Mikey

You forgot the s. http://www.spoonsports.co.jp/

josh3io

A 1-way LSD only is active while you're accelerating. When you are off the accelerator, your LSD will not be active, and thus the benefits for having one is nullified.

1.5-way is particularly active when your on the accel. but let go of the gas pedal and you will find that the effects are very little.

2-way remains active whether or not your foot is smashing the gas or the brake.

AVXs2000

[QUOTE]Originally posted by Mikey
[B]
You forgot the s.

RicePimp

An LSD is a differential that has characteristics of both open differentials and spools. Technically an LSD is a diff that uses mechanical friction to achieve that effect, but anything that isn't always open or manually locked is usually considered an LSD. This includes clutch packs (like posi-trac, trac-loc, salisbury), viscous diffs, torsen and torsen II, and overrunning clutch types. Each has advantages and disadvantages, and none of them is clearly superior. Some of the factors to keep in mind are the bias ratio (the max ratio of torque between wheels), ease of adjustment, operating friction, speed of lockup, complexity, durability, how quickly it can respond to loss of traction, etc.

Josh3io's explanation of 1, 1.5, and 2 way is correct. Basically a 1-way locks only under acceleration, a 2-way under acceleration and brake, and a 1.5-way locks up less under braking than under acceleration. Those classifications are mainly applicable to salisbury clutch packs where torque acting on the differential shaft can separate the clutch faces to gradually lock the output shafts together. Tapered surfaces on the faces of the clutches determine how much effect this has under both driving and engine braking of the wheels. If there is a taper just in one direction then it is a 1 way diff and the angle of the taper determines the bias ratio only in that direction (always acceleration). If there is a taper in both directions of rotation and the taper angle is the same in both the forward and reverse directions then you have a 2-way diff. If the taper angle is different for each direction then you have a 1.5-way diff.

The practical differences are mainly during turn in. A 2-way will tend towards understeer on turn-in, while a 1-way will act like an open diff. A 1.5 way still has a little slip under trailing throttle, but minimizes understeer by not locking as easily.

Here's a good page with some diagrams.

bbsilver

[QUOTE]Originally posted by S2Kguy
[B]You may need new, beefier parts for your LSD if you have a supercharger/turbocharger, but the Torsen (which is the design not the manufacturer, literally means "torque sensing") is the best LSD design in existence.