chassis to be tuned for reduced understeer at low to medium speeds. The resultant improved handling at both low and high speeds endows the New NSX-R with outstanding speed on all types of circuits.

 

Relationship between vertical force and cornering force
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As the vertical force applied to the tire increases, cornering force also increases. In other words, increasing the vertical force applied to the tire has the same effect as using larger tires.

[/ba-column][ba-column size=”one-half” last=”1″]The third advantage of downforce is that it helps reduce body roll as well as body pitch. This in turn helps reduce sudden variations in vertical forces applied to the tires at the limit, increasing vehicle stability in the wake of driver input. Vehicle behavior is also more linear near the limit of adhesion, contributing to increased driver control. In other words, creating downforce to press the vehicle onto the road as speed increases not only contributes to increased absolute cornering speed and thus absolute dynamic performance, but also significantly improves vehicle control quality as measured by response to driver inputs and vehicle stability at the limit. These are the fundamentals behind downforce and aerodynamic stability as a means to improved high-speed vehicle handling.

 

How downforce helps control changes in attitude
Downforce helps reduce body roll while cornering and body pitch during braking or acceleration. This also helps reduce sudden variations in vertical forces applied to the tires at the limit, for increased vehicle stability. Downforce not only increases dynamic performance, but also creates a more stable vehicle behavior environment for steering, throttle, and braking inputs.

Downforce helps reduce body roll while cornering and body pitch during braking or acceleration. This also helps reduce sudden variations in vertical forces applied to the tires at the limit, for increased vehicle stability. Downforce not only increases dynamic performance, but also creates a more stable vehicle behavior environment for steering, throttle, and braking inputs.

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Extensive circuit testing to determine the optimum equilibrium between downforce and front-to-rear balance

[ba-column size=”one-half” last=”0″]In order to endow the new NSX-R with outstanding high-speed performance, we turned our attention to aerodynamics and their effect on high-speed cornering power, braking, turn-in, and other aspects affecting vehicle controllability. This led us to a new technical approach called “aerodynamically-induced stability”. In addition to increasing high-speed cornering power, we have also striven to improve vehicle control quality – the ease with which the driver can control the car, and thus exploit its full potential. This enabled the chassis to be tuned for reduced understeer at low to medium speeds. The resultant improved handling at both low and high speeds endows the New NSX-R with outstanding speed on all types of circuits.

 

Downforce balance front to rear (Straight-line driving at constant speed)
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By creating a downforce with the same front-to-rear balance as vehicle weight, changes in steering characteristics from low to high speeds remain well under control. At higher speeds this translates into a more linear response. More precise control of the vehicle helps the driver delve further into the car’s potential.

[/ba-column][ba-column size=”one-half” last=”1″]The third advantage of downforce is that it helps reduce body roll as well as body pitch. This in turn helps reduce sudden variations in vertical forces applied to the tires at the limit, increasing vehicle stability in the wake of driver input. Vehicle behavior is also more linear near the limit of adhesion, contributing to increased driver control. In other words, creating downforce to press the vehicle onto the road as speed increases not only contributes to increased absolute cornering speed and thus absolute dynamic performance, but also significantly improves vehicle control quality as measured by response to driver inputs and vehicle stability at the limit. These are the fundamentals behind downforce and aerodynamic stability as a means to improved high-speed vehicle handling.

 

Testing at Honda's proving grounds in Takasu, Hokkaido

Testing at Honda’s proving grounds in Takasu, Hokkaido

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A front hood air duct: the aerodynamic mechanism for creating downforce

At the rear, downforce is easily obtained using a wing-type spoiler. At the front, though, adding too big an aerodynamic device can negatively affect minimum ground clearance and/or the approach angle. Increased aerodynamic resistance resulting in reduced acceleration is also another example of the many problems associated with obtaining appropriate downforce in a road-going car. The solution we chose was to design the underbody of the car as flat as possible to encourage smooth airflow under the car, maintaining airflow speed to create downforce. This method not only provides for adequate ground clearance and approach angle but also does not unduly increase the forward-protruding surface of the body. However, this led to a new problem: how to extract the airflow through the front radiator that had previously been channeled underneath the car? Taking advantage of the car’s mid-ship layout, an air duct was added in the front hood to provide the necessary extraction route. Longitudinal fins were also added to the outer left and right sides of the front under-cover tray to prevent the air passing under the car from entering the front wheel wells. Similarly, spats have been added to both sides of the air ducts to channel air passing through the ducts away from the wheel wells. The opening ratio under the front bumper has also been reduced to limit as much as possible the actual amount of air flowing through. All these innovations result in a smoother airflow both under the body and through the front hood, achieving the desired downforce. No large aerodynamic appendage was required, helping maintain the original NSX’s overall design and ensure a relatively low aerodynamic drag. Downforce was thus achieved without sacrificing top speed. Wind tunnel tests have shown that when the car is at an angle relative to wind direction, the longitudinal fins of the front under-cover tray function in the same way as the chin spoiler, effectively reducing body lift and improving transient characteristics. [ba-column size=”one-half” last=”0″]

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Wind tunnel testing

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View of the underbody

[/ba-column] [ba-box background=”#FFFFFF” border=”#CC0000″][ba-column size=”one-half” last=”0″] Cd (Drag coefficient): 0.32 Cl (Lift coefficient/overall): -0.100 Clf (Lift coefficient/ front): -0.040 Clr (Lift coefficient/rear): -0.060 Compared to the original NSX-R, this translates into an increase in vertical force acting on the front tires of 36.2kgf, and of 25.0kgf on the rear tires (test results measured at 180 km/h in both cases).[/ba-column] [ba-column size=”one-half” last=”1″] Lift reduction measures (effect measured piece-by-piece) t3_03 [/ba-column][/ba-box] [ba-box background=”#FFFFFF” border=”#CC0000″]

Extensive circuit testing to determine the optimumequilibrium between downforce and front-to-rear balance

[ba-column size=”two-thirds” last=”0″] The air duct in the front hood could have been made simply by cutting an opening and trimming the edges with plastic. But because we wanted to maintain the beauty of the original design including the simplicity of line worthy of a car cut for speed like the NSX-R, and to reach the weight reduction target we had set for ourselves, we chose carbon fiber instead. The rear spoiler is similarly a single piece of carbon fiber designed to achieve the required downforce while maintaining a low drag coefficient in a simple shape embodying functionality and beauty.Both parts are formed using an autoclave, a method more often seen in aircraft manufacture. Multiple layers of pre-pregs made of resin-impregnated carbon fibers are cured in a high-pressure oven to form the parts. The front hood is made of carbon Aramid fibers for added resistance to tearing. In the event of an accident, it is designed not to shatter into small pieces. During the laminating process, fibers are offset by 45 degrees, with each layer above and below being symmetrically angled to provide equal strength in all directions.Nine to ten hours are required to complete the laminating process of each single part. After lamination, the whole lay-up is wrapped in a baking film, and a vacuum is applied to consolidate the laminate prior to curing for 2-3 hours in the autoclave at a pressure of two to three atmospheres. Once in the autoclave, it takes one hour to bring the part to temperature, while some five hours are required for the cooling down process. Air released from the resin when liquefying at high temperature is carefully bled off to form a strong CFRP (Carbon-Fiber Reinforced Plastic).The front hood’s outer skin is formed separately from the inner frame before being glued together. Glue thickness is strictly maintained at less than 0.5mm. The resultant strength is superior to that of the base materials. The rear spoiler is a hollow, one-piece molding made using a proprietary process developed in cooperation with a parts supplier.Durability, a matter not normally emphasized in aerodynamic carbon fiber parts manufacture, has been pursued to the utmost. In all aspects of the product, durability on par with steel is achieved. The painting process has also been the object of painstaking attention, especially regarding the undercoating, with both parts undergoing a “5 coat/5 bake” process. For the front hood in particular, paint has been applied so as to let the roughness of the carbon fiber surface show through ever so slightly. t3_06[/ba-column] [ba-column size=”one-third” last=”1″] t3_04 t3_05 [/ba-column][/ba-box] [ba-column size=”one-half” last=”0″] In order to endow the new NSX-R with outstanding high-speed performance, we turned our attention to aerodynamics and their effect on high-speed cornering power, braking, turn-in, and other aspects affecting vehicle controllability. This led us to a new technical approach called “aerodynamically-induced stability”. In addition to increasing high-speed cornering power, we have also striven to improve vehicle control quality – the ease with which the driver can control the car, and thus exploit its full potential. This enabled the chassis to be tuned for reduced understeer at low to medium speeds. The resultant improved handling at both low and high speeds endows the New NSX-R with outstanding speed on all types of circuits.[/ba-column] [ba-column size=”one-half” last=”1″] The third advantage of downforce is that it helps reduce body roll as well as body pitch. This in turn helps reduce sudden variations in vertical forces applied to the tires at the limit, increasing vehicle stability in the wake of driver input. Vehicle behavior is also more linear near the limit of adhesion, contributing to increased driver control. In other words, creating downforce to press the vehicle onto the road as speed increases not only contributes to increased absolute cornering speed and thus absolute dynamic performance, but also significantly improves vehicle control quality as measured by response to driver inputs and vehicle stability at the limit. These are the fundamentals behind downforce and aerodynamic stability as a means to improved high-speed vehicle handling.[/ba-column] [ba-column size=”one-half” last=”0″]
Downforce balance front to rear (Straight-line driving at constant speed)
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By creating a downforce with the same front-to-rear balance as vehicle weight, changes in steering characteristics from low to high speeds remain well under control. At higher speeds this translates into a more linear response. More precise control of the vehicle helps the driver delve further into the car’s potential.

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Testing at Honda's proving grounds in Takasu, Hokkaido

Testing at Honda’s proving grounds in Takasu, Hokkaido

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Outstanding cornering speeds achieved under all conditions from high to low speeds

For ultimate speed on the circuit, a specially designed tire with an asymmetrical tread pattern was selected. At the same time, roll rigidity, performance envelope and response were all increased in the pursuit of further improved cornering speeds. The newly gained aerodynamic stability leads to improved high-speed stability, allowing the understeer setting previously adopted for low to medium cornering speeds to be reduced. Front turn-in response has also been increased toward a more controllable setting for the driver. To supplement the added speed, braking capacity has also been increased, particularly in the area of fade resistance on circuit runs. The anti-lock brake system has also been fine-tuned for even greater stability when braking hard at high speeds.

Combining high-speed stability with low-speed cornering performance
[ba-column size=”one-half” last=”0″]By contributing to increased high-speed stability, the aerodynamically induced downforce achieved in the New NSX-R has allowed the selection of a harder suspension setting to further increase cornering performance and overall dynamic performance. Overall, the suspension is tuned to promote higher cornering limits and improved handling response. The first issue we addressed was roll rigidity, equipping the NSX-R with heavier-duty springs, new spring material for reduced weight, increased damping rates, larger stabilizer bars, reinforced damper mount and rear control arm bushings for a sharper, more responsive drive. The stabilizer bar bushing is now self-lubricating for increased rigidity, enhancing the stabilizer bar’s effect. Compared to the rear, the front suspension is tuned to increase road holding. Reduced understeer contributes to improved cornering behavior around tight bends, while t4_01[/ba-column] [ba-column size=”one-half” last=”1″]aerodynamically-improved stability delivers superior performance at higher speeds, for further enhanced performance under all circuit conditions. LSD (limited-slip differential) pre-loading has been tuned to take into account the increased cornering performance provided by aerodynamic downforce, for improved traction. Body rigidity has also been fine-tuned, with the adoption once again of front and rear tower bars. Although the front tower bar is the same as that of the original NSX-R, the rear one has been thickened from t1.0mm to t2.3mm over the original setting, for increased rear roll rigidity. The dampers have also seen their damping rate increased, although particular attention has been paid this time to damping characteristics for minor inputs at very low speeds, with the objective of further smoothing out minor vibrations. The pistons used in the dampers are now polished to minimize production tolerances and reduce differences from damper to damper. t4_02[/ba-column] [ba-column size=”one-half” last=”0″]
Extensive circuit testing to determine the optimum equilibrium between downforce and front-to-rear balance

In order to endow the new NSX-R with outstanding high-speed performance, we turned our attention to aerodynamics and their effect on high-speed cornering power, braking, turn-in, and other aspects affecting vehicle controllability. This led us to a new technical approach called “aerodynamically-induced stability”. In addition to increasing high-speed cornering power, we have also striven to improve vehicle control quality – the ease with which the driver can control the car, and thus exploit its full potential. This enabled the chassis to be tuned for reduced understeer at low to medium speeds. The resultant improved handling at both low and high speeds endows the New NSX-R with outstanding speed on all types of circuits.

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Custom designed tires and forged aluminum wheels

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Extensive circuit testing to determine the optimum equilibrium between downforce and front-to-rear balance

The third advantage of downforce is that it helps reduce body roll as well as body pitch. This in turn helps reduce sudden variations in vertical forces applied to the tires at the limit, increasing vehicle stability in the wake of driver input. Vehicle behavior is also more linear near the limit of adhesion, contributing to increased driver control. In other words, creating downforce to press the vehicle onto the road as speed increases not only contributes to increased absolute cornering speed and thus absolute dynamic performance, but also significantly improves vehicle control quality as measured by response to driver inputs and vehicle stability at the limit. These are the fundamentals behind downforce and aerodynamic stability as a means to improved high-speed vehicle handling.

Slit-surfaced brake rotors

Slit-surfaced brake rotors

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Further-honed engine response Even more linear throttle response

In addition to aerodynamically-induced stability, the ultimate in vehicle control calls for further detailed tuning to bring man and machine even closer together. Drawing upon know-how acquired through racing at Le Mans and in the Japanese GT Championship, time-consuming high precision production methods have been adopted to create an even better engine feel. We also worked to improve the feeling of linearity between throttle operation and the resultant variation in torque output.

Blueprinting and balancing of the crankcase assembly for engine feel and response that will set your heart pounding
[ba-column size=”two-thirds” last=”0″]The engine employs the same kind of high precision dynamic balanced clutch cover, fly wheel, and pulley assembly as is used in racing engines. Highly qualified veteran technicians check each assembly with a balancer, pruning away tiny specks of metal with their high precision drill. Rotating weight tolerance is reduced to below 1/10 that of the base NSX, to correspond to the same exacting standards used in racing. To obtain the maximum effect of this high-precision balancing, weight tolerances of the piston and connecting rod pairs are controlled to within about half that of the base model, just as in the original NSX-R. Crankcase-side and engine block-side main journal diameters are measured, and those having the same bearing metal thickness are combined to increase metal clearance precision and reduce friction. The adoption of these and other time-consuming methods normally unheard of in mass-production imbue the New NSX-R’s engine with breathtaking response and feel.[/ba-column] [ba-column size=”one-third” last=”1″]
Measuring the dynamic balance of the crankshaft assembly

Measuring the dynamic balance of the crankshaft assembly

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Drive By Wire system and accelerator pedal stroke circuit-tuned, for improved throttle response

Circuit testing has been extensively employed to tune throttle linearity and response as part of the ongoing effort to improve vehicle control quality. The electronically-controlled Drive by Wire (DBW) throttle has been tuned to reach full throttle at a pedal angle reduced from the previous 81 degrees to 68 degrees, resulting in an accelerator pedal stroke reduction of some 8mm. At the same time, pedal control has been tuned for increased pedal weight. The result is a more solid pedal feel with a more instantaneous, direct throttle response. Even if the driver’s foot is jarred by outside forces on the circuit, the system has been tuned not to drastically change the throttle angle. The final drive gear ratio has been lowered by 4.1% and combined to a close-ratio 6-speed gearbox for sharper engine pick-up and exhilarating throttle response. (All figures relative to base model.) [ba-column size=”one-half” last=”0″]

DBW tuning characteristics

DBW tuning characteristics

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Accelerator pedal weight characteristics

Accelerator pedal weight characteristics

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Highly functional accoutrements further improve ease of operation for increased speed and driving pleasure

The relentless pursuit of vehicle control quality in the New NSX-R extends to all cockpit parts within the driver’s reach. No matter how high the car’s dynamic performance has been raised, if precise operation is not possible its potential can not be fully realized. Items like the ball-shaped shift knob offer superior fit and contribute toward a new approach in vehicle control quality throughout a wide range of driver positions.

Titanium ball-shaped shift knob suits a wide range of driving styles

Shift knob shape was tested on the circuit, resulting in the selection of a ball-shaped design for its superior operating feel and adaptability to a wide range of driving styles. The knob is sculpted from pure titanium for a simple, sturdy feel. Such is the attention to detail that, when hand carving the yellow shift pattern, we polished the edges down so that the driver would not be distracted by the feel of the numbering while griping the knob. The shift knob is also complemented by a lightweight mesh jersey boot that matches the new interior design. Weight reduction is pursued right down to this level of detail.

Shift indicator uses green and red flashing lights to inform the driver of proper up-shift timing

The shift indicator uses green and red lights which flash then light up to indicate the power peak and rev limit, respectively, promoting more precise up-shifting and a more exhilarating driving experience. Standard power peak is 7,100rpm and standard rev limit 7,700rpm, with each light set to flash and then light up as the standard value is reached. The standard rev limit for first and second gears, however, is set 200rpm lower. Operating parameters require that the transmission be in gear and the throttle open 17° or wider. Control of the lights ‘flashing and lighting up is carried out by the engine’s ECU. Operating parameters are set for circuit or other spirited driving conditions. The gauges employ yellow needles unique to the new NSX-R, with a red ring around the outside for an exhilarating design befitting a car built for speed. The orange numbering on the dials is illuminated for a unified look day and night.

Seats upholstered in perforated suede with mesh jersey side supports, for improved hold

The full-bucket Recaro seats employ a carbon Aramid shell for superior hold and weight reduction. The side supports are upholstered in light, breathable mesh jersey, with the seat and seat back covered in perforated lux suede, for reduced sliding of the driver’s racing suite during high-G conditions. This seat was selected to help the driver perform to his maximum potential on the race circuit.

A small-diameter, leather-wrapped Momo steering wheel and other high-performance cockpit accoutrements

The 360mm small-diameter leather-wrapped Momo steering wheel* helps the driver respond quickly. Other features include side panels and shift plates made from real carbon fiber, an instrument panel made of high-matt rubber to minimize reflective glare on the front windshield, and aluminum pedals available through the Custom Order Plan.

 In cars equipped with the manufacturer's optional dual SRS airbags, only the leather-wrapped portion is made by Momo.

In cars equipped with the manufacturer’s optional dual SRS airbags, only the leather-wrapped portion is made by Momo.

 

Weight reduction down to the last gram, for more nimble performance

Weight reduction was one of the major themes in the creation of the NSX, as is evidenced by its all-aluminum body and other features. Over the years, and throughout the NSX’s performance evolution, we have continued to pursue further weight reduction for enhanced driving performance. The design of the new NSX-R incorporates weight reduction technologies achieved through the evolution of the new-generation base model, as well as inheriting those innovations initiated in the first-generation NSX-R. Challenging ourselves to even further weight reduction, this time around we have employed ultra-lightweight carbon fiber materials. The rear partition glass has also been made thinner and high-matt rubber employed in the instrument panel, for painstaking weight reduction right down to the last gram.

Years of experimentation and the introduction of new carbon fiber materials, combined with the determination to shave off excess weight wherever it could be found, resulted in a vehicle weight of just 1,270kg*

Throughout the NSX’s many years of evolution, we have continued to pursue further weight reduction as a vital factor in sports car performance. Performance improvements such as the adoption of a 3.2-liter engine for higher output, a 6-speed manual transmission, wider tires and wheels, along with emissions reduction and other environmental and safety measures, led to unavoidable weight gains. Countermeasures were taken, though, resulting in a 2002 base model that boasts a vehicle weight 10kg less than that of the debut model. And now the new NSX-R has achieved further major weight reduction, despite the added weight of its aerodynamic parts. Innovations include special custom lightening for the NSX-R, along with the use of new ultra-light carbon fiber materials. A carbon fiber hood results in a 2.20kg saving, while the carbon fiber rear spoiler saves 1.30kg. Furthermore, thinner rear partition glass saves 0.20kg, the high-matt rubber instrument panel 0.62kg, the mesh jersey shift boot 0.01kg, for painstaking weight reduction right down to the last gram. The result: a vehicle weight of just 1,270kg. The spare tire was also removed**, holding outfitted weight down to a mere 1,274kg. * Vehicle weight as officially registered. ** Equipped with aerosol-type puncture kit. Spare tire can be ordered separately through automotive dealers. Weight reduction of the new NSX-R achieved through years of accumulated know-how and new innovations. t7_01

Major Equipment

  Major equipment

Specifications



Specifications

NSX Type R, tri-perspective diagram (units: mm)



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