WHAT'S THE AMAZING DIFF? MAGIC OF ELECTRONIC LIMITED-SLIP DIFFERENTIALS.

THE ELECTRONIC limited-slip differential (eLSD) is one of the greatest pieces of modern automotive magic.

- BY ZACK KLAPMAN

Ferrari F1-2000 Transaxle

A. Also found on some road cars, this setup uses a clutch pack that sits between the output shaft of the differential and the half-shafts to lock the axles or let them rotate independently.

B. This ring engages and disengages the clutch plates depending on the amount of hydraulic pressure applied.

C. Ferrari saved additional space by using a narrow planetary gearset for its Formula 1 differential.

This wonderful contraption allows you to shift midcorner without lockup, helps you turn more quickly, mediates power in slippery conditions, and delegates horsepower to the tires with the most grip every few milliseconds. While the technology is similar to what's used in center differentials and torque-vectoring systems, for the sake of simplicity and space, the focus here is on the compact trickery of an eLSD between a car's driven axles.