I've had crap luck locating a complete LSD for my FC, I see them on eBay, but every time I buy one(4 times now) I get sent an NA diff. I've also debated on swapping to a Torsen but I'm worried that I'll break the shafts again. I've got a WTB on a few forums , but it's not looking promising, which is not good.

What other options do I have? This car's been sitting for a year, in my dad's garage and, I NEED to get her on the street and back at my place before it starts snowing in MI.

 

ford 8.8" ?

FC Ford 8.8 IRS mounting kit

it's pretty easy to identify a TII vs an NA diff by looks:
http://www.norotors.com/index.php?topic=600.0

there are also a lot of NAs that have LSDs...

 

I've got an S4 available however its kind of a bitch to ship one from California. Do you need the casing as well?

 

Your profile says you have a n/a so do you mean you have received 4 n/a diffs that were not LSD or are you wanting to put a TII diff in your n/a? You can use a Torsen from a Miata(but you'll have to install it in your housing) if you are just looking to put LSD in your n/a. You did mentioned a Torsen. Did you mean you already had one and broke the shafts or that you broke the shafts on your original diff? Also a TII isn't a direct swap. It uses different half shafts and the flange on the driveshaft has a different bolt pattern as the TII used a larger dia. driveshaft.

 

@eage8
Ouch that's pricey. The problem I'm having is that they list and show pics of TII LSD's in the ad's. Then when I get them, I see they aren't the right one's, pop a drain bolt and shove a little inspection camera in them to make sure they aren't the NA LSD's.

@dguy I kept the last open diff that was sent to me in case I needed it, so I'm good, but thanks!

@Dak I had an open diff, and had to launch hard to avoid being rear-ended and, in the process, I broke a stub shaft. I was looking at doing a Torsen swap, and even had one at one point, but I really wanted to swap over to the LSD unit for the larger shafts (Oh Baby!) because I go to AutoX and track day events.

 

The shafts on the n/a LSD aren't any bigger than the shafts on the n/a with an open diff. In fact the 86-88 n/a LSD and all open diff cars use the same stub shaft. 89-92 n/a LSD shafts are a different length because of the viscous LSD. You can't just make the statement you want an LSD for larger shafts as it is an incorrect statement. Using the 86-88 n/a clutch type LSD or Torsen unit from a Miata uses the same stub and half shafts as your open diff. If you want larger shafts you need a complete TII rear end including the half shafts. So instead you should say " I want to swap over to the Turbo LSD unit and rear end for the larger shafts".

As for track days lots of people road race with the n/a rear end because their class rules don't allow swapping to a TII rear. Now in drag racing people break everything.

 

^^^ What DAK said. The NA and Turbo differentials are not interchangeable UNLESS you want to change to a custom driveshaft and install Turbo half shafts.

86-88 NA cars came with open or clutch type LSDs. At this age, all clutch type LSD units will need to be rebuilt. Otherwise it will perform the same as an open LSD. Strength between the units is equal.

89-91 NA cars had the option for the viscous LSD. You could also source a viscous LSD from a first generation Miata. The viscous unit is not much of an upgrade from the open diff. The lockup is minimal at best. Strength of the viscous LSD is the same as the open diff.

The Miata Torsen would be considered an upgrade in both lockup AND strength. When you see a Torsen carrier, you'll understand. The stub shafts are the same strength.

As for autocross? A Torsen is illegal in the stock and street categories. If you're serious about competing, then this might be a consideration.