What makes Nissan GT-R so fast – technology explained
Nissan GT-R is the least expensive supercar you can get; the 2015 GT-R Premium Edition is listed at $101,770 which is a lot less than your average Ferrari or Lamborghini. The GT-R is a regular street-legal coupe with a V6 engine, yet it can accelerate from 0 to 60 mph in under 3 seconds, something that a very few other sports cars can do. Is there some secret technology? What makes Nissan GT-R so fast?
In a conventional rear-wheel drive sports car, like Chevrolet Camaro, Ford Mustang or Toyota Supra, the engine and transmission are placed in the front, but the engine torque is sent to the rear wheels. This means that no matter how powerful the engine is, the rear wheels will spin on hard acceleration. This happens because there is not enough weight pushing the rear wheels to the road, meaning the rear tires have less grip.
This is what Nissan engineers designing the GT-R took into account. The GT-R is all about the grip. How does it work? The GT-R has all-wheel drive, meaning the engine power is delivered to all four wheels. The engine is positioned in the front. The transmission, combined with the transfer case and a rear differential in one unit, is placed in the back. This gives the GT-R near perfect weight distribution 53/47 front to rear. What's more important, each wheel is pushed to the road with roughly the same weight.
How does the Nissan GT-R all-wheel drive system work?
Nissan GT-R all-wheel drive system is called ATTESA E-TS (Advanced Total Traction Engineering System for All-Terrain with Electronic Torque Split). Mechanically it's a fairly simple system; however, it involves very precise electronic control of the torque distribution. It's a rear-biased all-wheel drive system, meaning the rear wheels are always powered, receiving 50-100% of engine torque depending on the driving conditions. When needed, up to 50% of torque can be sent to the front wheels.
Let's look at the power flow in this diagram provided by Nissan: the engine torque is sent to the transaxle unit located at the back through the main carbon-composite propeller shaft (the larger shaft in the middle). The transaxle unit has a built-in transfer case, the device that splits the power between the front and rear axles. Click on the photo to see larger image.
The smaller additional propeller shaft sends the torque from the transfer case to the front differential. The front differential further splits torque between the left and right front wheels. The rear differential is built inside the transaxle unit. Similarly, the rear differential splits torque between the left and right rear wheels. The amount of torque sent to the front axle is controlled by the electronic control module using a multi-disc hydraulic clutch installed in the transfer case. The torque split between the front and rear axle varies depending on the road conditions. For example, under heavy acceleration, the torque is split close to 50:50 front to rear, but when coasting on a dry road at a steady speed, almost all power is sent to the rear wheels.
The front differential is an open type, meaning if the left wheel is spinning on the ice, very little torque will be mechanically sent to the right wheel. The rear differential is a multi-disc limited slip differential (LSD) where the slip between the rear wheels is limited. This means, if when taking off, one of the rear wheels is on the ice or snow, it won't spin freely; some amount of torque will be mechanically sent to the opposite rear wheel.
Nissan GT-R has a twin-turbo 3.8L V6 engine, model VR38DETT. Each engine is hand-assembled by a single technician – 'Takumi' or "master with greatest skill" in a clean room environment at the Nissan Yokohama engine plant. Starting from 2014, each engine bears a nameplate with the name of the engine builder. For a regular mass-production car, an engine is assembled on an assembly line, with different workers installing different parts because it's faster.
The VR38DETT engine uses some of the valve train components and basic design of the well-known VQ35 motor that has been used in many Nissan models such as the Altima, Maxima and Pathfinder. In the VQ engine, the cylinders are made of cast iron sleeves pressed into the aluminum block.
This is done to make the cylinder walls stronger to withstand up and down piston movement. To make the VR38 lighter, instead of heavy cast iron sleeves, a very thin layer (0.15 mm) of hard metal is applied to the cylinders using the plasma spray process. How the plasma spray process works: the stream of inert gas mixed with the powder of the coating material is heated using an electric arc and sprayed onto the cylinder walls.
As the weight distribution is very important, instead of opting for a heavier V8 or V10 engine, Nissan GT-R uses two high-performance IHI turbochargers (one at each side or 'bank') to get more power out of a smaller and lighter V6.
A turbocharger consists of two turbines (exhaust and intake) connected by one shaft; it works by using the energy of the fast exhaust gases exiting the engine to pump more air into the engine intake. When the car is accelerated, the exhaust-side turbine is spun by the exhaust gases, which in turn "spools" up the intake-side turbine. The intake-side turbine creates a boost and pushes the air into the engine under pressure. As the temperature of air entering the engine increases under pressure, two intercoolers are used to keep intake air cool and more dense. Pumping more air into the engine with turbochargers allows more fuel to be injected, which results in more power. The 3.8L V6 VR38 twin-turbo engine in the 2014 Nissan GT-R is rated at 545 horsepower at 6,400 rpm. Compare it to 429 horsepower of the 5.0L V8 in a 2013 Hyundai Genesis.
The VR38DETT has a twin-cam design (each cylinder head has two camshafts), with four valves per cylinder. A variable timing system is used on the intake side; the two bulging round covers in the front of the engine on the lower photo make space for the variable intake timing mechanism installed on the front ends of the intake cams. The intake camshafts are driven by a timing chain that is hidden behind the front engine cover. Similarly to the VQ engine, two smaller separate chains connect the intake and exhaust camshafts. The VR38DETT lubrication system is modified to withstand higher loads of high performance driving and requires fully synthetic oil: Mobil 1 0W-40 (100% synthetic) is specified oil for the 2013 Nissan GT-R. Similarly to most of cars with a turbocharger, the GT-R requires premium gasoline.
6-speed dual clutch automated manual transaxle
Nissan GT-R uses a 6-speed dual-clutch automated manual transmission produced by BorgWarner, which is essentially a manual transmission fully controlled by a computer. The transmission also has a 'Manual' mode, that allows the driver to shift the gears using the paddle shifters mounted on the steering wheel.
To understand how a dual-clutch automated manual transmission works, let's refresh how a regular manual transmission operates: you press the clutch, engage the first gear, then release the clutch; the steps are repeated with every shift. A dual-clutch automated manual transmission has two wet computer-controlled clutches (wet clutch means the friction plates are immersed in transmission fluid). One clutch controls odd gears (1,3,5); the other clutch controls even gears (2,4,6). When the car starts in the first gear, the second gear is already pre-shifted and as soon as the car reaches the speed suitable for the second gear, the odd-gear clutch disengages the first gear and almost simultaneously the even-gear clutch engages the second gear. Similarly, with the next 2-3 gear shift and so on. All this is done to minimize time and torque loss between gear shifting. According to Nissan, in the 2013 Nissan GT-R it takes only 0.15 seconds to change gears when in "R" mode.
Brakes, wheels and tires
Nissan GT-R uses Brembo six-piston brakes with full-floating vented and drilled two-piece rotors in the front. Six pistons means this yellow caliper in the photo has three pistons on each side of the rotor. Pistons are pushed out with hydraulic pressure to squeeze the rotors while braking. For comparison, a typical front-wheel drive car usually has only one piston on the inner side of the caliper.
The front rotors in the 2014 Nissan GT-R are 15.35 inches in diameter, much larger than in regular cars; for example, the front rotors in the 2013 Nissan Altima are only 11.7 inches in diameter.
The rear brakes in the GT-R have a similar design only with 4-piston calipers and smaller 15.0-inch full-floating two-piece rotors. 'Full-floating' means that the outer cross-drilled disc is connected to the inner part or 'hat' with a special hardware that allows some flex. This is helps to prevent warping, as the outer disc can expand separately from the 'hat' when heated.
In regular cars, the rotors are made from one piece of metal and because of this they tend to warp when heated during racing.
Nissan GT-R uses 20-inch run-flat tires with rear tires being wider than the front ones. The 20-inch tires were chosen because they offer an optimal road contact area for this vehicle. The wheel rims have knurling around the inside of the rim to keep the tires from slipping on the rim under heavy acceleration or braking.
What makes the Nissan GT-R so fast
To sum up, the most prominent technical feature of the Nissan GT-R is what Nissan calls Premium Midship platform with a rear-placed transaxle and a lighter, but powerful V6 engine in the front. Along with the all-wheel drive system, this creates a nearly perfectly-balanced performance machine with excellent handling and grip so that the driver feels in full control of the vehicle.
For this price range, Porsche 911 is probably the closest competitor; the 2013 Porsche 911 is priced from $82,000 to $172,000 depending on the model and can accelerate from 0 to 60 in 3.1 seconds. If you win the lottery or make it to the NHL, the 2014 Ferrari 458 Spider is listed only at $257,412, with the 0 to 60 time around 3 seconds. Compared to this, Lamborghini Gallardo is a steal: the 2014 Gallardo MSRP is 'only' $191,900. For those who prefer German Engineering, Audi R8 starts from $124,000. The R8 makes 0 to 60 mph in 3.3 seconds. And in case you invent the next Facebook or Instagram, for just $375,000, you can probably pre-order another Japanese supercar, Lexus LFA. All in all, folks, it looks like the "Godzilla" is the most affordable; the 2017 Nissan GT-R starts from $109,990, so keep making Youtube videos, maybe one day you will drive one.
Photo credits: Nissan, TestingAutos.