'Scuse me while I kiss the sky

[oilleak]

Well I said I'd post some LSD info so here's what I've got so far. You'll quickly see how trying to figure out the H190 Limited slips can induce a serious purple haze.
There were three different Limited Slip units made - we'll call them early, middle, and late. Visually it's very difficult to tell them apart as they look the same and have no markings at all. Any of them will work in a roadster pumpkin (3rd member, case, aluminum chunk, whatever you want to call it). The internal parts of each may or may not be interchangable. Pressure rings and pinions probabley won't interchange - don't know for sure. Friction plates, disks, and spring plates/disks, will to some degree. For example the friction plates from a late diff may work in an early diff but those from the early diff may not fit into the late diff. Only a guru or someone with a whole lot of internal LSD parts can figure that out as it's not writen down anywhere - at least not publicly. What's more, there are different thicknesses of friction plates and disks and different internal set ups - some newer LSD's have been seen which only have 2 disks on either side. As far as i know, most units use 6 disks on each side.
Now we'll start to turn this into a rubic's cube. In addition to the three types of diffs, two different offsets exist within each type. The offset is the distance between the ring gear mounting flange face and the centerline of the diff's pinion (the part the carries the spider gears). This will be either 26 or 30mm. 26mm diffs can only run 8 tooth pinion gear sets (4.38, 4.63, 5.12). 30mm diffs can run 3.70, 3.90, and 4.11 gear sets. They can also run the above 8 tooth pinion gear sets if a 4mm spacer is installed on the diff which effectively reduces the offset back to 26mm. Still with me? Not for long! Turns out there are also two different roadster pumpkins (not to even start on all the other non-roadster varriation such as the H190ML from the later pickups). I think most pumpkins have a 22mm offset but there's also an 18mm offset pumpkin. This offset is the distance from the centerline on the carrier's pinion shaft (the pinion in Ring and Pinion) to the center of the diffs pinion shaft (the one that carries the spider gears). the result is that the overall offset (flange height) can be either 48 or 52mm's. This flange height affects which gear sets you can run and whether or not you need the spacer. Problem I've got now is that what i've got written down (I was careful when I was writing this stuff down) appears backwards from what I'm seeing on my diff. 48mm flange height is supposed to be for 3.70-4.11 gears but IF all the above is correct, That's backwards and 52mm is what you need for 3.70-4.11
My head is starting to spin again so I'll stop now. As I get this figured out, along with at least some info on friction plate/disc interchangability and set up issues, I'll post it.
Will - bottom line is that you shouldn't feel too bad about spending a grand on brand new one as you don't have to find parts and probably don't need to do any set up although it wouldn't be a bad idea to check the breakaway torque setting - too loose and it wont lock up much if at all, too tight and you have those funny locked diff handling problems. Once I've got a better handle on parts info, I'll start figuring out tuning these things for propper breakaway torque - which of course is different on every car do varriables like tires and driver prefferances. Hopefully this will wind up being useful info down the road as the LSD's need to be freshened periodically since the breakaway torque declines over time. I understand that if you're very compeititive in autocross, it's advisable to rebuild the unit once a season.

[SLOroadster]

Uh?! That was deep. Smoke is clearing....I can see clearly now. $1000 is what NISMO was just selling the LSD unit for. I actually think i got a good deal. I also think it was set up with a fairly high brakeaway setting as the previous owner bought it with the intent to either roadrace or drag race his roadster. The project was abandoned and I reaped the rewards. I might get around to installing it this weekend. I just finished repainting the axel assembly so everything looks good.

As far as figuring out how to set up an LSD, give Gordon Glasgow an email. I am told that he knows them very well.

Will

[oilleak]

When you get it in, let us know what you think. Out of curiosity, What tires are you running?

[SLOroadster]

Right now I just have a set of 185/60/14 Pirelli P4000 super sports. Unfortunetly I don't think I can run a larger size tire in the back with my current wheels. I'd like to put a set of Falken Azenis on because those things grip, and they are cheap. I am half-hartedly looking for a 2nd set of wheels that have a better backspacing. I might have a line on a set of Revolution 5 spoke wheels that appear to be pretty lightwight. My 280Z 6 spokes are about 13lbs each so they are hard to beat.

Will

[oilleak]

You'll love the Azenis. I have 195/60-14's on 6.5 inch Minilites with a +13mm offset and have no clearance issues. Loads of stick and let's you take advantage of all those other go fast goodies.

[SLOroadster]

My friend has a set of Falkens on a set of ARE Libras, I have been tempted to swap wheels with him but I think he would notice....