Replacement / Repair Of Vspec Diff

[paulr33]

got the car back. it feels the same. spins way too much for it to be locking. the light comes on so the puter i can only assume is doing what it is supposed to. i guess the next step is to work out the how pump gets power and try and hard lock it.

[MANWHORE]

paul, as I said before, watching with eager eyes.

Ps: 350 is a lot of money to just remove the diff.

It's actually easy to remove the diff yourself. The difficult thing is changing the centre - that needs alignment. My friend got his centre changed for 150$

That switch sounds like the goods.

[MANWHORE]

That's why I was asking you before about wwhat you thought of the performance of your diff.

If I do a burnout, it will spin both wheels. although, one won't be spinning much, but it does spin.

But just generally, like very quick twisty driving, the diff never locks. I doubt this is how it's meant to perform.

I have a friedn with an r32 gtst with a brand new stock diff - was replaced under warranty. I'm 100% sure it's stock, because i saw the workshop open the parts, all in the nissan boxes and all.

It actually feels quite tight. Obviously not clunk clunk chatter chatter as you go in a tight corner, but if you press the gas a bit more, you can feel it biting.

[paulr33]

yeah mine used to perform kick ass

we've seen it lock solid for 30 seconds odd

and leave a big darky on the street

so i did lock hard as previously

and it used to glide when going sideways as well

so it did have the capacity to as well

i think it could be a case of the pump is lacking oil pressure

or strong pressure so it doesnt lock strong enough

[paulr33]

a bit of wind but you can see it smoking from both sides

and it left double wheel'd darkies

that was feb 2006

when i had just completed the wiring look hack to make it work with the powerfc

it was the first time i actually had it not erorr (a-lsd come on normally) with the powerfc

so i had to test it and it locked awsome

[paulr33]

the guy at northern differentials who opened it up said that the diff is at the mercy of the pump. it needs good pressure to make it lock. if the pump or puter doesnt do whats its supposed to, then it wont lock very hard he said. he was very surpirsed when he opened it up. he said its a very strange diff

[paulr33]

actually i am confused. maybe just pulling it out, flushing and cleaning it and putting it back has fixed it? the car seems to be really nice gliding when i bag it up and it seems to really swifting sliding when its lost traction. i did a bit of a curry run today on the street out the front of work and walked past it just before and its left two perfect darkies on the road. so its locking it seems

ill need to do some more testing

[paulr33]

next step is to see what pressure is coming out of the pump when it locks

ive also noticed greenline list all their aftermarket lsd's as not suitable for active lsd models

NISMO GT LSD Pro 38420-RSS15-B5 / 38420-RSS20-B5

(Differentials) ¥101,640

Selective type. 1.5 or 2 way. Kit includes, LSD oil, side flange, oil seals, gasket ring gear bolts.

Not suitable for use with vehicles fitted with active LSD.

[paulr33]

this is the tech view from nissan fast

its listed as the torque split system

i was looking for lsd and a-lsd

[paulr33]

another view of the pump system

[paulr33]

did some more fiddling today. we found the pump gets 12v at startup and then 4v at idle. we only saw this once and was unable to replicate it. we tried to watch voltage when the system went into slip but couldnt pick up any signal (not sure why). we ran a 12v off the battery directly via a relay switched from in the car and u can hear the pump come on and lock. it seemed to be heaps better and actually spin both wheels. but now im not so sure. the pump is making a wierd noise. tomrrow we'll pull apart the oil lines and see how the pressure is flowing around. maybe its too low. but the override switch is cool

[paulr33]

i think the next step is to lock it via the switch

and then plonk it on a dyno to see what each wheel is doing

i suspect the pump is ceased or not strong enough (really tired)

[paulr33]

completed the override button today.

a proper button with led to indicate when on.

its protected by a 30amp fuse and relay system

so i can choose between computer controlled pump or manual run.

i think the pump is preload system and isnt used when the car is actaully spinning. cos if i run it normally when the car isnt moving u can hear it come under pressure and load by the tone of it. you can see the lsd fluid level drop when the pump runs (right hand side of the boot). so it appears the pump is ok. i might do some testing later tonight when its dark. im going to pressurize it and then turn the pump off (well back to normal puter mode) and do a burnout and see how it goes. i think having the pump hard locked on whilst doing burnouts or "slipping" makes it worse. i think a hard pressurize before a burnout and then drop it to normal mode may yeidl the best results. will also try and plonk it on a dyno in the next day or so to see whats going on in the rear end

[paulr33]

ok did some testing on some private roads.

1) sideways

come up to a corner in 2nd gear

leave puter in normal mode

turn the corner and boot it, lots of wheelspin and it carries on like usual

slip comes on and it operates normally.

2) takeoff

come up to a stand still. stop.

turn on diff lock. take off

lots of axle tramp and a bit of double wheelspin

a big improvement for traction

3) rolling clutch dmp

rolling. turn on diff lock.

boot it. a little bit of wheelspin

it feels to bring the car around a bit more and direct it properly

4) roundabout

come into the roundabout

turn on diff lock while rolling

boot it. a bit of a double wheel spin and glide out of the roundabout

so far a big improvement

just not sure how safe it is for the pump

or how long it will last like this (being hardset to 12v on demand)

[paulr33]

did another test today

come up to an intersection

turn on diff lock

turn the corner in 2nd

give it curry

nice double wheel spin

im going to look into getting the hydraulic fluid line for it braded so that it dosent rupture under pressure and also an oil pressure guage on it so it doesnt go bang from excess pressure

[paulr33]

ive noticed when the pump runs for more than 2 seconds and the computer doesnt expect it to run it failds. it must have a pressure sensor and its picking up pressure when it isnt expecting it and thus fails. hopefully i can work out an override relay switched for the pressure sensor

[paulr33]

have ordered a poor mans auto guage oil pressure guage

with elec sender so i can monitor pressure in the diff

im worried it might get mega high when its hard locked at 12v

[paulr33]

there is a pressure sensor switch attached to the side of the pump

if it detects pressure it turns on a relay to the puter.

the puter must check this in real time and fail if it see's pressure when its not in slip mode. so we'll be attached this pressure switch into a our relay loom so its ignored when i hard lock it, this will prevent the puter failing when driving normally. cos i have to reboot the car when a-lsd fails, just a bit annoying.

[MANWHORE]

Far out mate. top work.

Is that pic with the burnout your driveway?

Man I wish I had one of those.

[paulr33]

will get onto taking out the pressure signal sensor so a-lsd doesnt fail when i run the pump manually