# Serious diff question , professionals only



## Zen31ZR (Mar 24, 2004)

I have a chance to pick up an LSD diff from a 90 Infiniti M30 for quite cheap locally (as compared to the price of an 87 Turbo diff) And I have a couple questions.
#1: Is this the same R200 diff as the Z31? I have also heard of such things as a "long" nose R200 , and a "short" nose R200 , so I need to know for sure if this will fit.

#2: Even if maybe it's the incorrect size , can the internals be used in the R200 open diff case that I have on the car right now.


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## morepower2 (Apr 19, 2002)

[email protected] said:


> I have a chance to pick up an LSD diff from a 90 Infiniti M30 for quite cheap locally (as compared to the price of an 87 Turbo diff) And I have a couple questions.
> #1: Is this the same R200 diff as the Z31? I have also heard of such things as a "long" nose R200 , and a "short" nose R200 , so I need to know for sure if this will fit.
> 
> #2: Even if maybe it's the incorrect size , can the internals be used in the R200 open diff case that I have on the car right now.


Ok here is the skinny as I know it.

All R200 diffs before 88 including all Z31's are the old style long pinion type. The only excpetion is the M30, these were all long pinion as well, even into the 90's.

No M30's had LSD's, they all had open 3.90 ratio diffs.

Some long style diffs had 10mm ring gear bolts and some had 12mm bolts, usualy the turbos had the 12 mm bolts. Turbos have different axle spline counts as well.

87-88 turbos had limited slips. All except the limited edition model were clutch types and are rebuildable. The limited edition is a viscous LSD and it sucks.

Long pinion and short pinion differential units are interchangeable provided that the ring gear bolts are the same and axle spline counts are the same.

This is what I know.

Mike


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## Zen31ZR (Mar 24, 2004)

morepower2 said:


> No M30's had LSD's, they all had open 3.90 ratio diffs.



Well , I e-mailed the junkyard that has this diff and asked them specifically if it was a limited slip diff , and they said it was. So now I'm really confused. I guess the only way to find out is to go down and play around with it , see if it behaves as an LSD should behave (both axles turn the same direction , etc)


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## morepower2 (Apr 19, 2002)

[email protected] said:


> Well , I e-mailed the junkyard that has this diff and asked them specifically if it was a limited slip diff , and they said it was. So now I'm really confused. I guess the only way to find out is to go down and play around with it , see if it behaves as an LSD should behave (both axles turn the same direction , etc)


Or look at it. If you can see spider gears and not clutch packs, its not a LSD!

Mike


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## Zen31ZR (Mar 24, 2004)

morepower2 said:


> Or look at it. If you can see spider gears and not clutch packs, its not a LSD!
> 
> Mike



Thanks for the knowledgeable replys. :cheers: This is one of the reasons I came to this site.


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## KA24Tech (Feb 2, 2004)

Which junk yard was it? Most around here it seems barely know their head from a hole in the ground. I was out a Pull and Save in Aurora and they had an 86 Z31 which as I remember had an LSD. Then again after reading Mike's thorough description, why not just get a KAAZ or a Quaiffe or something like that so that you don't have question how long the used one will last if it is really one at all.

Troy


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## morepower2 (Apr 19, 2002)

KA24Tech said:


> Which junk yard was it? Most around here it seems barely know their head from a hole in the ground. I was out a Pull and Save in Aurora and they had an 86 Z31 which as I remember had an LSD. Then again after reading Mike's thorough description, why not just get a KAAZ or a Quaiffe or something like that so that you don't have question how long the used one will last if it is really one at all.
> 
> Troy


because Ball is the king of the no buck mods! He gets power from tweaks. 13's for less than 3 bucks!

The Z31 non viscous LSD is pretty damn good, espxialy if you shim the clutch packs up about 0.010 per side, it locks up like one of new camming diffs, well almost as good. Steve Mitchell runs a shimed stocker.

Mike


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## JAMESZ (Mar 12, 2004)

[email protected] It took me awhile to find an LSD also. It looks as if I will be dropping the subframe and putting in my new LSD. I'll tell you how it goes. Also my polyurethane bushings and my aluminum bushings are going in so we will see how long that takes  . I wouldn't trust the junkyard to much its probably just an open diff. 

Also morepower2 how hard is it to shim the shim the clutch packs 0.010 per side on the R200 LSD?


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## Zen31ZR (Mar 24, 2004)

KA24Tech said:


> Which junk yard was it?
> Troy


Eurasian. 

I wonder if that one at Pull and Save is still available and if it's a real LSD. A guy I know was telling me that one was a 2+2. Don't suppose you'd want to get it for me and I'd pay you for it , if it is the real thing? It'll be a few days before I can get down that way , especially since it's been snowing. You tell me what it's worth to you.


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## Zen31ZR (Mar 24, 2004)

morepower2 said:


> because Ball is the king of the no buck mods! He gets power from tweaks. 13's for less than 3 bucks!


It was more like $20 , and I don't mind spending some money for an LSD. Looks like that is about the only thing keeping me down from low 13s. That and a crappy clutch. :thumbup:


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## 0341TODD (Nov 15, 2003)

Hey- I thought I had posted a thread in here but I guess I didnt. WITH MY CAR WHICH IS AN 87 TURBO, my one wheel spins forward and the other spins backwards- so whats the deal with 86 and up having lsd from the factory? Why is mine an open diff? Can I keep my stock case and put an lsd in? I was coming back from subway for lunch and to catch a light I had to make a u-turn- DUDE, I SLID THE ASS END OF MY CAR AROUND AND TOOK OFF SIDEWAYS!!! IT IS SO GREAT FINALLY OWNING A CAR THAT IS REAR WHEEL DRIVE WITH POWER!!!!!


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## morepower2 (Apr 19, 2002)

JAMESZ said:


> [email protected] It took me awhile to find an LSD also. It looks as if I will be dropping the subframe and putting in my new LSD. I'll tell you how it goes. Also my polyurethane bushings and my aluminum bushings are going in so we will see how long that takes  . I wouldn't trust the junkyard to much its probably just an open diff.
> 
> Also morepower2 how hard is it to shim the shim the clutch packs 0.010 per side on the R200 LSD?


You got to go to an industrial supply store and get some stainless shim stock, cut it to size and stick it under the cone washer preloaidng the clutches.

Mike


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## Zen31ZR (Mar 24, 2004)

morepower2 said:


> You got to go to an industrial supply store and get some stainless shim stock, cut it to size and stick it under the cone washer preloaidng the clutches.
> 
> Mike


Isn't that a bit like welding an open diff? Doesn't it make it harder to turn corners and such?


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## JAMESZ (Mar 12, 2004)

0341TODD said:


> Hey- I thought I had posted a thread in here but I guess I didnt. WITH MY CAR WHICH IS AN 87 TURBO, my one wheel spins forward and the other spins backwards- so whats the deal with 86 and up having lsd from the factory? Why is mine an open diff? Can I keep my stock case and put an lsd in? I was coming back from subway for lunch and to catch a light I had to make a u-turn- DUDE, I SLID THE ASS END OF MY CAR AROUND AND TOOK OFF SIDEWAYS!!! IT IS SO GREAT FINALLY OWNING A CAR THAT IS REAR WHEEL DRIVE WITH POWER!!!!!



What month was your car produced in 87. The reason being that not until 4/87 did LSDs come in Turbos. You could have a early 87 so you might have just missed the cut off.


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## Zen31ZR (Mar 24, 2004)

JAMESZ said:


> What month was your car produced in 87. The reason being that not until 4/87 did LSDs come in Turbos. You could have a early 87 so you might have just missed the cut off.


So what about the LSDs in the 86's , then. When I was looking at diff parts online and asked about an 86 , the site asked if it was locking or nonlocking. Apparently must have been an option or at least available in 86.


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## 0341TODD (Nov 15, 2003)

my car was actually made 9/86


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## JAMESZ (Mar 12, 2004)

There were never any LSDs in the 86s. 4/87 was the first month the LSD was available in the Z31.

LOL Todd that would explain why you don't have an R200 LSD.


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## 0341TODD (Nov 15, 2003)

ha- aint that some shit? is there any way to retain my stock rearend and get an lsd----keep the case I mean? or should I just start looking for a used lsd.


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## JAMESZ (Mar 12, 2004)

Well see they are all R200s the reason it is called an R200 is because of the case so getting another R200 LSD would just be the easy thing.


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## morepower2 (Apr 19, 2002)

[email protected] said:


> Isn't that a bit like welding an open diff? Doesn't it make it harder to turn corners and such?


It increse your breakaway torque and makes it lock up harder like a more modern camming actiuon LSD. It will chirp more for sure.

Mike


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## Zen31ZR (Mar 24, 2004)

Another question for you , Morepower2. Would a welded diff be streetable? It's an option I'm considering if I can't find a LSD fairly soon. The car doesn't get driven a LOT , per se , so even sorta unstreetable I can live with. I know it wouldn't like turns much , but would it lock up the tranny or rip the diff apart if I turned a corner too sharp , or just make the inside tire spin and squeal.


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## morepower2 (Apr 19, 2002)

[email protected] said:


> Another question for you , Morepower2. Would a welded diff be streetable? It's an option I'm considering if I can't find a LSD fairly soon. The car doesn't get driven a LOT , per se , so even sorta unstreetable I can live with. I know it wouldn't like turns much , but would it lock up the tranny or rip the diff apart if I turned a corner too sharp , or just make the inside tire spin and squeal.


I don't consider it to be streetable, it will not want to turn well and chirp and squeal. You can drive it on the street but I definatly would not make it my everyday driver.

Mike


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## Zen31ZR (Mar 24, 2004)

morepower2 said:


> I don't consider it to be streetable, it will not want to turn well and chirp and squeal. You can drive it on the street but I definatly would not make it my everyday driver.
> 
> Mike


 Just an option I'm considering. I want to be in the 12s by the time IDRC comes to town , maybe I can run in one of the QUICK or STREET classes(I forget which is which) I prefer heads-up to bracket racing.


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