Summer 2002 Forward to a Friend

EVERY SUBARU is designed around the idea that you should be able to get where you want to go quickly, comfortably and safely, regardless of the weather or road conditions. The driving experience should be satisfying and stress-free. This requires a vehicle with exceptional control, and that’s what every Subaru provides.

A key component of the Subaru driving experience is Subaru All-Wheel Drive (AWD). Subaru All-Wheel Drive has been constantly updated and improved for three decades as it has evolved into the state-of-the-art system now in use in every model in the Subaru line. Let’s look at what makes Subaru All-Wheel Drive such an ideal component of the Subaru driving experience.

All-Wheel Drive is a key component of the Subaru All Wheel Driving system. When AWD is combined with a horizontally opposed boxer engine and a four-wheel independent suspension system, the three system components work in harmony to provide exceptional traction, handling, balance and control.

The All-Wheel Drive Difference

There’s a reason why Subaru of America, Inc. only offers All-Wheel Drive vehicles – they work the best under the widest variety of conditions. Subaru has always been ahead of its competitors in regard to drivetrain development.

Understanding The Different Drive Systems

There are three basic automobile drivetrain configurations, and each configuration has its own drive characteristics that set it apart from the others.

FRONT-ENGINE/REAR WHEEL DRIVE: The engine is in the front of the vehicle and drives the rear wheels. Rear-wheel drive vehicles tend to oversteer when the rear wheels lose traction – this means the back end of the vehicle may break free and skid under certain conditions, which may cause a spin. See Figure 1. Vehicles with this drivetrain configuration don’t have the advantage of having the engine weight over the drive wheels to improve traction.

The parent Company of Subaru, Fuji Heavy Industries, is formed.

The first Subaru automobile rolls off the assembly line.

Subaru of America (SOA) is formed.

Subaru introduces the first “On-Demand” four-wheel drive system for passenger vehicles.

47 percent of all Subaru vehicles sold in the U.S. have four-wheel drive.

Subaru becomes the first and only manufacturer to offer four-wheel drive across its entire model line.

The Subaru four-wheel drive system evolves into All-Wheel Drive. The design eliminates the need for driver interaction by automatically varying the amount of power delivered to each of the four wheels.

Subaru offers a 100 percent All-Wheel Drive U.S. model line.

Subaru introduces the Vehicle Dynamics Control (VDC) system.

FRONT-ENGINE/FRONT WHEEL DRIVE: The engine is in the front of the vehicle and drives the front wheels. Front-wheel drive vehicles tend to understeer. Under certain conditions, the front wheels may lose traction, forcing the vehicle to want to go straight – or “plow” – to the outside of a curve during hard cornering. See Figure 2. In general, front-wheel drive vehicles offer better traction than rear-wheel drive vehicles because the weight of the engine and transmission is directly over the drive wheels.

FRONT-ENGINE/ALL-WHEEL DRIVE: The engine is in the front and drives all four wheels. All-wheel drive helps provide more neutral handling, virtually eliminating unwanted oversteer and understeer. See Figure 3. This is the configuration in place in the Subaru model line.

Four-Wheel Drive Defined

Four-wheel drive is not the same as all-wheel drive. There are two basic types of four-wheel systems:

“PART-DRIVE” four-wheel drive systems typically route power to the rear wheels. When the driver goes off-road or encounters slippery conditions, the front wheels have to be manually engaged. Only then is the vehicle powered at all four wheels. These systems can only be utilized properly when driving off-road or in slippery conditions and depend on the driver to engage the system.

“FULL-TIME” four-wheel drive powers all four wheels all of the time. The amount of power is evenly divided among all four wheels.

1. Rear-wheel drive vehicles can oversteer, which may cause a spin.

2. Front-wheel drive vehicles can understeer during hard cornering.

3. Subaru AWD provides neutral handling and balanced vehicle control.


Subaru AWD Defined

Because you never know what’s on the road ahead, Subaru engineers developed Subaru All-Wheel Drive, a system that not only is capable of powering all four wheels, but also automatically varies the amount of power sent to each wheel at all speeds. The result is a vehicle that’s remarkably steady on the road under virtually all weather and driving conditions.
Decades of development by Subaru have led to a system with no buttons to push or levers to engage – it operates without driver intervention. Subaru All-Wheel Drive automatically adjusts power to each wheel to provide the best traction. Subaru All-Wheel Drive automatically transfers power from the wheels that slip to the wheels that grip – this translates into enhanced control and traction when things get wet and slippery. But it also helps improve overall performance even when the pavement is bone dry.

For example, when you brake hard, weight shifts forward, reducing rear traction. Or if you step on the accelerator, the opposite is true. And in a curve, the vehicle dynamics are constantly changing. Subaru All-Wheel Drive varies the amount of power sent to each wheel at all speeds. So whether you’re braking, accelerating or cornering, on dry pavement, mud or snowy roads, traction is there when you need it, with decades of Subaru design and development behind it.

Races of the World Rally Championship (WRC) are held on some of the world’s toughest roads, where Subaru vehicles are most in their element. Subaru began its full participation in the WRC in 1990, and won the Manufacturer’s Championship from 1995 to 1997 with the Impreza WRX.

The advanced automotive technologies tested and proven by Subaru on the WRC help us build better, more advanced road cars.

Participation in the WRC has helped Subaru refine the symmetrical All-Wheel Drive system, which is the heart of every Subaru. The engine, transmission, driveshaft and rear differential are laid out in a straight line. By closely balancing the body left and right and keeping components close to the chassis’ centerline, Subaru vehicles are exceptionally agile, yet extremely stable. The boxer engine’s compact dimensions allow it to be placed further back in the chassis, reducing weight ahead of the front wheels and allowing quicker reaction to steering inputs, and its lower center of gravity significantly enhances stability in turns and evasive maneuvers.