Gtr Skyline Differential Types ? Helical / Mechanical / Viscous Etc ?

[Butters]

Ok Can people fill in the blanks please ?

R32 gts-t = Viscous Clutch type LSD

R32 GTR = ??

R33 GTR = ??

R33 GTR V-Spec = ?? + some active lsd stuff

R34 GTR = Helical + ???

Now rumor mill tells me R33 / R32 GTR has mechanical One way Clutch type LSD. Does anyone know this for sure ???

[Butters]

soooo gtr owners don't know what diff they have in there car then ???

BTW yes I did seach already !!

[djr81]

Front diff:

Model number: F160

Ratio 4.111:1

No pinions: 2

Teeth pinion & spool: 9 & 37

It has no LSD capacity.

Rear

Model F200

Ratio 4.111:1

No pinions: 4

Teeth pinion & spool: 9 & 37

It is a mechanical LSD. If anyone tells you it is a one way or a two way just slap them & walk away.

Front & rear diff oils are different - the rear needing LSD fluid, again obviously.

Here is a drawing of the LSD internals.

[Beer Baron]

but the rear diff is a 2 way mech LSD?

[djr81]

The problem is that all the hektic & indeed fully sik dorifto heroes only understand diffs in the one way/two way description. This has become all pervasive & clouded peoples understandings. The mechanical LSD's typically used in road cars share the same style of friction plates as BOTH the 1 & 2 way diffs. So you can't say they are either.

The difference between the one & two way diffs is simply the angles of activation in the guts of the diff. It is these cone plates that impose load on the friction plates & make the diff lock up. A one way doesn't have the ramp angle (or atleast has a much larger angle) on the "over run" side of operation and therefore wont impose any load on the friction plates. It would be much easier if people used the ramp angles as descriptors as they actually mean something.

See here for the Cusco descriptor which is better than my cack handed effort.

http://www.cusco.co.jp/english/e_lsd.html

Edited May 30, 2007 by djr81

[Cubes]

I had my diff tightened up recently (gtr/gts4 center).

The bloke said... "its not a 2 way its just a standard factory center"

Unless I misunderstood.

Compression locks (in the wet) it locks both rear wheels?!? :S

It definitely doesn't appear to lock anywhere near as hard on decel as it does on accel. Give it light throttle it doesn't lock on sharp corners, give it just a little bit more than normal acceleration and it chirps the inside wheel and shudders the car. On decel sharp corners (i've tried first gear etc) it doesn't appear to lock chirp the inside wheel etc??

I can't remember how my buddy's 2way felt so not sure. lol

[djr81]

The point is that a proper 1 way, 1.5 way or 2 way has different components inside it which actively increase the clamping load on the friction plates when you get a differential wheel speed. The standard mechanical LSD in a Skyline does not have these components. The pre set clamp load on the plates is the only way of changing the limited slip qualities.

Edited May 30, 2007 by djr81

[Cubes]

Interesting...

So with enough power and the correct conditions the std mechanical will single leg it where as the aftermarket won't.

I wonder exactly what is contained within the nismo diff kit for the gtr/gts4's.

[djr81]

Well most standard LSD's (Maybe we will call them clutch type because that is the best description) will allow some wheelspin on the inside (unloaded) wheel. Mine does. You can increase the clamping force to prevent this but it becomes a pain in the arse when you just want to go down the shops.

A mechanical (as in Cusco, Nismo etc) LSD pllies clamping force to the friction plates of the diff when differential wheelspeed is experienced & torque is being applied - on both acceleration & decelleration in the case of a 2 way & on acceleration only in the case of a 1 way.

BUT is you have hiked the inside tyre the mechanical element of the LSD is good for SFA because the diff is then reliant only only the pre existing clamping force ie it acts like a normal clutch type LSD.

Here is a bit of thing on the ramp angles of the diffs ie the bits that define if it is a 2 way or a 1 way or whatever.

http://icpcitation.com/variloc_theory.htm

[Beer Baron]

for me it's as simple as this. in the centre there are the little legs (the spider?). force causes them to push on the ramps. with equal ramps on both side you have a 2 way. with a different ramp angle on one side you have a 1.5 way. with ramps on one side only you have a 1 way. It's been a while since I looked at the centre but from memory the ramps on both sides are equal. my memory is not the greatest so it's possible one ramps is softer than the other making it a 1.5 way but either way I'm positive being a 1/2/1.5 way has nothing to do with the cone washers or springs at the ends of the clutch packs putting pre-load against the clutches. They just make the diff operation more severe.

[djr81]

for me it's as simple as this. in the centre there are the little legs (the spider?). force causes them to push on the ramps. with equal ramps on both side you have a 2 way. with a different ramp angle on one side you have a 1.5 way. with ramps on one side only you have a 1 way. It's been a while since I looked at the centre but from memory the ramps on both sides are equal. my memory is not the greatest so it's possible one ramps is softer than the other making it a 1.5 way but either way I'm positive being a 1/2/1.5 way has nothing to do with the cone washers or springs at the ends of the clutch packs putting pre-load against the clutches. They just make the diff operation more severe.

You are entirely correct in your description of the 1/1.5/2 way. The pre-load is not related to the ramp angle. The ramp angles define the severity of the operation in both directions when torque is applied. A 30 degree ramp is harsh & a 90 degree ramp is completely ineffective (ie it is used on the over run side of the 1 way). But you can get different ramp angles & the diff is still a 2 way or a 1.5 way or a 1 way (except on the 90 degree side, obviously).

Maybe if someone had a photo of the pinion gear carrier & the pressure rings of an R200 it would help.

[Butters]

Awesome post djr81. Thank You !!

That diagram is tops, I can see clearly it is a mechanical clutch type LSD.

I get what you are saying about how it is different to a 1/1.5/2 way as well.

So my next question and its just outa curiousity is how does the Active Lsd work in a R33 gtr-vspec then ??

[Cubes]

Well most standard LSD's (Maybe we will call them clutch type because that is the best description) will allow some wheelspin on the inside (unloaded) wheel. Mine does. You can increase the clamping force to prevent this but it becomes a pain in the arse when you just want to go down the shops.

A mechanical (as in Cusco, Nismo etc) LSD pllies clamping force to the friction plates of the diff when differential wheelspeed is experienced & torque is being applied - on both acceleration & decelleration in the case of a 2 way & on acceleration only in the case of a 1 way.

BUT is you have hiked the inside tyre the mechanical element of the LSD is good for SFA because the diff is then reliant only only the pre existing clamping force ie it acts like a normal clutch type LSD.

djr81,

My std center has been tightened up and with moderate throttle is very tight.

As mentioned in earlier posts with moderate throttle it shudders, chirps and skips the inside wheel. The beauty of it is with light throttle limping around in car parks its 100% like a stock diff. No lock, no chirp nothing 100% streetable so to speak.

The aftermarket I have driven and been in are very harsh with their engagement, the slightest throttle and they are locking causing shudders, chirps and skips which is a masive pain in the arse when parking, when taking it easy and not to mention when police are close following or in the same car park.

What is the benefit of an aftermarket diff having such an aggressive ramp angle?

I can see its great for drift but for general street and track use? why?

[Cubes]

I've done a little digging and have some pics one of which is mine.

Apparently the R200 clutch diff from nissan is a torque sensing diff where the greater the load placed upon it via the tail shaft the harder it locks up. So makes for good street ability.

There are 2 types that are available from Nissan. One that is the std and the other that contains the nismo multi clutch pack.

Basically the std diff uses a spacer of sorts that takes the place of the nismo's multi clutch pack. There's a mob in the US that sell all the clutches required for next to nothing. ~18usd per clutch.

You can identify the two by its ramps.

Standard

Nismo

The nismo's pin is round with its ramps being flatter. Easy to tell the difference after looking at the pics for a little.

Apparently the stock clsd has issues with ripping the fingers off the clutch disk when running reasonable power with sticky tyres. The Nismo multiclutch pack sorts the issue as its considerbly tighter.

Correct me if I'm wrong as I've only repeated what I've read else where.

And the exploded view again.

Apparently the heavy duty R200 CLSD's part number is LOM59-XX 0YY. XX being the ring gear bolt and YY being the spline count.

The LOM59 (nismo) runs more friction plates and a shallower ramp angle.

[djr81]

djr81,

My std center has been tightened up and with moderate throttle is very tight.

As mentioned in earlier posts with moderate throttle it shudders, chirps and skips the inside wheel. The beauty of it is with light throttle limping around in car parks its 100% like a stock diff. No lock, no chirp nothing 100% streetable so to speak.

The aftermarket I have driven and been in are very harsh with their engagement, the slightest throttle and they are locking causing shudders, chirps and skips which is a masive pain in the arse when parking, when taking it easy and not to mention when police are close following or in the same car park.

What is the benefit of an aftermarket diff having such an aggressive ramp angle?

I can see its great for drift but for general street and track use? why?

I understand that tightening the clutch packs increases the LSD action with no torque input. So when you input some torque not so much is needed to get to the same mount of lock up as before when the thing wasn;t as tight.

From what I understand the reason you may want an aggressive ramp angle is basically to get the diff locked up as you feed throttle in on corner exit ie so it is ready & the car is settled before you get to 100% throttle. It is very much harder to stop a wheel spinning once it is started than to prevent it starting.

For general street use you probably don't want an aggressive diff - atleast I don't.

[djr81]

I've done a little digging and have some pics one of which is mine.

Apparently the R200 clutch diff from nissan is a torque sensing diff where the greater the load placed upon it via the tail shaft the harder it locks up. So makes for good street ability.

There are 2 types that are available from Nissan. One that is the std and the other that contains the nismo multi clutch pack.

Basically the std diff uses a spacer of sorts that takes the place of the nismo's multi clutch pack. There's a mob in the US that sell all the clutches required for next to nothing. ~18usd per clutch.

You can identify the two by its ramps.

Standard

Nismo

The nismo's pin is round with its ramps being flatter. Easy to tell the difference after looking at the pics for a little.

Apparently the stock clsd has issues with ripping the fingers off the clutch disk when running reasonable power with sticky tyres. The Nismo multiclutch pack sorts the issue as its considerbly tighter.

Correct me if I'm wrong as I've only repeated what I've read else where.

And the exploded view again.

Apparently the heavy duty R200 CLSD's part number is LOM59-XX 0YY. XX being the ring gear bolt and YY being the spline count.

The LOM59 (nismo) runs more friction plates and a shallower ramp angle.

Great post Cubes. Looks like I was getting my LSD types atleast part way confused. Dho.

The first photo is very definately a more gentle ramp angle than the Nismo (looks like 45 degrees & about 30 degrees with both sides being the same angle on the diffs, ie 45 & 45 and 30 & 30.) Remember drive is going vertically as the photos are shown. Can you change the ramp angles on the Nismo diff in the same manner as you can do it with the Cusco ones? Obviously the stocker is not changeable - you can only stuff around with the tightness of the plates.

You would expect the Nismo diff to run a more aggressive clutch pack.

Edited May 31, 2007 by djr81

[Abo Bob]

While I'm generally confused by this thread here is a pic of my Nismo 1 way. It locks up very easily and strongly.

[MotoMan]

Awesome post djr81. Thank You !!

That diagram is tops, I can see clearly it is a mechanical clutch type LSD.

I get what you are saying about how it is different to a 1/1.5/2 way as well.

So my next question and its just outa curiousity is how does the Active Lsd work in a R33 gtr-vspec then ??

The active LSD uses a computer and hydraulic pressure to lock the diff i believe... there isnt much info on the ALSD... which sucks as i have one in my gtst

Edited June 2, 2007 by MotoMan