well the 1.6 diff finally went out
 

so I boosted the car the other day and all the sudden I heard a loud pop and alot of grinding :facepalm: so I pulled it out today and found one of the gears came apart and destroyed the case and all

so its time for the 1.8 swap and I would really like to get the 3.9 ratio diff. but I was wondering did the come in an lsd model and which cars do I need to look for to find these? from what I found I know they were on the 99 with the 6spd trans but when did they quit using them? and also will these still bolt up to the support bracket that runs to the trans?

also what is considered a half shaft and what are the stubs people talk about?

thanks for the help and the knowledge Seth

Torsen LSDs were optional on all 1.8 cars. You can often judge whether a car had one by looking at the installed options, color, etc. No A/T car had one. Here are some helpful options lists with which you can infer, for instance, that any '95 car painted Merlot Mica (sparkly purple) with a 5-speed also had an LSD:

http://www.miata.net/faq/Miata90-97A3.pdf


The 3.9 was found only on 6-speed NBs.

From '90 through about mid '95 or so, the axles were two pieces. A short "stub" axle that plugged into the diff, and a loner section containing the CV joints and the part that went into the hub.

Here's an early 2-piece axle, without the stub shaft attached:

http://solomiata.com/images/halfshaft2.jpg

And here's the stub shaft:

http://solomiata.com/images/Stub.jpg


Later cars used axles that didn't have the removable section on the end. Here's a pair of late-model 1 pieces axles:

http://solomiata.com/images/singlehalfshaft.jpg

From '94-'05, the axles are freely interchangeable, regardless of whether they're 1 piece or 2 piece. The exception is that the MSMs got a slightly different differential which used different axles. So you can't use MSM axles with a non-MSM diff, or vise-versa.


Good reading:

http://solomiata.com/RingandPinion.html
http://solomiata.com/Drivetrain.html
http://www.miata.net/garage/diffguide/index.html

So how powerful is your setup and how long did your 1.6 diff last?
I'm boosting my car right now and trying to figure out what to expect.
I have read a bunch of threads, but everyone seems to have a pretty different account.

the setup
 

well the car is making 213 ft lbs torque and 205 hp(mustang dyno) at 10lbs boost. now i will saw i have been pretty hard on it since i finished the build went down the drag strip with slicks on it and it was running 8.93 in the 1/8th mile and in order to do so i was launching at 4300rpms so that prolly didn't help any but oh well it should hold once i can get the new one

I have a 1.6 diff for cheap right now if you dont want to spend the coin on the torsen.

dont have the coin but its hard to drive the car in the snow so i can let it sit a couple months while i save it up