Dreaming LSDs

[ensys]

I couldn't agree more about Mr.7tooZ's offer, but sadly, without good timing, luck is sometimes wasted.

 

I was referring to the alloy rear cover (sorry, not "plate") and to the front mounting point of the "long nose" (and thanks for that heretofore unknown info about noses).

Also, thanks for confirming that the ZX LSD was the clutch type.

Now, all I need is opportunity coinciding with budget. But I'm now better prepared for the eventual occurrence.

 

Thanks.

 

 

[7tooZ]

Here are some notes I saved from HybridZ forum:

The LONGNOSE R200 is the diff that started to appear in the 260 2+2 and continued through the 280Z and 280ZX manual, and also came standard in all Z31 cars as well. Some 200SX’s also came with this diff, and probably others. This diff is strong enough for most Hybrid Z cars, and is by far the most popular swap. All of the 280Z and ZX’s and 200SX’s came with 2 pinion open diffs. These of course suffer the same weakness as the previous diffs. 87-89 300ZX Turbos came with clutch LSD’s (CLSD). The Nissan CLSDs are all 4 pinion, and the pinion gears are very strong in the LSD. There have been complaints that the CLSD would start to slip like an open diff with more than 300 lb/ft of torque. This seems to be a problem with the clutch pack design. In order to save money it appears that the clutch packs were skimped upon, using a thick solid washer to make up a large portion of the clutch pack thickness. The result is that the tabs on the few clutches that are actually in use will break under heavy drag racing use. Some (only some) Nissan Comp diffs have a better more complete clutch pack, but how exactly one determines which have more clutches and which have fewer has yet to be determined. There has been at least one case of a racer buying a LSD from Nissan Comp and getting the shoddy clutch pack setup. Some members here have gone to the trouble to make their own clutches to replace the spacer in the LSD, which should provide a lot more strength for high torque applications. There is also a viscous LSD (VLSD) which came in the 88 SS version of the 300ZXT. This is a rare diff indeed and the spline count of the LSD unit is different than the CLSD or open diffs, so if you buy one, best to be sure you get the original CV’s with the diff.

The R200 is wider than the stock R180 diff that comes in the 240Z, but most people use the stock halfshafts when they swap this diff in. This can lead to the halfshafts bottoming out which can cause handling issues. For more info read the R200 Handling Issues link here: http://www.betamotorsports.com/benchracing/index.html The solution here appears to be to use the CV joints from the 300ZX Turbo when installing into a 240Z.

The parts list needed to bolt in a longnose R200 into a 240Z is as follows:

1. mustache bar from 280Z with R200
2. yoke (companion flange) from 280Z  or 280ZX with R200
3. rear cover from 280Z or ZX with R200
4. side stub shafts from 280Z or ZX with R200 to bolt up to stock halfshafts
FOR EARLY 70-71 Z's only, you need 5 -7.
5. Longer 72-78 driveshaft
6. Curved transverse link that sits right behind the diff from 72-78 Z
7. Flip front diff mount around on crossmember

5-7 are necessary because the early Z's had the diff mounted forward, and swapping to the R200 moves the diff rearward. Obviously if you buy a diff from a 280Z with an R200, it has everything you need except the mustache bar. If you buy the 300ZX diff, then you need the above pieces.

Here are some more resources for the R200 swap: http://zhome.com/ZCMnL/tech/R200.htm. http://www.zbarn.com sells a kit containing all the parts necessary to do the swap. It's part number is DT1299.

Another option is to convert to CV shafts. If you do that, then you need the CVs from the Z31 300ZX Turbo along with an adapter, and you no longer need #4. Adapters are available from http://www.modern-motorsports.com.'>http://www.modern-motorsports.com. There is also a way to convert to 280ZX Turbo CV's as well. These aren't as strong as the later CV's. Modern Motorsports has those adapters as well.

It is also possible to modify the rear transverse link to clear the finned cover of the 300ZXT rear cover. This requires a bit of fabrication, but is pretty easy and has the advantage of a larger sump and cooling fins to allow the diff to run cooler. If you do this then you don't need #3.

The longnose R200 diff has been used for extremely powerful drag racing cars, all the way up to 9 second ¼ mile times, but it seems to be generally accepted that you can run 400 + lb/ft through them without any damage, except clutch damage in the case of the Z31T clutch LSD

[Zed Head]

Attribution... http://forums.hybridz.org/topic/49194-differential-cv-lsd-hp-torque-r160-r180-r200-r230-diff-mount/