How I got Differential Screwed
 

So about a month ago I bought a black 94' to be my daily driver/turbo project.

My plans was to make sure I got a car with a LSD for obvious reasons.

I checked the VIN # w/ Mazda and my original car had a LSD as part of options(im not fam, but I beleive its a C Package car).

I had the car up on jacks because im swapping clutches to get ready for big power, and as its up on stands, I made note that the wheels were rotating the opposite directions. OH NO. Moved them around, and yep, they rotate in opposite directions. sigh

I look at the diff, and it has paint markings all over it, as if it was a salvage item.

Sigh how likely is it the previous owner broke the torsen and swapped for an open :(?

my torsen spins the wheels in opposite directions.

!!!!!

really... because I am just familiar with opens doing that. Shouldnt a LSD lock the other wheel after a spin or 2?

Pull the drain plug and look in there with a flash light. Should be able to see helical gears of the torsen as someone rotates the wheels.

Not sure on the Torsen, but my VLSD spins both tires the same way. The old open diff spin them in opposite directions.

from randy's site

The Torsen won't always turn both wheels when you turn the driveshaft, sometime if they are cold they will. One way is to take out the fill plug to see the Torsen gears which is hard to do because of the angle. Another way for a Type-I is to grasp both halfshafts and attempt to turn both of them in the same direction at the same time (tranny in neutral), can't be done with a Type I Torsen because the torque required to overcome the gear incompatability is too great by just turning the small diameter halfshafts. The The foolproof way is to pull the stub axle on the type 1 or the drive axle on the type two. If you don't see a bar and can see directly thru the diff. it is a Torsen. If there is a bar, (spider gears) it's an open.

I say jsut drive the thing. It's easy to feel the difference between an open and a Torsen. Think about it. If it wasn't easy to feel a difference between how an open rear and a Torsen perform why would we be concerned?

The best way to find out if you have a LSD is to lay a nice patch,if you see 2 lines,then you have a torsen.

+1

need turbo for that first :(

my sticky tires on N/A engine arent doing much for burnouts w/o destroying the car :-D

Will know in about 2-3 weeks :)

Pretty sure mine spin opposite with my Torsen

Mine spin opposite as well.

not true. my open would do that too when I had it.

also from Randy's site: Even the attempt to lay a patch of two black marks on your driveway is not a telling attribute because the Miata is very well balanced and has equal weight on both tires as well as the IRS puts no twisting torque load on the tires either, an open diff Miata will also leave two black marks if you dump the clutch and peal out in a strait line.

If you take some tight spirited turns you should be able to feel the inside tire spinning if it's an open diff.

Torsens do that. I promise--I have at least 3 on the shelf here. :)
My clutch LSD does NOT do that. <3 clutch LSD

yep not hard to feel the difference....turn the wheel to full lock, go wot, you'll know.....

Yup, my torsen does it too...
Best way to test without abusing your car would be a paved surface with sand or small rocks on it, if you turn to full lock and go very slowly, you will feel the inside tire knd of skipping along. it will be obvious.

+1

which I guess means I <4 my clutch LSD

For the definitive answer pull and axle shaft and have a look inside.
Bar = open
No bar = Torsen
Should take only a few minutes to check.

Okay guys, stupid questions, but with a torsen, when you break traction and start laying rubber, you always are going to see two tires marks, right? I ask because when I slide around a corner, I'll see a mark from either both tires or the outside one, yet the one time I did a brakestand only one wheel spun. I have a friend that insisted the car has an LSD after he drove it and he usually knows his stuff but I'm looking for confirmation. I don't understand how a torsen 'locks' so I don't know if the amount of torque going into or age/wear factors in. I've driven a rwd car that has an LSD and mine is no harder to get sideways.