What's the big deal about an All Wheel Drive Vehicle?
SYMMETRICAL AWD
Symmetrical AWD, comprising of a longitudinally mounted Horizontally-Opposed SUBARU BOXER engine and a symmetrically designed 4WD drivetrain, is the system that Subaru has focused on for the best stability, safety and on-road performance. This unique drivetrain has been at the core of Subaru development ever since the world's first 4WD passenger car was released more than five decades ago. The entire drive system, from the longitudinally mounted Horizontally-Opposed Engine to the rear differential, is mounted in a straight, symmetrical line. The characteristics of the longitudinally mounted Horizontally-Opposed Engine, which can be positioned low in the vehicle, have been maximized to bring the center of gravity as low as possible, and towards the center of the vehicle itself. The extreme performance that this superior weight balance provides works with the outstanding traction of 4WD to limit the chassis rolling and pitching, which occur driving around corners or braking, for maximum stability at all times. The resulting chassis rocks less and ride comfort is increased, making the journey enjoyable for all passengers. Subaru's Symmetrical AWD comes in a variety of different systems depending on the vehicle type and the transmission used.

Effects
of the drivetrain on drivability
In FWD and RWD drivetrains that do not power all four wheels in the way that
AWD does, excessive loads can be applied to the driving wheels. Lateral forces
then come into play when cornering, and a lack of traction can cause the
vehicle to abruptly change direction towards the outer side of the driving
wheels. On the other hand, AWD systems distribute power between all four tires
in a balanced manner. This creates the most neutral handling possible, as there
is no loss of grip in the direction that the vehicle is traveling, even if the
vehicle is cornering. If one wheel starts to lose traction on slippery road
surfaces, the other three driving wheels can provide the required traction to
compensate. Compared to FWD and RWD systems, there is a much greater level of
traction, and therefore safety. At the same power levels, acceleration is also
so much better when there are four drive wheels rather than two. Complementing
this is the Symmetrical AWD that is only available from Subaru, allowing the
entire system to be mounted lower in the vehicle. A low center of gravity is
directly related to more stable vehicle behavior when cornering. These
Symmetrical AWD characteristics ensure more stable driving under a range of
different driving conditions, letting the driver drive with greater peace of
mind. This unique layout is simply miles ahead of others in terms of on-road
stability, whether that be on local streets or the expressway, or varying
levels of rough terrain. "The driver no longer needs to worry too much about
driving, and does not become tired so easily". This is also an important safety
aspect for preventing accidents before they happen.
Active torque split AWD
An AWD system developed exclusively for 4-speed automatic transmission, E-4AT
(with manual mode) and Lineartronic models to maximize the reliable driving
performance of AWD models under any driving conditions. The Lineartronic CVT
(Continuous Variable Transmission) uses a chain instead of a belt-allowing a
greater span of overall ratios for improved performance and efficiency as well
as a faster response to throttle input. The active torque-split AWD system
usually distributes torque 60:40 front and rear, however sensors constantly
monitor the vehicle's condition in areas such as changes in grip of the front
and rear tires or vehicle speed. The electronically controlled MP-T (Multi
Plate Transfer) adjusts torque distribution to the front and rear tires in
real-time to suit driving conditions, as well as the transmission and driver
inputs. This further increases the stability of the AWD system to deliver a
safe and agile driving experience.
Variable torque distribution AWD
An AWD system designed exclusively for 5-speed automatic transmission, E-5AT
(with manual mode) models to provide aggressive, sporty driving with increased
turning abilities all while retaining the fundamental driving stability offered
by the Symmetrical AWD. An uneven 45:55 front and rear torque distribution has
been set for the front and rear tires. Sending greater torque to the rear
wheels can reduce understeer, a trait that plagues 4WD vehicles, when cornering
for smooth and agile handling. Torque distribution is controlled automatically
up to an equal 50:50 front and rear to suit road surface conditions for both
sporty driving and stability.
Viscous center differential AWD
This is an AWD system for manual transmissions with a simple layout consisting
of a center differential and viscous LSD. A 50:50 front and rear torque
distribution is set under normal conditions. This maximizes traction and
provides driving, backed with stability. When the front or rear wheels slip and
traction is lost, or the wheel speed differs between the front and rear axles,
the viscous LSD maintains optimum torque distribution between the front and
rear and distributes power to the wheels with the most traction. It links the
flexible gear shifting of the manual transmission to deliver sporty driving
that always maximizes the available traction.
Why Choose Subaru?
Subaru has some of the most fuel-efficient AWD vehicles in America. How fuel efficient? The new 2012 Impreza and the 2012 Legacy deliver 36 MPG and 31MPG on the highway, respectively!*
But did you know? Subaru Symmetrical AWD is perfect for Florida's wet and rainy roads.
Most people think AWD is just for the snow, but the vast majority (75%) of weather-related crashes happen on wet pavement either during or right after a rain storm.** Making Subaru the perfect car for Florida!
Why Choose Subaru Symmetrical All-Wheel-Drive?
Precipitation creates slippery conditions that require an even distribution of power for maximum traction, instead of the slip-then-grip alternative. Subaru incorporates several core technologies for the most effective response to these conditions. Subaru Symmetrical All-Wheel Drive improves stability and provides a quicker response to wet roads. This is coupled with the Vehicle Dynamics Control (VDC) system, which automatically senses steering and braking inputs to help keep the vehicle on the driver's intended path.
In stopping situations, the Anti-Lock Braking system (ABS) pulses braking power to help prevent wheel lockup. Electronic Brake-force Distribution (EBD) optimizes the distribution of braking force between the front and rear wheels according to how the vehicle is loaded with passengers and cargo. The Brake Assist system helps ensure maximum pressure is applied to the brakes as quickly as possible in an emergency situation.
The combination of these systems help provide a safe and controlled driving experience, even in slippery conditions.
Symmetrical All-Wheel Drive, VDC, ABS, EBD and Brake Assist are standard on all Outback, Legacy, Forester, Impreza and Tribeca models.
Power and Traction
Symmetrical All-Wheel Drive sends power to all wheels simultaneously for maximum traction and acceleration.
In wet and slippery conditions, that power instinctively flows to the wheels with the best traction.
Stability and Control
The balanced design of Symmetrical All-Wheel Drive helps add control through uniform stability. With power being distributed to the wheels with the best traction, it helps you hold true to the path.
Front-wheel drive vehicles generally understeer or push in a turn, while rear-wheel drive vehicles can often oversteer in a turn.
* EPA-estimated fuel economy. Actual mileage may vary
**(Source: Fourteen-year averages from 1995 to 2008 analyzed by Noblis, based on NHTSA data).