Think of Subaru and the well-known Symmetrical All-Wheel Drive (SAWD) system will most likely pop into mind. In the company’s 65 years of existence, the technology has remained a core characteristic of the vehicles it makes for more than four decades.
The first instance of SAWD was found on the Leone Touring Wagon in 1972 that made its debut before the 1972 Winter Olympics in Sapporo. At the time, Subaru wanted to emphasise that all-wheel drive systems were durable, dependable and can be mass produced at a time when the technology was primarily found on off-road vehicles.
As history shows, the Leone proved to be a success in numerous markets, spurring Subaru to develop and improve its system further. What resulted was the addition of Active Torque Split in 1985 starting with the Alcyone/XT, a centre-locking differential on the Leone Coupe 4WD RX/II in 1987, and a viscous limited slip centre differential on the first generation of the Legacy in 1989.
Later on, performance-focused models like the turbocharged SVX (1991) featured Variable Torque Distribution (VTD), which was more rear-biased as compared to cars with Active Torque Split. This pursuit of performance was at its most extreme in 1994 when the Impreza WRX STI burst onto the scene with the introduction of the hallowed Driver Controlled Centre Differential (DCCD).
While the system has evolved throughout the years, the general layout has always remained unchanged, with the left and right sides of the drivetrain being completely balanced with equal length half-axles. This symmetry is precisely why the system is named as such, in case you’re wondering.
In all applications, the main goal of SAWD has always been to maximise traction in any given scenario. Unlike other systems that operate mostly in front-wheel drive mode until loss of traction is detected, warranting a switch to all-wheel drive, Subaru’s SAWD remains permanently on and continually monitors all wheels to ensure torque is sent to the wheels with maximum grip.
As a result, the system is capable of responding quickly to changing terrain, providing drivers the assurance that he or she is always in constant control at every turn. With the surefooted stability provided by the system, a smoother driving experience is guaranteed every time. It’s clear that SAWD is an integral part of Subaru’s ethos, and you can find it in almost every vehicle it currently sells.
