I have no idea what they are, and I don't think I've got one.

Benefits? Losses?
School me on the logisitics of them

 

it means that both wheels will deliver power to the ground
in a open rearend only one wheel does.
if you can spin your tires, then if only the left one spins its a non posi, if both tires spins then its a posi


Wade

 

Benifits.. both tires are delivering power for better traction and acceleration.. losses.. none.. except for cost?

 

How much am I looking at to purchase one? What are the components I need to be sure it comes with?

Im not sure how many Im spinning lol, but I don't think Ive got one. (94 Z28 A4 Conv)

 

All Z28s had them

 

See that G80 on your RPO code sticker? That's for the posi.

 

"Technically" the 4th-gen "posi" diff isn't really a "posi" (short for Posi-traction). That was GM's old school diff that had clutch packs and springs to hold the axles from spinning at different speeds.

The diff(s) that came in 4th-gens are referred to as "limited slip", and while a posi is also a form of limited slip, the newer ones weren't posi.

Anyway, there are 2 types that came in 4th-gens: the Auburn and the Torsen (<--Torsen is short for Torque Sensing). The Auburn is VERY similar to a posi ... it has springs pushing against the spider gears, much like a posi diff had, but there are no clutch packs, just "cone shaped" spider gears that have grooves cut in the back that (as far as I'm aware) build up hydraulic pressure if they start to spin fast, which is supposed to keep them "locked" together so that both axles turn the same speed (my explanation of that may be a little off?? ).

The Torsen is a bit of a mystery, but all I know is that it uses a series of worm gears inside, driving between/across other gears that allow slippage between the two axles, while also attempting to keep the axles turning the same speeds. Unlike a posi or an Auburn, whose friction surfaces and springs can eventually wear out (rendering them useless), a Torsen will always work the same, until/unless it breaks.

AFAIK, most, if not all LT1's came with Auburn's, then GM started putting Torsen's in throughout the LS1 years, but the Auburn was then a "performance option"?! I don't know how to check/find out the stats on that part??

Hope that helps you out a little??

 

True. I have a posi though

 

GM calls it "AXLE POSITRACTION, LIMITED SLIP", so whichever you use, it will suffice.

 

Its true that the rear wheels actually spin in opposite directions correct? I remember when my buddies car was on the lift the last time i spun the wheel just to see if anything was scrapeing against anything rotor and calpier wise, and noticed the other wheel was spinning the opposite direction wile this was going on. Now, its true that posi's make the wheels spin both the same direction correct?

 

Right. A true "Posi" will try to keep both axles "locked" (via friction/spring force) together. An open diff, the wheels will turn opposite directions if one of them is turned.

Now the Auburn type works like a posi, BUT, if I remember correctly, my Torsen diff (factory from the '02 w/2.73's) actually ACTS like an open diff?! If I turn the left wheel forward, the right wheel will turn backwards, BUT, on the streets, they work together! ("limited slip")