As Nissan racing car designers will tell you, the stiffer and lighter the bodyshell, the better the chassis behaviour. For the new R34 GT-R Nissan used a MRS (Multi Road Simulator) computer to help identify the optimum points for structural reinforcement. They then handed the car to the GT-R test team for final evaluation under real driving conditions on the track.
Meanwhile, the faster the speed, the greater the lift - it's a simple law of aerodynamics. This was the reason why the aerodynamicists spent so much time developing and honing the aerodynamic properties of the GT-R to maximise its stability at speed. On the underside a front diffuser and carbon-fibre rear diffuser work together to smooth the airflow under the car, reducing lift.
The rear spoiler counters lift when driving at high speed. To reduce the drag produced by the large fixed spoiler the GT-R used a lightweight aluminium alloy rear spoiler incorporating variable-angle rear wings. Their adjustability (max 30 deg, min 10 deg) allows four stages of downforce to be set, with minimal drag penalty.
The GT-R's twin-turbo 2,568cc straight-six engine is the heart of the R34 Skyline GT-R. Producing 280 PS @ 6,800 rpm the twin cam, four valves per cylinder unit was the ultimate development of the formidable engine used in the R33 version. Design improvement focused on the maximum driveability from lower rpm without compromising top end power. The new engine was lighter and delivered more torque with a quicker and smoother pick-u from lower rpm. The refinements in design had enabled Nissan to raise the rpm limit to 8,000 rpm.
Increased torque and reduced turbo lag was due the new Garrett turbochargers. These used ball bearings on the rotor shaft and ceramic rotors to reduce rotational friction by around 50%. Torque was increased further by using a new type of turbo compressor that reduced temperature build up to deliver a cooler, higher density charge to the engine. The end result was that the GT-R's maximum torque had risen to 40.0 kg @ 4,000 rpm.
To make best use of the engine's performance potential and raise the
GT-R's accelerative performance even further, Nissan worked closely with the German manufacturer GETRAG to develop a brand new 6-speed manual transmission. The gears were a close-ratio with a direct drive of 1:1 in 5th gear. The gear ratios make maximum use of the engine's wide torque spread, delivering punchy acceleration right up to 5th; 6th being an overdrive ratio that improved high speed cruising by reducing noise and fuel consumption levels. Despite the additional 6th gear the GETRAG transmission was about 3 kg lighter than the 5 speed unit fitted to the R33.
The best way to handle the power of an engine is to harness it to all four wheels, the R34 took the neutral handling of the rear wheel drive as its starting point and supplemented it with Nissan's ATTESA E-TS Pro, an electronically controlled 4WD torque split system. This put all drive through the rear wheels until the road conditions dictate that torque should be directed to the front. It slows the car to safely put maximum input into your driving with worrying about exceeding the cars capabilities.
The drive force distribution was continually monitored, varying between 100% rear drive and 50:50 front-to-rear (rigid 4WD). The proportional split is controlled by computer diagnosis of the driving situation relative to vehicle speed. Measurements are also taken from the throttle position, wheel speed sensors, and longitudinal and lateral G force sensors.
The computerised drive distribution programme prioritises handling and acceleration. If the rotational speed difference between the front and rear wheels increased, part of the torque from the rear wheels is sent to the front, countering yaw movement and increasing, allowing the GT-R to negotiate a corner with full driving force of 4WD.
Maximising stability under braking, in various road conditions, is achieved by placing the ABS within the control of the ATTESA computer.
The GT-R's LSD uses sensors to read the drivers input under varying road and driving conditions. Also, when corning, it limits the amount of inner wheel slippage to improve traction. Because the LSD and ATTESA E-TS Pro systems are fully integrated, they provide total control of the power delivery - both front-to-rear and left-to-right to the rear wheels.
By casting the lower front suspension arms from aluminium, Nissan chassis designers had reduced the GT-R's unsprung weight by 2.5 kg, improving mechanical grip in the process. The R34's suspension was a development of the multi-link system that was inherited from the legendary R32 GT-R. Nissan refined it to provide even more driver feedback by improving the rigidity of its attachment to the chassis. Nissan also improved the suspension geometry, and the rigidity of the front suspension member and rear suspension arms, to cope with the wider 245/40WR18 tyres.
The R34's steering provided more driver feel, giving easier control with greater feedback during the cornering and straight-line driving. We've also dramatically improved the performance of the shock absorbers under extreme low-speed conditions to reduce the rattle and 'jogging' created by minor irregularities in the road surface.
Maximum type grip was achieved by making a number of detail changes to the suspension design. Improving the hardness of the rubber bush on the rear suspension has enforced the camber rigidity. Nissan also adjusted the anti-roll bar to improve front-to-rear rigidity.
The GT-R's poise and precision under dynamic conditions owes much to Nissan's SUPER HICAS 4-wheel steering system. This adjusted the rear wheel angle in order to improve stability when corning, helping the car adhere to your chosen corning line. In the R34, Nissan developed adopted the 'Model Following Control System' (MFCS) to provide more sensitivity - it determines more accurately the correct angle of the rear wheels in relation to driving speed and steering position.
R34 uses the latest generations of SUPER HICAS with the Yaw-rate Feedback Control System (YFCS) inherited from the R33 GT-R. YFCS controls the rear wheel steering angle. Combined with MFCS, these two technologies provide more precise control over rear wheel angle and a more accurate response to driver input.
Hauling 1,666 kg of the GT-R from 160 mph down to 60 mph in the time to hit the apex puts masses of heat through the brakes, which is why the GT-R uses Brembo ventilated discs brakes for all four wheels. The
GT-R's system provided outstanding performance under race as well as road conditions. The brakes kept cooler through the characteristic diamond-shaped ventilation holes in the brake disc. Keeping the brakes cool maintains efficiency and eliminates brake fade under demanding conditions. The front brakes use four-piston aluminium calipers to spread their surface pressure better across the brake pad. The brake pads themselves use a high friction-coefficient brake compound made by Jurid of Germany.
The air intakes that gave such purposeful character to the GT-R's frontal appearance are purely functional. Quite apart from supplying a generous flow of cold air to the engine's radiator, oil cooler and intercooler, they also direct cooling air to the brakes. This is essential in fast circuit driving where the brakes are regularly overworked with pads, discs and brake fluid reaching extreme, performance-depleting temperatures. When this happens, the heat-dissipation effect of the ventilated brake discs becomes limited which is why further cooling is needed.
While the cooling air that flows in from the spoiler ducts is forced to the brakes, the surrounding wind is driven past the front skirt and spoiler, creating a counter flow of air between the wheels. The low pressure of the counting airflow sucks out the air that's been channelled at higher pressure through the brakes.
Nissan carried out repeated wind tunnel experiments to determine the best profile for the front skirt and spoiler. The final design was proven on the circuit where Nissan found the R34 could cool the brakes down by a further 50 degrees compared with the R33 GT-R.
High speed and tenacious grip amount to one thing - G force. The GT-R's potential for generating G-forces is extremely high for a road car, which is why the leather front seats are such a single minded, race proven design. Their heavily contoured profile provides comfortable support for long distance drivers, as well as all the lateral location necessary to prevent G-force from unseating you during cornering.
Nissan evolved the new GT-R seat from the acclaimed design used in the R33 by enlarging the shoulder and side supports. The side support is specially designed to ensure that it doesn't interfere with the steering or gear lever operation. Working with our test drivers, the eventual seat form was completed by fine tuning the thickness of the cushion, damping the hardness characteristics and improving the energy absorption for every part of the supporting padding.
The centre structure remains fundamentally unchanged from that used in the R33 - the shape used a moderately curved surface, made of high density cushion, to mould comfortably around the driver's body.
Especially for the UK market, Nissan (via Middlehurst Motorsport) had the GT-R seats upholstered in Connolly leather hide. The durability of leather makes it highly suitable for the well-contoured shape of the seat design. The leather upholstery extends to the rear seats and adds a luxurious aspect to the GT-R's function driven cockpit design.
Driving the GT-R anywhere near its limits demanded the use of a racetrack. There you can push yourself to the limit of your own abilities and revel in the feedback delivered not only by the chassis, but by the highest level of driver information available on a road car at that time. The GT-R's cockpit is equipped with an innovative, digital multi-function display which offered an instantaneous readout of all critical engines functions, and an accurate record of limits reached during a specific drive. It also had a number of specific facilities that are primarily for use on the race circuit - a lap timer, a G-force display and future capability for downloading data for post-race analysis.
Unlike other GT-R's, UK specification models were specially modified by Middlehurst Motorsport engineers to provide extra cooling for the engine, gearbox and 4WD transfer box. This ensures that prolonged periods of very high speed driving can be undertaken without the resulting high temperatures that might otherwise have occurred,
The engine had oil-to-air cooler mounted at the front of the car to maintain optimum oil temperature. The gearbox and transfer box each had their own dedicated oil pump and oil-to-air cooler. Both of these coolers where mounted behind the rear axle within the airflow stream channel beneath the car.