ATTESA (acronym for Advanced Total Traction Engineering System for All-Terrain) is a

four-wheel drive A four-wheel drive, also called 4×4 ("four by four") or 4WD, is a two-axled vehicle drivetrain capable of providing torque to all of its wheels simultaneously. It may be full-time or on-demand, and is typically linked via a transfer case pr ...

system used in some

automobiles A car, or an automobile, is a motor vehicle with wheels. Most definitions of cars state that they run primarily on roads, Car seat, seat one to eight people, have four wheels, and mainly transport private transport#Personal transport, peopl ...

produced by the Japanese automaker

Nissan is a Japanese multinational Automotive industry, automobile manufacturer headquartered in Yokohama, Kanagawa, Japan. The company sells its vehicles under the ''Nissan'' and ''Infiniti'' brands, and formerly the ''Datsun'' brand, with in-house ...

, including some models under its luxury marque

Infiniti (stylized in all caps) is the luxury vehicle division of the Japanese automaker Nissan. The brand began on November 8, 1989, initially in North America. The marketing network for Infiniti vehicles included dealers in over 50 countries in the 201 ...

. The 'mechanical' ATTESA system was developed for

transverse Transverse may refer to: *Transverse engine, an engine in which the crankshaft is oriented side-to-side relative to the wheels of the vehicle *Transverse flute, a flute that is held horizontally * Transverse force (or ''Euler force''), the tangen ...

, or front-wheel-drive vehicles and was first introduced with the RNU12 Bluebird in the Japanese market, entering production in September 1987. The system ran right throughout the U12 series (RNU12/HNU12) and was fitted to numerous U12 models with differing engine and transmission combinations. An almost identical system is fitted to the RNN14 GTi-R

Pulsar A pulsar (''pulsating star, on the model of quasar'') is a highly magnetized rotating neutron star that emits beams of electromagnetic radiation out of its Poles of astronomical bodies#Magnetic poles, magnetic poles. This radiation can be obse ...

and the HNU13 Bluebird and the HNP10 Primera, finding usage in numerous other Nissan models. Quite similar to offerings from other manufacturers, drive passes from the gearbox to a center

viscous Viscosity is a measure of a fluid's rate-dependent resistance to a change in shape or to movement of its neighboring portions relative to one another. For liquids, it corresponds to the informal concept of ''thickness''; for example, syrup h ...

limited slip differential A limited-slip differential (LSD) is a type of differential gear train that allows its two output shafts to rotate at different speeds but limits the maximum difference between the two shafts. Limited-slip differentials are often known by the ...

, into a transfer case splitting drive to a co-located front differential, and tail shaft connected to the vehicle's rear differential. From 2000 model year onwards, the system received an update where, as with a typical FWD car, the

transaxle A transaxle is single mechanical device which combines the functions of an automobile's transmission (mechanics), transmission, axle, and differential (mechanics), differential into one integrated assembly. It can be produced in both manual tra ...

now contained a differential that drives the front wheels. However, an extra shaft from this differential also drives a bevel gear housed in the transfer case that permanently turns a

driveshaft A drive shaft, driveshaft, driving shaft, tailshaft (Australian English), propeller shaft (prop shaft), or Cardan shaft (after Girolamo Cardano) is a component for transmitting mechanical power, torque, and rotation, usually used to connect ...

for the rear wheels (i.e. there is no longer a "center" differential). Housed in the rear differential is a viscous coupling that in normal conditions is disengaged. This means that for general driving, the system is FWD only. When the computer detects slippage of the front wheels, the viscous coupling engages and transfers up to 50% of the torque to the rear wheels. This system is superior in some aspects since the standard operation is FWD there is less power lost due to friction. However, it is no longer a full-time 4WD system, and since the coupling is in the rear differential, the driveshaft itself is constantly driven even though it is not connected to anything, which saps some power and efficiency (the analogue being the front driveshaft of a part-time 4x4 truck without locking hubs).

Variations

E-TS

The Electronic Torque Split version of this all-wheel drive architecture is a more advanced system developed for Nissan vehicles with a longitudinal drive train layout. It was first used in August 1989 in the R32 Nissan Skyline GT-R and Nissan Skyline GTS-4. Although the Skyline GT-R is exclusively AWD with manual transmission, ATTESA E-TS is also used in Nissan models that are available as rear wheel drive (RWD) with automatic transmissions fitted, such as the A31 Nissan Cefiro which was the second Nissan to feature the system exactly a year later in August 1990, and vehicles based on the

Nissan FM platform The Nissan FM platform is a Front-engine, rear-wheel-drive layout, FR automobile layout. The name is derived from the "mid-engine design, front midships" location of the engine, with its center of mass located behind the front axle centerline, shi ...

(which are sold in certain markets under the

luxury brand). The ATTESA E-TS version uses a mostly conventional RWD transmission. Drive to the rear wheels is constant via a tailshaft and rear differential, but drive to the front wheels is more complex by utilizing a

transfer case A transfer case is an intermediate gearbox that transfers power from the transmission of a motor vehicle to the driven axles of four-wheel-drive, all-wheel-drive, and other multi-axled on- and off-road machines. A part of the vehicle's drivetr ...

on the rear of the transmission. Front-to-rear torque split can go from 0:100 during acceleration to a maximum of 50:50. The drive for the front wheels comes from a transfer case bolted on the end of an almost traditional Nissan RWD transmission. A short driveshaft for the front wheels exits the transfer case on the right side. Inside the transfer case a multi-row chain drives a multi-plate wet clutch pack. Drive from the chain is apportioned using this

clutch A clutch is a mechanical device that allows an output shaft to be disconnected from a rotating input shaft. The clutch's input shaft is typically attached to a motor, while the clutch's output shaft is connected to the mechanism that does th ...

pack in the transfer case "differential" (the system thus does not involve a regular gear differential as in a full-time 4WD layout, but rather a center clutch), similar to the type employed in the Steyr-Daimler-Puch system in the Porsche 959. This unit is lubricated with its own dedicated NS-ATF fluid supply (Nissan Special Automatic Transmission Fluid) and is not in any way connected to the fluid in the transmission. Some Nissan models have an external cooler with an electric pump to cool this fluid. Situated on top of the rear differential is a high pressure, low volume electric pump. This pump pressurizes Normal ATF (0-288 psi) into the transfer case to engage the clutch pack. This fluid only engages the clutch pack and does not mix with the NS-ATF lubricating the transfer case. The higher the fluid pressure the transfer case is supplied with from the pump, the more the clutch pack engages, enabling the torque to the front wheels to be varied. Exiting the transfer case, the front drive shaft runs along the right side of the transmission, into a differential located on the right of the engines sump. This is a cast aluminum unit, with the sump and front differential made as a single unit that cannot be separated. The front right axle is shorter than the left, because the differential is closer to the right wheel. The front left axle runs through the engine's sump to the left wheel. To control the ATTESA E-TS system, there is a 16-bit computer that monitors the cars movements 10 times per second to sense traction loss by measuring the speed of each wheel via the ABS sensors. Also a three-axis G-Sensor mounted underneath the center console feeds lateral and longitudinal inputs into a computer, which controls both the ATTESA-ETS AWD system and the ABS system. The computer can then direct up to 50% of the power to the front wheels. When slip is detected on one of the rear wheels (a rear wheel turn 5% or more than the front wheels), the system directs torque to the front wheels which run a non-limited slip differential. Rather than locking the AWD in all the time or having a system that is "all or nothing", the ATTESA E-TS system can apportion different

torque In physics and mechanics, torque is the rotational analogue of linear force. It is also referred to as the moment of force (also abbreviated to moment). The symbol for torque is typically \boldsymbol\tau, the lowercase Greek letter ''tau''. Wh ...

ratios to the front wheels as it sees fit. This provides the driver with an AWD vehicle that performs like a rear wheel drive vehicle in perfect conditions and can recover control when conditions aren't as perfect. From the factory, the system is set up to provide slight oversteer in handling, and in fact the harder the car is cornered, the LESS the AWD system engages the front wheels. This promotes the oversteer rather than understeer which is apparent in most AWD/4WD vehicles. The advantage to a more traditional ATTESA ( viscous LSD) system is response in hundredths of a second. Some models fitted with the ATTESA E-TS system (such as the Nissan RS4 Stagea) have an "S" button on the dash. This will bypass the control system of the ATTESA E-TS computer and lock the transfer case into full 4WD. This is to be used at low speeds in snowy/icy conditions only as understeer is greatly increased in this mode.

E-TS Pro

In 1995, with the introduction of the R33 Skyline GT-R, Nissan introduced a new version of their ATTESA system. It was named ATTESA-ETS Pro, as an upgrade from the earlier ATTESA-ETS. It was standard equipment in the R33 & R34 Skyline GT-R V.spec (Victory Specification) model, and was offered as an option on the standard Skyline GT-R models called the "Active

LSD Lysergic acid diethylamide, commonly known as LSD (from German ; often referred to as acid or lucy), is a semisynthetic, hallucinogenic compound derived from ergot, known for its powerful psychological effects and serotonergic activity. I ...

option". The active rear

was also available as an option on some rear wheel drive Nissans such as the R33 GTS25t, the C34 RS Stagea and Y33 Cima S-Four.. ATTESA E-TS Pro differs from the standard ATTESA E-TS in a few ways. Where ATTESA E-TS controls the front to rear torque-split, the Pro system is also capable of left-and-right torque split to the rear wheels. This is done via an active rear

. Additionally, ATTESA E-TS Pro was marketed as controlling the ABS system to each wheel independently, while the previous ABS computer could sense the speed of each wheel its ABS pump is only 3-channel (both rear brakes are linked as a pair). Although this is not part of the AWD system, the computer makes use of the same sensors to determine wheel slip and traction. On ATTESA E-TS Pro equipped vehicles, the front differential remains a standard differential, not being linked to the ATTESA E-TS Pro system. The R33 Skyline regularly updates the speed of the rear wheels to the wheel speed sensors 100 times per second while the R34 Skyline regularly updates the speed of the rear wheels to the wheel sensors 1,000 times per second. The 2009

Nissan GT-R The Nissan GT-R (''Gran Turismo–Racing''; model code: R35; Japanese: 日産・GT-R; ''Nissan GT-R'') is a series of cars built by Japanese marque Nissan from 2007 to 2025. It has a 2+2 (car body style), 2+2 seating layout and is considered b ...

uses an updated version of the ATTESA E-TS, which is designed to work with the car's rear transaxle layout. The system is unique in the way that it utilizes two driveshafts under the vehicle's centerline, with a second driveshaft running slightly to the right of the main driveshaft which transfers power to the front wheels. Unlike the previous ATTESA systems which relied heavily on mechanical feedback, the system in the GT-R uses electronic sensors and hydraulically actuated clutches. It also has a yaw-rate feedback control system, effectively managing slip angle. Front-to-rear torque split can go from 2:98 during a standing start to a maximum of 50:50.2008 Nissan GT-R - Engine and AWD System - First Look - Motor Trend
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Models and types

ATTESA E-TS system is used in the following models: * R32 and R33 (1989–1997) GT-R, GTS-4 Skyline * Y32 and Y33 1992-2001 Nissan Cima Type II Limited S-Four * 1990–1994 Nissan Cefiro SE4, LNA31 *

Nissan Skyline GT-R The is a Japanese sports car based on the Nissan Skyline range. The first cars named "Skyline GT-R" were produced between 1969 and 1972 under the model code KPGC10, and were successful in Japanese touring car racing events. This model was fol ...

- 1989–2003 * Nissan Stagea * Nissan Laurel C34 (1994–1997) and C35 (1997–2002) * 1997–2003 Infiniti QX4 * Infiniti G35x/G25x/G37x/ Nissan Skyline (V35 & V36) * Infiniti M35x/45x/37x/56x/ Nissan Fuga *

Infiniti QX70 The Infiniti QX70, formerly called the Infiniti FX until 2013, was an Executive car and Crossover SUV produced between 2002 and 2017. The FX replaced the Infiniti QX4 as Infiniti's mid-size SUV. It shares the same Nissan FM platform as the rear-w ...

Infiniti EX The Infiniti QX50, marketed also until 2013 as the Infiniti EX (North America) and Nissan Skyline Crossover Japanese domestic market, is a rear- or all-wheel drive, five passenger, five-door Compact executive car and Crossover SUV, manufactured a ...

/ Nissan Skyline Crossover (with Active Brake Limited Split for side-to-side torque split, as needed) *

Nissan Cedric The is a large automobile produced by Nissan Motors, Nissan from 1960 to 2015. It was developed to provide upscale transportation, competing with the Prince Skyline and Prince Gloria, Gloria which were later merged into the Nissan family. In late ...

(Gloria/Cedric with RB25DET engine) * Nissan Skyline Sedan 350GT FOUR Hybrid/ Infiniti Q50 ATTESA E-TS Pro system is used in the following models: * R33 (1995–1997)

(offered as a factory option) * R33

V-spec * R34 (1998–2002)

V-spec, V-spec II and M-spec * 2008+

(different implementation)

References

External links