GTR V-Spec Active LSD & A-LSD - Where to begin Part III

------- V-Spec Manual -------
Various confusing quotes i have gathered:

#Nissan Manual that comes with the car, it recommends at the back that the oils for both Vspec and Mspec cars, and stock gtr34s all use api GL5 oil 80w90 nothing special

#A GL5 75w-90 or 80w-90 is ideal for most of the diffs, we sometimes recommend certain LS oils as they are very good in any diff.

#The V-Spec diff needs a SAE90 LS oil according to my data.

#You don't need a 75w-140 in any of the standard diffs, only in certain aftermarket ones.

#LSD oil e.g Castrol LSX90

#Fill on the diff itself like the gearbox - LSD diff oil
#Fill through reservoir - ATF for the active LSD

------- Active LSD ------- Source - Skyline Australia - by user PM-R33
Why this sticky about the A-LSD?

The problem with this has been that there is little technical information on the Active-Limited Slip Differential (A-LSD) even though it is now over a decade later since they were made. There is information about however the information is scattered all over SAU over a dozen threads. The purpose of this sticky is to have all the information in one place to save people time searching all over the place for hours on end.

What is an A-LSD?
For people's information reading this that aren't aware of what an A-LSD is, it's a rare factory option on certain model R33 GTSTs of having a R33 GTR V-Spec diff. The diff is controlled via an ECU in the boot next to the HICAS ECU. The ECU triggers a hydraulic pump that pumps a hydraulic fluid into the diff to lock it up when required. It does this by observing the behaviour of the wheels and when it detects that one wheel has broken traction it will send power to the other wheel to compensate and keep maximum traction. So in theory it is ment to behave like an open wheeled diff all the time and behave like a locked diff when needed. In theory this is great however it doesn't always go according to plan.

The problem is the response time. When a wheel starts losing traction the diff should instantly recognise it and go into action instantly without you even noticing. This would give perfect traction. The thing is this doesn't happen. The single wheel will break loose and in certain situations the diff will take ages to send power to the other wheel - sometimes not at all. This causes very unpredictable "tank slaps" when trying to go straight or when trying to slide.

How do I know if I have an A-LSD?
The way to spot whether a vehicle has an A-LSD is as follows:
#Cooling fins on the diff itself (and a large hydraulic line going to it)
#Hydraulic pumps and wiring underneath back rear of vehicle
#Hydraluic fluid resevoir in boot on right hand side
#Two ECU's next to battery in the boot (one is HICAS, the other ALSD)
#A-LSD and SLIP wording inside tacho on dash
#Resevoir in Boot
The resevoir in the boot holds the hydraulic fluid required by the A-LSD. The original Nissan fluid is called Matic D however it is expensive and hard to get. Instead Castrol Transmax Z can be used due to it being an equivalent fluid.

#A-LSD Fluid
The diff itself has "USE LSD OIL ONLY" stamped onto it so something like Castrol LSX90, Motul LSD oil or similar shall be fine. Some people have used non LSD oil it the diffs however I would do what Nissan says.

The following thread showed the main discussions about what fluid to use.
http://www.skylinesaustralia.com/forums/Re...=active+lsd+oil

Next we shall go into the problems that arrise with the tricky A-LSD.
Aftermarket ECU Problems
The first problem that arrises with the A-LSD is aftermarket ECU’s are not made with it in mind. This causes the A-LSD to go into instant failure mode as soon as the factory ECU is removed and something aftermarket is put into its place. The A-LSD light on the dash will illuminate to indicate a failure. Luckily this is a fairly simple fix but took a long time to find by some of the people here on SAU.

The following thread shows how to overcome this problem. Basically a TPS signal needs to be rewired to go the the A-LSD ECU in the boot.

http://www.skylinesaustralia.com/forums/Ec...Ls-t107656.html
Thanks go out to T04GTR, Moanie and PaulR33 for this.

Diff Lock Problems - Bleeding
So now going onto the main problems with the diff, the delay. One main reason that adds to the delay is air being trapped in the lines that the hydraulic fluid flows through. This air needs to be bled - just like in brake lines.

On page 3, PaulR33 wrote a bleeding method for the diff.

http://www.skylinesaustralia.com/forums/Re...d+oil&st=40

The main thing is to use the bleed nipple on the top of the diff, which most people never knew about and the bleed nipple near the pumps.

Diff Lock Problems - Full Control with Aftermarket ECU
Here is my DIY write up on how to get full control of the A-LSD with an aftermarket ECU. This means that you can setup the diff to function the way you want and have it locking up when you choose.

http://www.skylinesa...ftermarket-ecu/

Once again, great thanks to everyone involved in those threads, especially PaulR33 for all his hard work and posts regarding the A-LSD. Hopefully this sticky can continue to be a good information source regarding the A-LSD.

Cheers

Phil

-------  Attessa Bleeding How To Example #1 -------
NOTE: You need Nissan ATF fluid for this application. Check step "4" first so you can have everything ready to go.

Step 1: Fill tank 30mm above MAX line. "tank is located in right rear of your trunk"

Step 2: Open air bleeder on oil pump. Crack open till there is no more air coming out and you get fluid dripping. "This air bleeder is located on the pump on top of the rear diff. Bleeder is on right side. Can’t miss it"

Step 3: After you tighten up that bleeder you go and turn the ign on. Don’t start the car just turn the key to ign.

Step 4: You need to unclip the air bleeder connector. " This is a white clip located under the dash on the right side behind your kick panel" Opposite side of your ECU" Might be a good idea to un screw your kick panel before you do any of these steps. When this connector is unplugged it puts the pump in (air bleeder mode) and the pump operates at a fixed hydro pressure to the transfer actuator"

Step 5: You now need to bleed the nipple on the rear of the trans just below the tail shaft and above the hydro line attached to the rear of the trans. You want to give it 1-second blerps. You can hear the pump actuate while doing this. Do this step until there is no more air coming out the nipple.

Step 6: Go back to the tank in the trunk to check the level of fluid. Fill to MAX is necessary or just above. Now to finish the bleeding process you need to go back into the car to the air bleeder connector. You want to plug it back in and then UN plug it and plug it back in. You want to repeat this process until the lower level fluid in the tank in your trunk has a 5mm max air gap between the lower and higher level fluid. I had to plug in and unplug my bleeder sensor about 20 times at least. If you want get a friend to check the rear level while you sit in the car unplugging the bleeder sensor that might be easier. I had to do this on my own

If this doesn’t make any sense let me know and I can retype it for you guys  I’ve done a search on this info this week and also about a year ago on this forum and never came up with anything conclusive so now we got it.

This is the tank in your trunk. I didnt get any before pictures but this gives you an idea of the high and low level's of fluid and how it should look when your finished.

This is the bleeder on the pump above the diff. Its on the right side of the diff. Very easy to spot:

This is the bleeder on the trans. I used a clear hose so I could watch the air shoot out.

This is the air bleeder connector. The fsm tells you to make a switch but it is easy to plug in and un plug many times.

-------  Attessa Bleeding How To  Example #2 -------

WHAT YOU'LL NEED:
10mm Ring Spanner
A Piece of clear hose measuring about a foot long and an internal diameter of about 6mm.
About 3-4 litres of Automatic Transmission Fluid/Dexron III (You can use the original Nissan Fluid, but it's damn expensive)
A Funnel.
Bucket or drip tray.

How to:
If your talented enough you can probably do it on your own but i would reccomend having two people. One to open the bleed valve under the car and one to keep refilling to bottle in the boot.

Now onto the process
1. Drive the car up on ramps. Or jack it up and put it up on jack stands.

2. Lay down some card board if you dont have a creeper.

3. Inside the boot on the drivers side is a removable panel. Behind this panel is the bottle of fluid. This is where you will refill it from.

4. In the drivers side foot well. On the right hand side, there is a kick panel. After removing this you will find a lot of wires and only one plug. A white plug with a Yellow Wire with Green Stripes coming in and out of it. This is the "Air bleed connector". You must unplug this.

5. Going under the car from the front, slide towards the back of the car till you come to the back of the gearbox. At the back of the gearbox and the transfer case, just where the tailshaft begins, you will see a hose coming from the back of the car. This pipe runs to the ATTESSA Pump. Just above this hose is the Bleed nipple. This should have a little black cap on it.

6. Turn the ignition on. Don't start the car just turn the ignition on.

7. Now you need one person at the back of the car with the funnel in the top of the bottle. And one person under the car. The person under the car must put the ring spanner on the bleed nipple, then place the piece of clear tubing over the nipple. Now with the other end of the tubing, put it in the bucket.
Crack (Undo a little) the bleed nipple. Now the pump recognises a pressure drop and starts the pump intermittently. Only run the pump for around a 30 seconds to minute at a time. Tighten up the bleed nipple and the pump will stop.
Keep doing this procedure till the fluid coming out of the clear tubing turns pink. (Or what ever color fluid you are pouring in.)

8. After all this, tighten up the bleed valve, put the cap back on the bottle, plug the wire back in, put all the trim back and away you go.

** bleed nipple on the ATESSA pump itself, which should be used to bleed the pump first. It's a bit hard to see, but it's on the bottom of the pump and can be accessed from the drivers side of the diff just above the RH drive shaft.

Finish
ENJOY
If anyone should find fault in this write up, please notify me and i shall make the adjustments. As i had no manual or anything to go by this is just my way of doing it. And all from just interpreting a mixture of other peoples ideas and explanations

-------  GTR V-Spec Short Description -------

The GT/GF-BNR34 (R34) Skyline GT-R and GT-R V-spec models were released in January 1999. The R34 GT-R was also made to be shorter (from front to rear), and the front overhang was reduced. The valve covers were also painted glossy red, rather than dull black.

A new feature on the R34 GT-R is a 5.8" LCD multifunction display on the center of the dashboard, which shows seven different live readings of engine and vehicle statistics such as turbocharger pressure (1.2 bar max), oil and water temperature, among others. The GT-R V-spec model added two extra features to the display: intake and exhaust gas temperatures. Nismo Multi-function Displays (MFD) can be bought at an extra cost, they include a lap timer, G-Force meter and an increase in boost pressure measurement to 2 bar. The R34 GT-R was made shorter in response to customer concerns who thought the R33 was too bulky.

Like the R33, the new R34 GT-R V-Spec (Victory Specification) models come equipped with the ATTESA E-TS Pro system and an Active LSD at the rear, while standard GT-R models come with the non-Pro system and a conventional mechanical differential. The V-spec model also had firmer suspension and lower ground clearance, thanks to front and side splitters, as well as a rear carbon fiber air diffuser, designed to keep air flowing smoothly under the car.

Another special model of the R34 GT-R is the M-spec. It was similar to the V-spec, but had special "Ripple control" dampers, revised suspension set up, stiffer rear sway bar and a leather interior with heated front seats. The 'M' on the M-Spec stood for Mizuno who is the chief engineer of Nissan.
At the time of the R34's release, like the R32 and R33, Nissan released an R34 N1 model. The R34 GT-R N1 was equipped similar to the R32 and R33 N1 models -- a homologation special. It was sold without air conditioning, audio equipment, rear wiper, or trunk lining, but ABS remained. The new R34 N1 was also given the new R34 N1 engine. Only 45 R34 V-spec N1 models were produced from the factory, 12 of which were used by Nismo for Super Taikyu racing. The rest were sold to various customers, mostly racing teams and tuning garages.


-------  GTR V-Spec Series Breakdown------- http://sportscarforums.com/sitemap/t-3810.html

R32 V-Spec (Victory Spec)
* Four-pot Brembos with 324 mm discs front and two pot Brembos with 300mm discs rear.
* Retuned ATTESA E-TS 4 wheel drive system.
* Bigger 17" x 8" aluminium BBS alloy wheels with 225/50 ZR 17 tyres.
* Revised front suspension to accomodate the larger wheels/tyres.
* Curb weight increased by 20kg because of these modifications.

R32 V-Spec II
* Tyre size revised to 245/45 ZR17 due to N1 endurance (Gr.N) race regulations.

R33 V-Spec
* ATTESA E-TS PRO can redirect up to 50% of the torque to the front wheels within 1/1000th of a second.
* Active LSD system splits the torque between the rear wheels.
* Even harder, and 10mm lower, suspension.
* Expedia S-07 tyres. Bridgestone Potenza tyres are fitted to UK spec cars.

R34 V-Spec
* Underbody diffusers front and rear
* ATTESA E-TS PRO
* Active LSD

R34 V-Spec II
* updated ATTESA E-TS PRO and E-LSD
* carbon fiber hood

R34 V-Spec & V-Spec II N1
Special equipment

* Twin ball bearing metal turbo-chargers
* Extra large, air-cooled engine oil cooler

Equipment deleted from the GT-R V-Spec II

* Rear intermittent wiper
* Rear fog lamp
* Remote control entry system
* Passenger's seat vanity mirror
* Clean air filter
* AM/FM electronic radio and CD player (equipped with aerial and wiring loom.)
* Glove box damper & glove box lamp
* Super-fine hard coat paint.

Equipment changes to GT-R V-Spec II

* UV cutting insulation and front door green glass to just thin glass
* Side indicator lamp to a reflector
* Color coded electric folding door mirror is painted black
* Leather hand brake lever to lightweight resin
* Leather centre console lid to lightweight resin
* Full auto air conditioner to a heater with outside temperature display

R34 M-Spec (Mizuno Spec, for Kazutoshi Mizuno)
* Nissans new "Ripple Control" suspension
* Minor interior differences
* Special Gold and Green color options
* Basically a smoother riding V-Spec, nothing else changed

R34 Nur Versions
* Color options from M-Spec
* Some suspension and engine pieces from N1
* The last of the mass produced GT-Rs, the last ever being the Nismo Z-tune

Basically, it breaks down like this. You have the GT-R. The V-Spec models have a little harder suspensions, bigger breaks, and so forth. Just a slightly higher performing GT-R. The V-Spec II models were just slight updates to the standard V-Spec versions, nothing major. The N1 models are the track ready versions, with very stiff suspensions, quicker responding turbos, lighter materials, and so forth. The M-Spec just had a new Kazutoshi Mizuno designed suspension system. But, it was just a V-Spec II at heart, so its just a V-Spec II with a smoother suspension and some minor trim and color options. The Nur versions were a little mix of suspensions pieces from the N1 and some trim options from the M-Spec. A nice mix of track ready and good looking. They were the last GT-Rs built.
Skyline07