Lsd Differential.. From What Cars Can We S12's Use?

Started by Aceprowler · May 8, 2008 · 22postsSMF 2010–26

AceprowlerMay 8, 2008, 3:10 am · #1

The one thing I would really like to do and do it soon is to get the back end sturdy before putting a bunch of power going to the wheels.

How do us 1985 Silvia S12 turbo guys get a LSD rear or Posi (in GM terms)

I see the R200 is a LSD rear but what can fit or work with. Any and all help welcome!

I think 1 wheel spin is the gayest thing!! lol

Plus I like to go out to the track and you can not get traction with just one wheel pushing!

lvDaveMay 8, 2008, 3:19 am · #2

Best to get an aftermarket one meant for a 240sx. One from a late 87-89 z31 will fit but they aren't that nice, especially for the price. I just sold one for $500. Do a search and you'll find everything you need to know.

AceprowlerMay 8, 2008, 3:40 am · #3

$500 isn't bad. But those models I can use on my 1985 200sx turbo then?

Thanks man!

lvDaveMay 8, 2008, 5:11 am · #4

Aceprowler$500 isn't bad. But those models I can use on my 1985 200sx turbo then?

Thanks man!

That's $500 used though. Which is almost as much as a new aftermarket one. The z31 ones aren't that nice either they only have 2 clutch packs on each side.

You should buy an lsd meant for a 240sx that did not come with the factory vlsd. Just keep an eye on the 240sx forums for a group buy. You missed out on the one at z31performance.com but another one might pop up sometime.

RedneckMay 8, 2008, 5:27 am · #5

I think the 240sx has different half shafts than the s12. Sure they will fit inside our differential case (r200 anyway) but then you have the half shaft problem. Why is it everyone is under the impression they are a more or less a bolt in item? From what I have seen the half shaft conversion to make the aftermarket s13 lsd's work is somewhat of a pain in the ass.

lvDaveMay 8, 2008, 5:32 am · #6

What's wierd is on this forum people find that they don't fit, but on the z31 forum quite a few people fit them no problem.

RedneckMay 8, 2008, 6:20 am · #7

lvDaveWhat's wierd is on this forum people find that they don't fit, but on the z31 forum quite a few people fit them no problem.

It has been documented in a few different threads that the spline counts between s13 lsd and s12 open diff are different. They also apparently have different shaft output bolt patterns. And considering no one has done any full writeup's on the s12 to s13 lsd install it is hard to get concrete information on the subject.

AceprowlerMay 8, 2008, 6:35 am · #8

So does this mean I'm stuck with my open rear then?

There is not a LSD rear that will work ?

gerrybgMay 8, 2008, 8:18 am · #9

You get an aftermarket diff centre for an original OPEN diffed S13 R200 and swap that into an s12 long nose R200 case, then the s12 R200 type CV splines fit fine.

The problem is only with diffs that had VLSD centre as the right hand side shaft had an extra smaller spline to operate the Viscous coupling.

Also its got to be for an s13 or early s14 which had 29 spline CV shafts, s12 R200 also have 29 spline CV shafts.
Everything after that, (including second series of s14) had 30 spline shafts.

AceprowlerMay 8, 2008, 8:43 am · #10

gerrybgYou get an aftermarket diff centre for an original OPEN diffed S13 R200 and swap that into an s12 long nose R200 case, then the s12 R200 type CV splines fit fine.

The problem is only with diffs that had VLSD centre as the right hand side shaft had an extra smaller spline to operate the Viscous coupling.

Also its got to be for an s13 or early s14 which had 29 spline CV shafts, s12 R200 also have 29 spline CV shafts.
Everything after that, (including second series of s14) had 30 spline shafts.

From your info I found this :

"The S12 uses a 'long' (same as S30/S130/Z31) R200 in the IRS models & an H190 in the live-axle version (which we got here in Aus).

The S13 onwards use the short R200 diffs which are not compatible with the S30. But you may be able to transfer the LSD assembly onto the earlier crownwheel/pinion. BUT you will still need to address the 1/2 shaft spline issue...

The best bet is get an R200 LSD from a US Z31 Turbo. Or if you can find one, an LSD from an R30 or R31 Skyline. Or buy a Nismo or a Quaife LSD.

My DR30 has a 3.90:1 R200 LSD & I've got hold of a 4.375:1 R200 LSD for my 240Z. Both of which have been rebuilt with new clutches (which aren't cheap). Breakaway on the 3.90:1 is 90 ft/lbs & the 4.375:1 is a little more civil @ 65 ft/lbs."

Is this correct what this guy says?

brewster240May 8, 2008, 8:52 am · #11

kinda.

z31 turbo diffs are rare, and expensive. rebuild parts are no longer available.

heres the bottom line.

your car has an open r200 long nose diff?

order an after market diff for a 1990 nissan 240sx. its that easy.

the rest of the info is just confusing filler.

gerrybgMay 8, 2008, 10:57 am · #12

Yep what he said. Key words in my info are "Replacement Aftermarket LSD Centre Only" , to suit "Short Nose Open R200 Diff s13 " will fit/swap into a "Long Nose" s12, Z31 etc etc type R200 diff.

(You unbolt your crown wheel off your long nose open diff centre and bolt it to the aftermarket LSD centre and swap it straight in and set up the backlash)

That's it.

AceprowlerMay 11, 2008, 4:10 am · #13

gerrybgYep what he said. Key words in my info are "Replacement Aftermarket LSD Centre Only" , to suit "Short Nose Open R200 Diff s13 " will fit/swap into a "Long Nose" s12, Z31 etc etc type R200 diff.

(You unbolt your crown wheel off your long nose open diff centre and bolt it to the aftermarket LSD centre and swap it straight in and set up the backlash)

That's it.

Thanks very much. I'm looking up the info now.

How then too can I get higher gears for highway driving?

I took it on the highway and I was like at 3,000rpm or higher just at 65mph.

I think I read these 1985 200sx 1.8 CA18ET HB Turbo have 4.11 gears. I have 3.73's in my Monte. I would like something in the low to mid 3's if possible. That is something with the rear differential. Has someone done this mod?

AceprowlerMay 12, 2008, 4:46 am · #14

AceprowlerThanks very much. I'm looking up the info now.

How then too can I get higher gears for highway driving?

I took it on the highway and I was like at 3,000rpm or higher just at 65mph.

I think I read these 1985 200sx 1.8 CA18ET HB Turbo have 4.11 gears. I have 3.73's in my Monte. I would like something in the low to mid 3's if possible. That is something with the rear differential. Has someone done this mod?

So does anyone know where to get an ring and pinion set to go from our gear ratio of 4.11 to 3.42? Or even 3.73's?

I'm going to be doing some high way driving with this car as my Daily Driver and would like some highway gears.

Thanks very much!

brewster240May 12, 2008, 5:11 am · #15

keep the gears.

its a 4 cyl, dont think in the terms you would with your monte, which has torque to keep the car moving at lower rpm's.

AceprowlerMay 12, 2008, 6:36 am · #16

brewster240keep the gears.

its a 4 cyl, dont think in the terms you would with your monte, which has torque to keep the car moving at lower rpm's.

Thank you but I don't like my low gears.

lvDaveMay 12, 2008, 6:56 am · #17

The SE came with taller gearing. Z31's also had a couple different gearings.

AceprowlerMay 12, 2008, 7:15 am · #18

lvDaveThe SE came with taller gearing. Z31's also had a couple different gearings.

The SE had 3.90 right?

The Z31's I'm looking up right now!

Thanks for your info man!

Those 4.11's are too high for me.

My turbo can't even catch up with the rpms with this high of gearing, lol.

lvDaveMay 12, 2008, 7:20 am · #19

I'm pretty sure SE's are 3.90

Here's the Z31 specs
http://www.az-zbum.com/information.differential.shtml

84-87 NA's are the most plentiful in junkyards. So you'll have no problem finding 3.70 gears.

brewster240May 12, 2008, 8:34 am · #20

AceprowlerThe SE had 3.90 right?

The Z31's I'm looking up right now!

Thanks for your info man!

Those 4.11's are too high for me.

My turbo can't even catch up with the rpms with this high of gearing, lol.

lol, what does that even mean?

the 4.11's make up for the engines lack of torque.

you put in 3.90's the car is gonna be slower in everyway. the turbo will take even longer to spool.

you may get lower rpms on the highway, but your gas mileage could be worse, due to the fact that you engine wont be in its powerband anymore.

like i said, dont think of this thing like you would with you monte, which has torque.

rageMay 14, 2008, 3:54 am · #21

im almost positive SE's are 3.7, ive got a pumpkin laying around i just want to put some fun gears like 4.3 or 4.6 in. i saw a 4.3 long nose r/p set on hybridz awhile ago, so i guess they exist?

but yeah the 3.7 r/p i have laying around is up for grabs

AceprowlerMay 14, 2008, 4:02 am · #22

rageim almost positive SE's are 3.7, ive got a pumpkin laying around i just want to put some fun gears like 4.3 or 4.6 in. i saw a 4.3 long nose r/p set on hybridz awhile ago, so i guess they exist?

but yeah the 3.7 r/p i have laying around is up for grabs

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