- The Washington Times - Friday, May 17, 2002

Despite being copied throughout the auto industry, Subaru's all-wheel-drive lineup has not been outdone by bigger carmakers. The proliferation of crossover utility vehicles, pioneered by the Outback, hasn't kept Subaru from growing and thriving in an ultracompetitive era. In fact, Subaru has attained an icon status and a cultlike following from its pioneering vehicles.

The term "crossover" was coined to define vehicles that fall into a segment between cars and trucks. Crossover vehicles are built on car chassis and offer many advantages over full-blown SUVs built on truck chassis. Handling, fuel economy and ease of entry are but a few advantages crossovers have over SUVs.

Subaru's Outback, introduced in 1994, was the first of the type. Forester premiered a few years later and is a big reason why Subaru has managed to thrive in this segment.

Forester's debut in 1997 created the compact SUV segment. Its sales have grown despite new models from bigger automakers. Strong competition from the Ford Escape, Honda CR-V and Toyota RAV4 hasn't cut into Forester's popularity.

The second-generation 2003 Forester, recently introduced, is not as revolutionary as the original. But it features a dozen evolutionary changes that improve its performance, safety and durability that should help its sales grow in a market that gets more crowded by the month.

Available in two trim levels as the base Forester X and upscale XS models, the Forester's main attraction is its AWD performance. Subaru produces full-time AWD vehicles exclusively and the 2003 Forester actually offers two AWD systems. Both systems work seamlessly. You don't have to push any buttons or move any levers to engage AWD.

All-wheel-drive is not only an advantage on wet and slippery roads, but ensures stability on dry roads. There is less need for steering wheel corrections when you cruise down the road in AWD. The vehicle tracks better and helps negotiate sharp corners more easily than front- or rear-drive vehicles.

The type of AWD in the Forester depends on the type of transmission the buyer selects. With the five-speed manual transmission comes the Continuous AWD. Active AWD comes in Foresters with a four-speed automatic transmission.

Here's how they work:

Continuous AWD uses a viscous coupling in a center differential mounted inside the transaxle case. The viscous coupling contains a series of opposing discs attached to the front and rear output shafts. The discs are covered with silicone fluid. During normal cruising, power is distributed equally between the front and rear wheels.

When a sensor detects slippage at the front or rear wheels, a rotational difference occurs between front and rear discs in the coupling. This action heats and thickens the silicone fluid causing a power transfer from the plates rotating faster (slipping wheels) to those rotating more slowly (the wheels with best traction).

Once the slippage stops, all the discs resume rotating at the same speed. This action happens in fractions of a second and requires no intervention by the driver.

Active AWD uses a continuously variable transfer clutch contained in the transaxle tailshaft.

Transferring power to slipping wheels develops in the clutch plates made of a friction material designed to handle loads generated during power transfer.

If the front wheels begin to slip, a transmission control module initiates an increase of hydraulic pressure on the transfer clutch. This action reduces slippage of the plates and transfers power to the rear wheels.

As the front wheels regain traction, a module reduces pressure on the clutch, increasing slippage of the plates and transferring power to the front.

Forester is also equipped with a limited-slip rear differential that transfers power from one rear wheel as it starts to lose traction to the other wheel.

For instance, if you drive into a curve and weight transfers to the outside wheel, the inside wheel might lose traction. The limited-slip system would then transfer power to the outside wheel because it has more grip, improving traction and handling.

Subaru is planning to expand its crossover vehicle lineup in the next five years. Its parent company in Japan, Fuji Heavy Industries Inc., is an alliance partner with GM.

In a joint venture with the giant U.S. carmaker, Subaru will get a seven-passenger crossover vehicle that will increase its offerings in the segment. This should help Subaru maintain its icon status for AWD vehicles.


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