Top dog

| December 12, 2008

The Pinnacle incorporates a new Advantage chassis, which places the engine lower, allowing easier maintenance and a shorter turning radius.

Mack Trucks introduced at a dealer conference its new flagship highway tractor, the Pinnacle, and new models of its Granite and Granite Axle Back construction vehicles.
The truck maker also announced the new MP7 and the larger MP8 engines, which will
eventually replace the present ASET engines.

The Pinnacle closely resembles the Vision and will replace it in 2007. Vision tractors with ASET engines and Pinnacles with MP7 engines both will be available in 2006. Although the Pinnacle’s cab is larger, the most outstanding feature is a wraparound, cockpit-style dashboard that puts all the controls within easy reach, plus a large, centered digital readout screen. The clutch pedal is air-assisted to reduce both pedal effort and stroke.

The Pinnacle is offered in a 116-inch bumper-to-back-of-cab daycab configuration, as well as 48- and 56-inch flat-top, 60- and 70-inch mid-rise, and 70-inch high-rise sleepers. The new Granite and Granite Axle Back models feature a 116-BBC dimension and are built on the Mack Cornerstone vocational chassis.

The MP7 is the first in a new Mack Powertrain family of engines with the same design that will be used to meet the 2007 U.S. emissions regulations. Mack executives say the engine has improved fuel economy – 2 percent to 3 percent in many applications – compared with the ASET engines.

“The MP7 looks, feels and sounds like a Mack,” says Steve Homcha, executive vice president, referring to distinctively high torque rise power and torque curves that have been a trademark of Mack engines since the 1960s.

The MP7’s key components include:

  • High-performance (cooled) exhaust gas recirculation;

  • Variable geometry turbocharger with sliding nozzle ring;
  • Electronically controlled unit injectors;
  • Single overhead cam with four valves per cylinder;
  • Wet/dry cylinder liners with single-piece steel pistons; and
  • Rear gear train that offers a simple rear power takeoff option.
    The 11-liter MP7 will be introduced in 2006. Both ASET engines will be available until 2007.

The 13-liter MP8 will be introduced in 2007. It will feature up to 485 horsepower and torque ratings as high as 1,700 lb.-ft. A third version, the MP10, likely resembling the present Volvo 16-liter, will show up in 2008 with as much as 600 hp, executives said.

The new MP line (the initials stand for Mack Powertrain) is the first completely new engine at Mack in 40 years, said CEO Paul Vikner. It is a distinctively Mack version of a common structural platform that will be shared with Volvo Trucks of North America and Volvo’s European products.

The engine is an in-line six with 660 cubic inches of displacement, a single overhead cam, electronic unit injectors, four valves per cylinder and wet/dry replaceable cylinder liners. The design is optimized for the higher cylinder pressures needed for 2007 and beyond, though its initial versions available in 2006 will be tuned to 2004 emissions specifications. At 2,270 pounds, it is about 170 pounds lighter than the ASET engines.

On-highway and vocational versions of the MP line also will feature the variable geometry turbo and water-cooled EGR used in ASET engines. The 2007 versions will feature a diesel particulate filter, as will their competitors.

Other refinements include multiple injections per powerstroke to ease the task of minimizing soot and NOx emissions. The combustion system of the new engine will minimize oil sooting; as a result, the standard oil change interval will be 30,000 miles.

The MP7 will have three available sets of power curves in six horsepower ratings. The Econodyne ratings are for fuel sensitive highway operations that run loads lighter than 80,000 pounds. The Maxicruise curves are designed for highway trucks that pull maximum loads and run on rolling hills. The Maxidyne curves are for trucks that see severe duty or run off-road.

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