Volvo's S60 is no stranger to these pages. Smartly styled, its impressive combination of handling and performance, coupled with a magnum load of comfort and convenience touches, keep this Swedish sedan in constant demand as part of our long-term fleet. It's been much the same story out in the real world, where the S60 hit the ground rolling and never looked back. In its first full season, Volvo's newest offering has made serious inroads into the entry-luxo segment, grabbing market share from European and Japanese competition alike.

Not content to rest on its laurels, the Gothenberg Gang has added a fresh twist to the mix for 2002 in the form of a new all-wheel-drive model, the S60 AWD. In addition to broadening the S60's appeal, this latest adjunct introduces a strain of new and improved technology that will ultimately supplant the existing AWD package throughout its corporate lineup.

The arrival of an all-wheel-drive S60 model is hardly surprising. Sharing the same basic P2x platform architecture with the successful V70 AWD and V70 XC wagons, the S60 was an obvious candidate for this type of upgrade. According to Jay Hamill, segment manager for the car, any lingering doubts were resolved by market research that indicated a solid-and rising-demand for this option. "About one third of the S60 owners we surveyed said that they would buy an all-wheel-drive version if we offered one," Hamill noted.

He also indicated that AWD purchasers would likely be a bit older and even more affluent than the current target owner. Given that the S60 has been attracting hordes of "aspirational move-ups" for the marque-demographically desirable types in their late 30s with a household income of $100K and up-the capability to reach out to the next higher group can only be viewed as very good news.

As might be anticipated, the prime purchase motivations with this buyer segment tend to center on safety, security and peace of mind under all weather and road conditions. Despite Volvo's intentions to emphasize the system's relative strengths in those areas on this initial application, there's plenty of capability in hand for more demanding future fitments. Cases in point are Volvo's upcoming super-high-performance sedan and wagon models due to arrive in 2003 (see sidebar), which will utilize an identical AWD system. Of more immediate and practical import, this second-generation setup allows the fitment of Volvo's DTSC stability system, which is not compatible with the viscous-coupled AWD presently used on the V70 AWD and XC wagons.

The heart of the S60's new Active-On-Demand all-wheel drive is an electro-mechanical package developed by the Swedish firm Haldex. It relies on an electronically controlled/hydraulically actuated multiplate wet clutch pack to regulate power transfer to the rear wheels. Volvo contends this is the most technologically advanced all-wheel-drive system in use today, offering two key advantages over a traditional viscous coupling. First, it can be more effectively integrated into all aspects of the vehicle's existing electronic control systems. Second, it's capable of responding far more quickly to any wheel slippage. Where a viscous link may require up to 3 seconds to fully engage depending on surface conditions, this system begins reacting within milliseconds and can transition to full lockup in only 15 degrees of wheel rotation.

At introduction, the S60 AWD is only being offered in concert with the 2.4T light-pressure turbo engine and Geartronic five-speed automatic transmission. Other system-specific hardware includes the rear subframe and differential from the V70 AWD/XC, slightly stiffer suspension tuning, an upgraded ABS brake controller, the rear-mounted differential coupling/clutch pack assembly and its associated electronic control module. Basic engagement levels are determined using input from the engine and brake ECMs. The AWD system also provides direct feedback to both of these processors, further optimizing its overall operation.

Under normal dry-surface/straight-line driving, output bias runs about 95/5 percent front/rear. As traction conditions begin to deteriorate or the road gets more serpentine, that ratio can be shifted up to a 50/50 mechanical split. The system remains fully functional even when the transmission shifts into overdrive. As with Volvo's other AWD package, it immediately decouples any time the brakes are engaged, returning the car to a basic front-drive configuration.

By Bob Nagy
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