What is ATTESA/ATTESA-ETS/ATTESA-ETS Pro and differences between v-spec & non-vspec ?
ATESSA E-TS PRO is Nissans 4WD system which transfers power and braking force where it is needed for best performance. Torque is split between front and rear wheels while braking force is split independently to all four wheels utilising ABS. In ordinary driving conditions torque is delivered purely to the rear wheels, however when the car is pushed the computer engages the front wheels and calculates the amount of power split between front and rear.
The Nissan Skyline GT-R is predominately a rear wheel drive (RWD) car. All power, be it a V-Spec model or not, is transferred to the rear wheels. The 4WD control system is called ATTESA. In true Japanese style, this acronym stands for "Advanced Total Traction Engineering System for All wheel drive". This system is used by Nissan on a majority of their 4WD cars and off roaders (Shogun, Pajero, etc.). There is a further refined variation of this system, known as ATTESA-ETS. Where ETS stands for "Electronic Torque Split". This is used in the GTR. Then, there is an updated version again, known as the ATTESA-ETS Pro. The Pro spec version is used on the V-Spec varient (it stands for Victory specification, in honour of the many Nissan motorsport victories, BTW). There are other versions (ATTESA-ETS Pro ELITE, used in motorsport and not commercially available, as there are undoubtably others).
The difference between the two GTR versions is that the Pro version has control over the torque split between the left/right rear wheels (via the A-LSD rear diff) - in addition to the standard versions front/rear lockup (which is performed via an electically pumped, fluid filled, transfer case arrangement). There are also other differences in how the torque transfer is performed front/rear. Namely to do with the ramp speed of the pump (which affects the progression of the lock up) as well the monitoring of various extra sensors.
The sensors used by ATTESA-ETS are a three dimensional G-sensor and the ABS wheel speed sensors. The V-Spec variant will take into account deceleration and vertical G's in it's torque split bias, whereas the standard non-vspec GTR will not. Both versions will take note of road speed differences (via the ABS sensors) and cross reference them with the G-sensor input. If ATTESA detects a loss of traction at the rear, it will proceed to gradually lock up the transfer case (by increasing the pressure of the fluid with the electric pump) until it achieves a full 50/50 lock. Depending upon the quality of the fluid, the state of the pump, the state of the clutch pack arrangements in the transfer case, you might not get a 100% lock (ergo a 50/50 split) and this is usually the case on older cars that have been thrashed. Basically, put the car onto some wet grass/dirt, Vspec or not, and dump the clutch at 8000 RPM in 1st gear. If you don't get 100% lockup within a second (a full 50/50 split) your ATTESA system might need some attention. As Vspec or not, your transfer case should be locked. More on the differences between Vspec and non-Vspec. The Vspec cars will take into account the vertical G's, so if the front of the car is dipping (due to a decline in the road) or under heavy braking, 10% is immediately transfered to the fronts (your torque transfer gauge should show this). Also on the Vspec, if you are in a hard turn, with the rears braking traction (drift) ATTESA should detect that you are in a moderate to high G sustained corner and not take action (the normal ATTESA-ETS will in this case). The Pro version will limit torque split to the fronts until such a time as your input from the steering wheel indicates that you wish to terminate the slide (by counter steering) at which point it will immediately transfer gradual lock (in correlation to the speed of your steering input, via the HICAS computer). The system is very complex, but there is more to it than the usual dealer story that 'there isn't much difference'. The truth of the matter is that most people will never push the car hard enough to find the differences, in conjunction with the fact that a lot of second hand GTR's have 'loose' transfer cases and the 4WD system has suffered. ATTESA requires that all the wheels and tyres are identical. The same grip level and rolling diameter. One of the common mistakes that people make is using different tyres (grip levels) and different sizes (your fronts and rears should be the same size, width and height) as any small changes will drastically affect how ATTESA interprets its input. Tyre choice is also crucially important. If you use crap tyres, don't be surprised to see the 4WD system doing strange things and the handling suffering as a consequence . (Quoted from Marios in Australia)
Hope this helps .
If you want more info just do a search .
Treg i thought that was a Hi5 post which was regularly reposted by Aitch
as 1 of his own. now your saying its yours wtf
i suppose you learn something new every day