First off, the car is imported from Japan and has a lot of goodies. I would believe the car had a track purpose since it's been turbocharged, suspension has been stiffened and it has a lot of goodies (lightweight weds sport tc-05, hks oil cooler, brake cylinder brake etc..). I removed the differential today and I could clearly tell it had been already done on the car. As people say my casing looks more like an open diff, I wonder what LSD unit is in it since I know for sure it is not open.

I wonder if this is an automatic 1.8 diff, square flanges and no rubber dampener.
And maybe the PO put an LSD in it...

edit: how do you know for sure that its not opened?

I'll try to open it up tomorrow we'll see...

I know for sure it doesn't have an open differential. Otherwise, the tail of the car wouldn't be that happy.

http://www.youtube.com/watch?v=ezjxhU8C71s

It would be more prone to oversteer with an open diff...

More oversteer with open diff ? WTF is going on here

Definitely open diff.

UPDATE: I just finished opening the housing, here is what I found. Does anybody recognize this ?

http://img651.imageshack.us/img651/5...c01685h.th.jpg
http://img231.imageshack.us/img231/3...01692ao.th.jpg
http://img28.imageshack.us/img28/6527/dsc01686aq.th.jpg
http://yfrog.com/judsc01687jzj

Open 1.6 differential. Compare:
http://cgi.ebay.ca/Mazda-Miata-OPEN-...item439dc47946

http://thmb.inkfrog.com/thumbn/btdtr...11_004.JPG=600

Actually, turn yours over and take a picture for me.

Sort of looks like this one:
http://j-trade.cranky.jp/IMG_P3461.JPG
http://cgi.ebay.ca/JDM-Miata-T2-Tors...item20b1e82eff

Maybe the housing comes from an open diff but the LSD unit does not.

This is a torsen in the foreground.
http://www.flyinmiata.com/projects/O.../OTC_diffs.jpg

I still think its an auto 1.8 diff

are they supposed to fit in 1.6 casing?

I think its the casing as well.
The auto 1.8 diff had no rubber dampener, and the axle flanges were square, with no ears.
Unfortunately, they were all opened diffs from the factory, but on the positive side, at least it wont break as easily as the 1.6 diff.

Full Tilt I think there is a bit of misunderstanding let me clarify...
All the pictures I've posted are from MY differential which I think happens to be somehow broken (that's why I took it out).
Another thing people don't seem to understand is that my car is very tail-happy (you don't have to fight with the car to induce oversteer, the diff seems to lock easily) IMO that eliminate the possibility my diff would be open and as you can see on the pictures it cannot be VLSD since there is no friction plates. I am no expert but this is what I assumed having read everything I could find on the web.

Still need to know.... what is this LSD
http://img231.imageshack.us/img231/3...01692ao.th.jpg

When an LSD locks, it causes understeer. An open diff will allow the car to oversteer much more easily.
I drove a 01 miata with an open diff and my own 99 miata with an LSD on the same day on the same autocross circuit, and the 01 was much more prone to oversteer, while my car was prove to understeer. I was also a bit faster in my car even though he had better tires, which can be attributed to the LSD.

Im assuming that you think that an LSD causes oversteer because of drifter influence, but thats just a misconception spread by drifter fan boys. The reason drifters use LSDs is because they are inducing oversteer through power, not by normal means of suspension tuning.

Errr... I'm no expert, but I don't see the logic behind that.

Whatever who's right ..(rider384 i agree).. what is this LSD unit ?

Yah, I have no idea what Im talking about. Im just making this shit up as a joke.

He's right. When you turn in, in order for the car to rotate you need the rear wheels to rotate at different rates - hence the need for a differential. Look at racing karts - the only way to get one to turn is to twist the chassis and lift the inside tire up. 2-way LSDs lock up the rear wheels on deceleration as well as acceleration, inhibiting turn-in and causing understeer. This is why most good racing LSDs (OS Giken, etc.) are 1.5 way, providing full lock on acceleration and a little bit of stability on deceleration, but not enough to make the car understeer.

Open diffs will not inherently cause oversteer, but a good LSD will make the car much more stable under hard braking and trailbraking while still allowing for smooth, easy rotation.

OP, even if that is a clutch diff (Mazdacomp makes one that's very common in the SM world), it doesn't really matter because what breaks in the 1.6 diffs is the ring and/or pinion. You can't transplant your diff into a 1.8 housing, either. Even if that is a $2000 LSD made of solid gold, your best bet is to sell it and buy a 1.8 Torsen (or a 1.8 open diff and install an OS Giken).