Above are pictures of the Nissan LSD. One of the first modifications I did to my car was installing the Nissan R200 limited slip differential. The 280zx, along with any car that wants to hook up and turn a good time, needs a posi-traction differential. My quest for the part led me to San Diego, Ca where I was very lucky to find the correct part. I called around and one junk yard said they had what I wanted. I took the trip out there and the differential they pulled was not a LSD. I decided to look around at some other yards and sure enough one yard had what I was looking for, needless to say I snatched it up quickly. The install went well. You will have to get a 79-83zx differential mount and remove the 300zx mount. The flange will have to be removed from your differential and installed on the LSD. I recommend using the CV type half shafts when you install the unit. I am not sure if the universal type half shaft will work, also the universal type half shaft is prone to breaking under race load conditions. Nissan made two types of differentials, the Clutch type (that came on the 87-89 300zx turbo car) and the vicious type( that came on the (white) 88zx turbo SE model). I have pictures of the clutch type, courtesy of Greg Kring on the zcar forum. The vicious type requires a change of the half shafts as they utilize a different type spline shaft that goes into the differential, so get the clutch type if possible and save yourself allot of time and money having half shafts made to work for your application.
NOTE: I have spoken to Nismo (Nissan motorsports) and was informed that Nissan rated this unit to only 280 foot pounds of torque and that really surprised me. I am putting almost twice that much power to the unit and it has not missed a beat, so go figure.
Here is a picture of the Torsen/Gleasen differential. This unit is an excellent addition to any zcar if you can find one. As I have learned, Torsen (was then bought out by Gleasen)made about 50 of these units for Nissan, and they were primarily used by the racing teams for Nissan. A few of them made it to the consumer market as well. These units are hard to find, but I do believe I have come across about three of them in the last few years. Note the barber pole type gears in the carrier. These are the gears that make the fully geared differential possible. I remember reading about the unit in the early 80's in some hot rod magazine that did a write up on the unit, and according to the article, the differential was capable of a 9:1 turns ratio and still maintain positive traction to both wheels. No wonder why all the racers wanted this unit.
I am in the process of upgrading my LSD unit with the Quaife posi traction unit. This is the very best differential you can get for any car. The Quaife differential is just like the older Torsen/Gleasen differential. The Quaife unit is the best solution to the upgrade. The Quaife is very similar to the Torsen unit, of course it cant be exactly the same because of patent reasons, but it is very close. I dont have a picture of the Quaife unit. I never took a picture of mine before install, but Quaife America is very close to me and I just may ask them if I can get a picture of the R200 unit. The Quaife unit is manufactured in UK, NOT in America, so if any shop trys to tell you different it is not the case. How do I know this? Well I called Quaife America, and the quys there did not know what the heck they were selling. All they knew is that it was for a 300ZX R200 diff. I ran into a problem regarding the snap rings with them as they told me that the stub axels were bolt in to the diff, which made no sense at all because as you know the 300zx had push in half shafts not bolt in. I ended up calling Quaife in UK, had the customer service guy pull the drawings and verify the snap ring configuration. What a pain in the butt, if you are going to sell a part, especially for that kind of money, then know what the heck you are selling.
I bought the unit at a cost of 1195.00 and they have a life time quarentee, with an unlimited horse power rating even under race conditions. That sounded good to me, I have some assurance with this unit I can have it replaced or serviced. The Torsen unit, if you can find one has no support, and if you call Gleasen they will inform you they never made a differential for the R200.
I was going to install the unit myself, but decided that it would be a better idea to have a company like Robello racing do the job. Not because I could not get the job done, but when I called Nissan for the various shims I would need they quoted me 10.00 each per shim. I looked at the Nissan manual and found they had this funky way of determining the shims required to set the preload on the side bearings and realized that was not a solution. I made some shims of two thickness and tried them but the unit was to tight in the bearings so I would have had to buy at least five shims to get the correct preload of the differential, and after that I would have to adjust the differential to get the correct backlash on the ring and pinion, so I could have easily spent 100.00 in shims to get this unit setup by myself, and that is if I lucked out and got the correct shims. I decided then, in stead of spending the money on parts I would never use again, I would let someone else that had the various parts to complete the work.
The Quaife differential unit utilizes the CV type half shafts for the R200 and that worked out very well for me.
Here are two excellent comparison's of the two different half shafts. The top shafts are utilized in the vicious LSD. You can see that doing an install of this differential will require custom half shafts. Note the longer shaft spline on the left side top. The two shafts below, are the more common type of half shafts. Note the two halvs are interchaingeable from side to side. I would highly recommend utilizing these half shafts if you plan on racing your car. I have not shown a picture of the universal type shaft as they do not apply to a serious horse power producing car.