The Correct Behaviour Of An Active Lsd

[gts-4 dreamer]

What situations should an active lsd deliever drive to 1 wheel more than another if infact it is capable of this as I have read in some places?

what situations should it simply lock as I understand it certainly should do this?

what situations should it open wheel AND deliver power if infact it is supposed to?

Slip is an easy light to engage what about the alsd ?

Essentially I want to know how it, I understand its hydrolically engaged lock but it seems some believe it to work in a similar fashion to the rear diff in an EVO, has this any basis in reality ?

seriously confused eh cheers guyz

edit : some speeeling etc

Edited October 19, 2006 by gts-4 dreamer

[T04GTR]

it behaves like a lazy viscouse lsd and is crap

[T04GTR]

the slip light comes on when its "trying" to corect wheelspin

[gts-4 dreamer]

why would a viscouse lsd require a controller ?

lazy as in slow to engage ?

crap becuase you gave so many reasons why its crap or because its expensive to repair or becuase you have experience that is somehow useful that you didnt post?

Cant read your mind dude....l help a brother out an gimme something useful eh?

p.s. if slip light indicates its attempting to correct the stuation and not detecting slip? then what is the a-lsd light for ? what does it indicate ?

I just want to know how its supposed to react so I can tell if mine is working properly, if it is then I would change it, if its not i would like to know how it is supposed to react so i can be informed with either repair or replacement.

cheers fulas

Edited October 21, 2006 by gts-4 dreamer

[ookami]

When i was looking around buying a GTR I found a few good writeups about the effects of the A-LSD not always being good and sometimes being slow to respond and sometimes in uppredicatable fashions. For this reason I went for the non vpsec, not only did this save me 5 grand or there abouts on the purchase price but also gave me a mechanic LSD which is relatively cheap to repair/replace and upgrade when compared to an A-LSD setup. Also from what i have seen of the workshop demo cars in japan, the A-LSD are actually removed from quite a number of their A-LSD euiped cars. Try searching www.gtr.co.uk or this forum for more info. I found most of the information about it in those 2 places.

[ookami]

because I'm nice here's a few links from some quick searches

http://www.skylinesaustralia.com/forums/in...howtopic=128917

http://www.skylinesaustralia.com/forums/in...howtopic=128328

http://www.skylinesaustralia.com/forums/in...howtopic=107656

Edited October 21, 2006 by ookami

[gts-4 dreamer]

thankyou, i've read 2 of those 3 threads before, they werent as long then but they still dont answer my questions.

after re-reading them again I can see it seems to open wheel or lock but not distribute between either wheel as far as people can see, though is listed in nissan fast as a torque distribution system which could mean it either it decides to lock and distribute to both on slip detection or it may distrbiute independantly.... though thinking about the newer descriptions of the internals of the diff im thinking its more along the lines of open or lock and nothing but and will open wheel until warmed up which doesnt take long but if for instance you warm your car up like i do before taking off, cold tyres and cold diff = open wheel smoke, soooooo comp controlled locker......

mine hasnt ever been slow to react yet and i do get the pre-load few second buz on start up.

cheers i think i know what i need to now, I thnk i might keep it a while longer, think it might be interested in nissans use of this lsd, open wheel to save petrol and have the l;sd when you need it ?

p.s. thanks for hte links, i ignored the links i read before thinking nothing new would have come up but the user actually went through some testing with some interesting results.

Edited October 21, 2006 by gts-4 dreamer

[T04GTR]

why would a viscouse lsd require a controller ?

lazy as in slow to engage ?

crap becuase you gave so many reasons why its crap or because its expensive to repair or becuase you have experience that is somehow useful that you didnt post?

Cant read your mind dude....l help a brother out an gimme something useful eh?

p.s. if slip light indicates its attempting to correct the stuation and not detecting slip? then what is the a-lsd light for ? what does it indicate ?

I just want to know how its supposed to react so I can tell if mine is working properly, if it is then I would change it, if its not i would like to know how it is supposed to react so i can be informed with either repair or replacement.

cheers fulas

dont get all shirty lol.

it should be like a car with a loose diff. it should give a smoth progresion from inside wheel spin to no wheel spin. its not designed to hang thge ass out. its a "luxery" item thats not meant to be driven hard.

crap because.. for your aplication i think..theres many aftermarketr difs out there that perform better and are more predictable. most of the time they just dont quite do what you want. make any sence????

the a-lsd ligt is a warning light lol. just like the abs light. if its on it ailnt working. the slip light is a indicator that its operating. just like the traction light or esp light in a merc.

from my experiance they are rare as. and very doie. you cant do line lockers in them either coz with your foot obn the brake its logs a fault code for front wheel speed sensors.(basicly gets all confused.)

ps.. if your gopnna get a power fc get one for an auto not a manual as the manual pfc is missing a pin for the a-lsd ecu (tps output)

[paulr33]

hi

from my experience and fiddling with the active lsd system

it is the following

its not a mech lock lsd

its not a viscous lock lsd

its a hybrid of the two

internally it has a normal lsd centre that is "locked" by hyrdaulic fluid

the hydraulic fluid is the same attessa fluid in the gtr (castrol transmax Z)

when the system detects tractions loss via abs wheel speed sensor is turns the a-lsd pump on which applies fluid pressure to the housing. the pressure causes the internal cogs in the lsd housing to lock. thus you get a mech lock on demand based on wheel spin.

the system works really well when it works, mine is internmittent single spinner as i think there is an airlock in the system somewhere

ive got a manual override button for my vspec system so i can manually lock it on demand. that is mech lock whenever u want, asssuming the pump can provide the pressure to lock it. works pretty well

if A-LSD is ON then it means system failure and it will default to single spinner mode

if SLIP is ON then it means the system has decided you've lost wheelspin and its enabled the lock system, that is, its turned the vspec or a-lsd pump on

the best way to test it, is stop, turn steering wheel full lock, floor it, if it works SLIP will come on and it should glide sideways at least a 180deg spin almost

if its not working it will carry on, tramp and hardly move at all, that is, it will stay in single spinner. if A-LSD light is on, dont bother, it means the system has detected an error and has given up

[MerlinTheHapyPig]

hmm, interesting writeup paul,

so with your manual over-ride button, how good is the diff in always on mode?

i mean, is it fully like a locker at any speed? or does it crap out and start single spinning (like a worn viscous...)

[paulr33]

it has mixed results

i think i have an airlock in the system

so it doesnt completely lock properly

havent tried it recently

but with the pump on, the diff is forced to full pressure

[T04GTR]

hrmm. thats one way of doing it. nice work

[paulr33]

its dodgy but it works

basically we used a 4 pair wire relay and intercept the power for it

and just hard run the power when i turn the switch on.

when the switch is in the off mode the pump gets power from the a-lsd puter noramlly. when you run the pump manually after about 3 seconds and pressure has built up the a-lsd system fails and the computers shuts down. that is

A-LSD light comes on and it wont activate auto slip mode anymore until you reboot the car. this is because the pressure sensor on the mech lines sense's pressure and says to the puter hey turn the pump off, i can see pressure in the line, but the vspec puter goes "but i never turned the pump on in the first place", something must be wrong so it aborts and fails itself. pump still runs fine and locks, it just wont lock itself when the puter detects wheelspin

[T04GTR]

interesting