Automotive marketing loves acronyms. XWD. TCS. EBD. If you are standing in a dealership lot, those letters are likely throwing you for a loop. But there is one specific acronym that matters more for actual driving dynamics than almost any other: eLSD.
It stands for electronic limited slip differential.
It sounds like a mouthful because it is. The name tells you exactly what it does. You just need to understand the “D” part first. A differential is a gear assembly that allows the wheels on a single axle to rotate at different speeds. This isn’t a quirk. It is a necessity.
Think about a track and field race. Runners start at staggered positions. The person in the outermost lane has a head start because their lane is longer. The person in the inner lane starts further back. If everyone lined up side-by-side, the inner runner would have a shorter distance to cover. The race would be unfair.
A car turning a corner is essentially running a track. The wheels on the outside of the turn are in the “outer lane.” They have to travel a greater distance than the wheels on the inside. If the axle forced both wheels to spin at the exact same speed, the car couldn’t turn smoothly. Tension would build up. The result would be either the tires skidding or the driveshaft snapping in half.
Most cars come with an open differential. This is the basic version. It allows each wheel to spin at its own speed. It splits the engine’s torque roughly fifty-fifty between the two wheels. It also transfers the motion from the driveshaft to the axle shafts, which intersect at a right angle. (For a deep dive on the mechanics, check out How Differentials Work.)
This setup works fine for commuting. It fails when you actually want to drive fast.
An open differential sends power to the wheel with the least amount of traction. Slip one tire on ice? Power goes there. Spin one tire in mud? Power goes there. The wheel with grip gets nothing. This is where the “LS” in eLSD comes in.
The next section covers the mechanics of the limited slip differential and how electronics take control of torque vectoring. Stay tuned for the rest of the breakdown.
