Differentials are more than just devices that allow wheels to rotate at different speeds—they dictate torque distribution, affect vehicle handling, and influence traction response. The Auburn ECTED Locking Differential and the Torsen Electric Locker both combine mechanical LSDs with electronic locking, but their internal torque transfer, mechanical behavior, and dynamic response are fundamentally different. This article provides an in-depth technical analysis of both systems, including structure, torque distribution, locking logic, and real-world performance.
Auburn ECTED
Mechanical Limited-Slip
At its core, the Auburn ECTED uses cone-type friction plates. During normal driving, these plates allow a small speed difference between wheels. When one wheel begins to slip, the friction plates progressively engage, transferring torque from the slipping wheel to the wheel with more traction. The progression is gradual, which smooths torque transfer and maintains controllable slip through corners.
The friction plates’ thickness, cone angle, and material determine the initial engagement torque and the steepness of the torque increase curve. In practical terms, this means that the differential behaves smoothly under moderate torque differences but ramps up quickly as slip increases.
Electromagnetic Lock Logic
The system also incorporates an electromagnetic lock. When activated, it instantly locks the side gears, bypassing the friction plates and creating a rigid connection. This dual-mode operation works as follows:
- Non-Locked Mode: Friction plates handle torque bias, allowing controlled slip during normal driving.
- Locked Mode: The electromagnetic lock forces both wheels to rotate together, instantly delivering maximum torque bias. This can produce a brief driveline shock, especially at low speed or on very low traction surfaces.
Torque Distribution Dynamics
- Low torque difference: Friction plates lightly engage; torque bias is small, allowing some wheel speed difference.
- Moderate torque difference: Plates engage further, rapidly increasing torque transfer.
- Lock activation: Torque bias reaches its maximum instantly; left and right wheels rotate together, friction plates are effectively bypassed.
Driver experience: Smooth progression under normal conditions, followed by a noticeable surge in torque when the lock engages.
Torsen Electric Locker
Gear-Based Torque Distribution
The Torsen differential relies on a network of helical or worm gears. When torque differences exist between wheels, the gears automatically redirect more torque to the wheel with greater resistance.
- Torque bias ratio (TBR) is determined by gear geometry (e.g., 2:1, 3:1).
- Unlike friction systems, Torsen biasing does not rely on wear-prone components, ensuring long-term stability under high torque.
Electromagnetic Lock Function
The electromagnetic lock in a Torsen system is mostly supplemental:
- Pre-lock: The gears have already distributed most of the torque; the lock ensures complete synchronization of wheel speeds.
- During lock: Since the gears already manage torque, the lock engages smoothly without perceptible shock.
- Post-lock: Wheels rotate as one unit; gears continue to provide fine torque adjustment, enhancing durability and stability.
Torque Dynamics and Response
- Non-locked state: Torque distribution is smooth, wheel speed differences do not produce abrupt changes.
- Locking: Engagement is gradual and imperceptible.
- Durability: Gear-based design tolerates high torque loads and remains stable over long-term use.
Conclusion
Auburn ECTED uses friction plates with an electronic lock. It allows gradual torque transfer during normal driving, then locks instantly when needed. This gives strong traction for off-road or slippery conditions but can produce brief torque spikes and requires maintenance of the friction plates.
Torsen Electric Locker uses gears to continuously bias torque toward the wheel with grip. Locking is smooth, predictable, and durable, making it ideal for high-performance road use or mixed driving conditions (both paved and light off-road).
In short: Auburn ECTED is for aggressive traction and off-road situations; Torsen Electric Locker is for smooth, reliable torque control and long-term durability.
