The difference between 1.5-way and 2-way limited-slip differentials (LSD) refers to the behavior of the LSD under different driving conditions.
1.5-way LSDs: In a 1.5-way LSD, the torque bias ratio is different during acceleration compared to deceleration. During acceleration, the LSD provides a greater torque bias to the wheel with the most grip, helping to improve traction. During deceleration, the LSD allows the wheel with the least grip to spin faster, helping to reduce understeer.
2-way LSDs: In a 2-way LSD, the torque bias ratio is the same during both acceleration and deceleration. This provides more consistent behavior in all driving conditions and is generally favored by more serious performance enthusiasts and professional drivers.
It's important to note that the torque bias ratio of an LSD can be adjusted to suit the driver's needs, but the basic behavior of the LSD (1.5-way or 2-way) cannot be changed.
Ultimately, the choice between a 1.5-way and 2-way LSD will depend on the driver's needs and preferences. If you're looking for improved traction and stability in all driving conditions, a 2-way LSD may be the better choice. If you're looking for a balance of improved traction and reduced understeer, a 1.5-way LSD may be the way to go.