Western Star introduced several product improvements targeted toward the vocational market, including EPA ’07 enhancements, an upgraded MBE 4000 engine, Detroit Diesel Tier III off-highway engine emission ratings for 100% off-road trucks, high-strength, reduced-weight frame rails, and body builder-friendly aftertreatment device packaging for vocational applications.

As a result of the new emissions standards, Western Star’s radiator packages have expanded. Available in sizes ranging from 1375 to 1875 sq in., these radiators offer increased cooling capacity for high-horsepower applications and offer the additional benefit of optimal fuel economy as a result of reduced fan-on time. Material options include lightweight aluminum for on-highway applications and copper brass for vocational applications.

In order to accommodate these larger radiators, Western Star added a drop-front frame casting for the axle configurations on the 4900 FA, 4900 SA, and 4900 EX models. This allows for increased cooling capacity without exterior modifications to the traditional Western Star hood and grille.

Accommodating increased radiator sizes has also allowed for improvements in front suspensions. A 56-in. asymmetric spring provides improved roll stiffness and better handling in turns due to a shortened front length while maintaining soft ride characteristics from the longer rear length. Plus, new steering gear and optimized geometry improve road feel, overall wheel cut, and turning radius, the company says.

Western Star has added two 18,000 lb steer axles to its vocational axle offerings. Intended for rugged vocational applications, they provide weight and cost savings as compared to 20,000-lb axles. Both the Meritor MFS-18-133A and the proprietary AF 18.05 are now available on the 4900 FA, 4900 SA, and 4900 EX models.

On the engine front, the MBE 4000 has been upgraded to include a maximum torque rating of 1650 lb ft. Aimed at weight-sensitive vocational applications, its optional premium braking system has been improved by providing an additional 42 hp.

The Western Star 6900XD will be offered with a Tier III off-highway emission-rated Detroit Diesel Series 60 Engine. The engine will be ideal for 100% off-highway applications such as mining, quarry, and off highway construction. Tier III engines don’t require the aftertreatment devices (ATDs) that are associated with the on-highway EPA ’07 emissions regulations.

A body builder-friendly ATD package has been developed for Western Star 4900 FA, 4900 SA, and 4900 EX models. The ATD system – combined with air tanks — is neatly packaged under the passenger-side cab access steps. Offering a cab-mounted vertical tailpipe, the system is protected by an integral diamond plate cover and allows for clean back-of-cab access. This under-step ATD is ideal for vocational applications that require right-hand transmission PTO access and auxiliary transmissions.