GT-R Technical Features PtII: Packaging

Such is the depth of information supplied on Nissan's all-new GT-R (and the interest in those details) we've taken the step of publishing a series of Technical Features spotlighting the GT-R. Here's the second -- Nissan's own overview of the GT-R's packaging

According to Nissan: the GT-R balances "power with practicability -- two contradicting factors -- to realise a new dimensional multiperformance supercar with ultimate performance for anyone, anywhere, anytime".

The brand summarises the packaging concept behind the new GT-R as follows: "Returning to the fundamental principle of what an automobile should be, the vehicle is designed to convert inertia force, generated by the earth's natural forces (gravity) and the vehicle in movement, into tyre grip, and change airflow into a stabilizing force."

To do so the GT-R adopts what the company has termed a "Premium Midship" package a further development of the FM (Front Midship) package pioneered in the latest incarnation of the 350Z. In addition, Nissan developed and patented a new system exclusively for the GT-R called 'Independent Transaxle 4WD'. This system sees the clutch, transmission and transfer case (for the all-wheel-drive system) moved to the rear of the vehicle and housed in a single housing that also incorporates the rear differential.

The engine remains at the pointy end and twin carbon-fibre prop shafts run, respectively, rearwards from the engine to the transaxle and from the transaxle forward to the front differential and drive componentry. Nissan claims this set-up is also a world first.

The company further claims the GT-R's unique set-up confers a number of advantages and outlines them as follows...

>> Stabilised ground loads
As speeds increase conventional vehicles have a tendency to lose front wheel adhesion from wind resistance (and lift). This is increased as the load shifts rearwards when drive force is applied. Front wheel lift results in lighter steering and Nissan asserts that in denser, wet conditions this can be exaggerated, leading to increased risk of hydroplaning.

According to Nissan, in part due to Independent Transaxle 4WD, the drive and weight distribution characteristics of the GT-R helps stabilize this load transfer and equalizes ground loads front to rear.

>> Optimised load distribution
Nissan says, typically, discussion on load distribution of conventional vehicles has been focused on static load conditions -- ie: when a car is parked. Nissan claims the GT-R's layout separates inertia load shift (with the engine load on the front tyres and transaxle load on the rear) to ensure "optimum balance and loading" when the vehicle is in use. Further, thanks to the transaxle's positioning (below the rear wheel centerline) the GT-R's centre of gravity is lower than a conventionally packaged vehicle.

The end result, the maker claims is "flat riding comfort with minimal load shift during braking, cornering and any driving situation."

>> Optimized Dimensions
The basic dimensions of the vehicle have also been optimised, according to Nissan. The concepts Nissan espouses regarding the balance of dimensions including tyre sizes, wheelbase versus centre of gravity height, front and rear weight distribution, etc, are illustrated in the 'Run', 'Turn' and 'Stop' diagrams shown hereabouts. [Note: in the diagrams Nissan compares the GT-R against German B, German P and USA C as well as the Z33 Fairlady. We can confirm the Z33 is better known Down Under as the 350Z. We're guessing you can work out the other cars.]

>> Fun-to-Drive Range Expanded
Says Nissan: "As load distribution is evenly balanced on all four wheels with the optimised load distribution and dimension, vehicle [the GT-R's] behavior is easy to grasp, allowing the driver to start accelerating earlier. In addition, powerful traction of the front wheels helps the vehicle to accurately accelerate in the steered direction. With this newly created 'traction steering' driving concept, the fun-to-drive range is widely expanded." [See also diagram hereabouts]
ATTENTION TO DETAIL
Nissan worked with Lotus Engineering in Europe and Japanese aerodynamicist and racecar designer, Yoshitaka Suzuka, to optimize the GT-R's aero package and detailing. The end result is what Nissan claims is "aerodynamic performance on a par with racing cars", combining a low drag coefficient (Cd: 0.27) and increased downforce.

The new Premium Midship package also balances aerodynamics and cooling, says the company. This is in part aided by the 'split' engine and transaxle.

According to Nissan, cooling air passes over the engine, enters the space where the gearbox/transfer case would normally be located, then flows along the floor tunnel to cool the transaxle. In addition to being more efficient, the underflow airflow "enables downforce air control under the floor, just as a racing car", says Nissan.

Wind noise has also been reduced, leading Nissan to claim: "This allows the driver to drive at 300km/h on the Autobahn and still enjoy conversation with the person in the passenger seat."

The final benefits claimed by Nissan for the GT-R's package relates to powertrain vibration characteristics and passenger cell dimensions. The separate engine and transaxle layout reduces vibration and also alters the harmonics of the assemblies. This reduces vibration and noise levels and increases drivetrain durability, according to Nissan.

The rear-mounted transaxle of the GT-R also frees-up foot space in the cabin to create "an optimized pedal layout" with special attention being paid to dimensions such as floor surface to hip point (200mm), pedal stroke length and steering wheel angle and reach, Nissan claims.