Mack boosts fuel economy under Earth Day backdrop

AUSTIN, TX – Mack Trucks’ choice of the setting and day to unveil a series of powertrain upgrades was no coincidence. Austin, Texas is known for its music and barbecue, but is also recognized as one of the Top 10 greenest cities in the U.S.  And April 22 marks Earth Day.

Collectively, they offered a fitting backdrop for changes made in the name of fuel economy.

The 2017 Mack MP engine lineup will see fuel economy jump between 2.1 and 8.8% compared to today’s models, while a new Predictive Cruise will effectively memorize terrain and enhance shifts when routes are repeated.

Engine upgrades include a common rail fuel system, and turbo compounding that tranforms waste heat into torque on the camshaft.

Fuel-saving enhancements have certainly put the engines on a diet. The common rail fuel system, widely used in Europe, allows for an assembled camshaft that is 27 pounds lighter than its single-piece predecessor. The MP8’s cylinder block is also 44 pounds lighter than today’s models. Even when turbo compounding is introduced on the MP8, the engine is still 33 pounds lighter than existing models.

Turbo compounding on an MP8, when combined with a Super Econodyne spec’ing package and 2.64 axle ratio, can boost fuel economy 8.1%. Choose a 2.47 axle ratio, and the fuel economy could jump 8.8% or higher, Mack says.

This turbo compounding is meant more for fuel economy than adding performance. “We’re taking that 50 hp and letting the engine rest more,” explained Stu Russoli, manager – highway and powertrain products marketing.

One of the most visible changes under the cover of the latest engines is a reshaped “wave” piston that better distributes fuel, increases the compression ratio, and ultimately improves combustion and generates less soot. The fuel itself is delivered through three injectors that are combined with another three units that combine pumps and injectors, all driven off the camshaft. There’s also a two-speed coolant pump that reduces parasitic losses.

The upgrades are not all made in the name of fuel economy alone. A new two-piece valve cover and shimless rockers both promise to speed up related maintenance. And a double-walled Exhaust Gas Recirculation flow sensor will reduce condensation and soot in cold weather, while a new intake throttle will ensure faster warmup times.

The 2017 MP8 can now be ordered, while the MP7 and MP10 engines can be ordered beginning in July. The Mack MP8 with turbo compounding can be ordered beginning in October 2016.


Unlike systems that rely on maps, Mack’s new predictive cruise control memorizes up to 4,500 “events” along the terrain that a truck drives, tracking speed, engine load, weight and road grades. “If you go back to that place again, it will get you better fuel economy,” says Russoli, referring to gains in the neighborhood of 1%. When the underlying GPS recognizes the truck’s location, it can adjust speeds by a few kilometers per hour when heading into a hill, or coast over the crest. Drivers will receive a warning when the system is taking over, so nobody is surprised by an unexpected change in speed.

The company is exploring options with semi-autonomous vehicles, too. “We didn’t rent the Hoover Dam,” added Mack Trucks president Dennis Slagle, in an obvious nod to Freightliner’s unveiling of the technology in Nevada. But offerings are in the works. “We’ll be ready,” he says.


These changes build on related fuel-saving changes introduced earlier this year.

The ClearTech One exhaust aftertreatment system – first unveiled during the recent Work Truck Show — is 11 inches shorter and 17 pounds lighter than today’s systems, and it can also be serviced in half the time because the units don’t need to be dismounted from the chassis when replacing the filters. Even though this introduces more twists and turns, Mack says there are no challenges relating to back pressure.

It’s not for everyone, though, so a two-unit aftertreatment system is still available as an option for vehicles like twin-steer trucks.

This is on top of two new versions of the mDrive heavy-duty automated manual transmission. The HD 13-speed version includes a low reduction gear ratio for easier starting on steep grades or when engines are under heavy loads. A 14-speed counterpart, available only with an overdrive configuration, adds a second ultra-low-speed reduction gear needed when pouring curbs, or when maneuvering heavy equipment at low speeds. Both offer up to four reverse gear ratios.

The mDrive is already the most dominant transmission in Mack Truck models. It account for 80% of the transmissions in Pinnacle trucks with axle-back configurations, and 60% in the axle-forward versions. The so-called “take rate” for Titan trucks is 30%, and 20% of Granite models have them.

“Our goal is 10 million miles (16 million kilometers) of testing before these are actually in production,” Russoli adds of the latest powertrain enhancements.

Recent upgrades are not limited to the hardware, either. Mack Trucks continues to invest in its underlying data systems and processes. Dealers that have made the investments to become Certified Uptime Centers, for example, have seen throughput increase by 17%.

A five-year project to update the Customer Relationship Management (CRM) system used by sales teams is also complete. The changes were “for the prototypical sales manager, not for us,” said Slagle.






John G. Smith is the editorial director of Newcom Media's trucking and supply chain publications -- including Today's Trucking,, TruckTech, Transport Routier, Inside Logistics, Waste & Recycling, and Road Today. The award-winning journalist has covered the trucking industry since 1995.

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