EXPLAINED

TWINSTER DIFFERENTIAL

DANIEL GARDNER

TRICKY TECH IN SIMPLE TERMS

TWINSTER DIFFERENTIAL

MAY 2017

What is it?

A departure from the traditional rear differential that takes torque distribution away from a set of ring, sun and planet gears and hands it over to just two gears and a lighter, more compact pair of multi-plate clutch packs.

The innovation forms part of Holden’s new all-wheel-drive system that will be available under certain variants of the new European-sourced Commodore.

Why does it matter?

Torque needs to be shared between driven wheels for optimum traction and driving dynamics, but traditional systems have limited control over which wheel power is sent to. With improved torque distribution, grip and driving enjoyment can be maximised.

Pack mentality

Multi-plate clutch packs are hydraulically actuated and infinitely adjustable

How does it work?

Unlike a purely mechanical differential, the Twinster solution uses an electronic controller located on the unit, which is connected into the vehicle’s stability systems. Information regarding wheel slip and available grip is monitored 100 times per second and is sent to the controller, which alters clutch slip.

As clutch pressure increases, the locking effect also increases and more torque is sent to the individual wheel.

Operation is similar to a limitedslip differential (LSD) but rather than the two rear wheels being locked together for boosted traction, the together for boosted traction, the Twinster clutches work completely independently for greater control and flexibility.

As a bonus, the independent functioning allows the system to incorporate ‘torque vectoring’ which enhances cornering performance by braking an individual wheel, or apportioning torque to it.