Pinnacle of Performance

Steve Sturgess | June 01, 2012

Cover Story

Mack’s on-highway truck proves during well-rounded workout that it deserves its lofty name

 

In Europe, manual gearshifts dominate the passenger car field, but nearly all heavy trucks have automated gearshifts. Here in America, virtually every car is an automatic, while trucks are still shifted manually. That looks like it will change — and soon — likely led by the European makers.

In North America, Volvo is currently delivering 40 percent of production with its I-Shift automated 12-speed, which is an excellent, intelligent transmission. And partner company Mack is now delivering better than 40 percent automatics on Pinnacle highway trucks. Mack’s mDrive is like the Volvo I-Shift: an automated 12-speed that is smart and slick and that makes every driver a star performer.

That’s the conclusion I reached after driving the Mack Pinnacle from the Mid-America Trucking Show in Louisville, Ky., to Mack’s Customer Center in Allentown, Pa. — a distance of about 700 miles that crosses the rugged West Virginia mountains en route. We pulled a loaded flatbed test trailer weighing nearly 80,000 pounds across Kentucky, West Virginia, in and out of Maryland and then across Pennsylvania to Allentown. I shared the driving with David McKenna, a 32-year Mack veteran.

We planned to drop off the Pinnacle at the newly commissioned Mack Customer Care Center in Allentown, which used to be the technical center with its own test track. With the 2009 move of Mack headquarters to the splendid Volvo campus in Greensboro, N.C., the center has become a place where customers can go to see Mack history, experience Mack products — and drive the Pinnacle and its mDrive transmission for themselves.

The Pinnacle is not new. In fact, it goes back to the launch of the Vision in 1999 and, in its basic cab structure, back to the launch of the Mack CH in 1988. But the Vision was a complete redo of the earlier truck with more room for the driver, a total aero package and the “M” shape to the grille.

The Pinnacle was introduced in 2006 to coincide with the launch of the MP engines as the truck and engine combination that would meet the upcoming 2007 emissions regulations and, more importantly, carry through the Environmental Protection Agency’s 2010 emissions standards into the next decade.

It’s Mack’s highway tractor with all the aero aids optimized. In fact, at the 2011 MATS, Mack Product Marketing Manager Jerry Warmkessel said the Pinnacle had been through the National Research Council wind tunnel in Ottawa, Ontario, and delivered a 6 percent gain in fuel savings. Further, Warmkessel said the combination of aero improvements and intelligent mDrive transmission with the new Selective Catalytic Reduction (Mack calls it ClearTech) emissions reducing technology could offer fuel savings greater than 12 percent over previous highway models.

And there’s a newer introduction — a low-rpm cruise package called the Super Econodyne debuted at this year’s show. Gearing so the truck cruises at 65 mph and 1,160 rpm means another potential 2 percent gain in economy for the right applications.

THE TEST VEHICLE

The Mack Pinnacle I drove featured the Mack MP8 at its highest rating: 505 hp with 1,760 lb.-ft. of torque. It’s the 13-liter version of the overhead camshaft engines developed to meet 2010 emissions regulations. Though the MP8 is basically the same engine as the Volvo 13-liter, the Mack has its own personality — in this case, the Econodyne profile, which has long been part of the Mack brand. A feature of this profile is EconoBoost, an on-demand torque boost when the full throttle is held for 3 seconds. The engine adds as much as 200 lb.-ft. at any speed from 1,300 rpm.

It takes an intelligent transmission to account for that. And that’s why the mDrive has to be so different from the I-Shift of Volvo-branded trucks.

The mDrive has common mechanicals with the automated Volvo I-Shift, which is used in Volvo trucks in Europe and around the world, including here in America. But mDrive is by no means the same transmission. In its Mack persona, it has all new programming to match it to the Mack engines, which have far different power and torque curves.

As I climbed into the truck, I noticed the absence of a gear lever and a clutch. I also noticed the shift pad on the wing dash, and with neutral selected, I fired up the engine and we were on our way.

PERFORMANCE

Threading my way out of the Kentucky Fairgrounds, I was impressed by the way the transmission picked up gears yet idled easily in traffic. Adjusting to this vehicle was no problem because the seating provides an excellent view over the sloping hood, and the well-placed mirrors complete the comprehensive visibility. Once on the freeway on-ramp, I hit the throttle to get up to speed — a simple task with the automated transmission. I dialed in the cruise control and sat back to enjoy the ride.

The mDrive is impressive technology. It doesn’t just respond to the engine; it drives it. Gears are selected according to road conditions — the transmission even has an inclinometer so that it knows if the truck is going up or downhill. It knows what the driver wants through the throttle position, and it tells the engine what is needed. Starting out, it gradually closes the clutch for an impeccable response to the first squeeze of the throttle pedal. When it’s time to shift gears, the transmission commands the engine to back off and break the torque flow. The transmission then float-shifts to the next gear, exactly matching engine revs to smoothly swap gears.

In an upshift, the transmission may call on the engine brake to slow the rpms, snapping shifts through faster than even the best driver could. I found this out first-hand at the Customer Care Center test track on day two when accelerating up a 10-percent test hill from a standstill. The Mack just picked up gears as it accelerated away, block shifting one to three, then four and five to make the most of the transmission’s capabilities.

On the highway, such an extreme start was never necessary, but the transmission would often skip gears, either to make the most of the acceleration or to bring in the Powerleash engine brake for maximum retarding. At the same time, it optimized fuel economy. One of the big pluses of all automated transmissions is that they go a long way to equalizing the driving performance of different drivers in a fleet. It’s often said that the difference between a top economy driver and the worst may impact fuel use by as much as 30 percent. With an automated shift, this can be reduced to only a few percentage points.

As we started out, the numbers on the dash display climbed to a very creditable 7.3 mpg as we negotiated the hills of Kentucky. Then as we got into the serious climbs of West Virginia into Allentown, fuel economy crept back to 6.9 mpg. But that’s not at all bad given the heavy load and the mountains.

We started out mid-morning and took a break after four hours. Then, after lunch, we climbed back into the truck with another eight hours ahead of us through the mountains. A cup of coffee at the Pilot Truck Stop on Greencastle Pike in Hagerstown, Md., boosted my energy, and I pulled up at the Customer Care Center gates feeling fresher and more alert than I had at the lunchtime stop. That says a lot for the Mack and speaks well of the transmission. With the task of shifting handled automatically, I was far more relaxed through the drive and less physically tired than I would have been wrestling the shift lever as we journeyed through the mountains.

What’s really nice is the way the mDrive handles the unexpected, like a car slowing in front of the truck or an obstacle in a corner. As a driver, you can deal with the situation, confident that when you walk on the throttle again, you’re going to be in the right gear to step smartly off again.

COMFORT

The Pinnacle has good driver’s seat travel and an adjustable steering column, so it’s easy to set the driving position to the pedals and get the wheel just right. The dash is excellent, with top gauges shaped to fit within the arc of the wheel. So with a great view out and information clearly displayed, it really was a cruise with the transmission dropping gears on the long climbs — sometimes one, sometimes two, almost never three — as the Mack MP8 really gets down and goes, especially with the boost feature.

With the task of shifting handled automatically, I was far more relaxed through the drive and less physically tired than I would have been wrestling the shift lever as we journeyed through the mountains.

The driver display is a triumph. The screens are clear and well organized. Moreover, the column stalk has only an up/down rocker, and the enter and escape buttons are so intuitive anyone can use them within seconds.

The leather seats sit nicely far apart in this wide cab, so even with armrests there’s a full 14 inches of walk-through to the sleeper. However, because the center console stack has big cup holders, a handy shelf and a large storage bin, the seats have to be pushed back when standing up from either the driver or passenger seat.

There’s the usual storage in the header and rather stylishly trimmed door pockets. The cab floor had a thick, fitted-rubber mat that no doubt contributed to the low noise levels in this Pinnacle. We spent no time in the sleeper since this trip was all about getting the truck to Allentown as quickly as possible, while experiencing the Pinnacle’s drive and comfort. However, a quick peek revealed useful shelves that would accommodate duffels and sleeping bags fitted high on each side with a provision on the passenger side for a television and other electronics. Beneath this is a wardrobe, and there’s copious storage under the bunk.

OPERATIONS

The driver display is designed to give the driver, technician and owner all the necessary information simply and intuitively. I had assumed, because the control stalk was the same as Volvo’s, that the rest of the system would be too, but it’s an entirely different interface and it’s even easier to use than Volvo’s.

Mack’s gold bulldog hood ornament is indicative of a Pedigree Powertrain — engine, transmission and rear axles all from Mack.

Other factors that will appeal to drivers are back-of-cab access via the driver-side steps. I was surprised the cab access was not as convenient, lacking a low-mounted grab handle at the hinge side of the door opening.

Engine access is good, even with the added complexity of today’s EGR systems. In fact, the new engines are considerably cleaner, externally, than the earlier E7, and components that might need service are easily accessible.

Scan this QR code or visit http://www.truckersnews.com/testdrives to view a photo gallery of this truck. Find a QR reader in your device’s app store.

 

 

Rawhide option for tradition-minded owner-operators

The Mack Pinnacle Rawhide edition brings an additional level of high style and comfort to the Mack Pinnacle Axle Forward model, resulting in a boldly distinctive truck.

Drivers who prefer traditional styling appreciate Mack’s Rawhide edition of the Pinnacle. Identical in all mechanical respects, the Rawhide has a set-forward front axle and a new hood to get the more aggressive, tall-fronted appearance.

Introduced in 2008, the Rawhide features extra chrome in addition to the big square grille. A Texas-style bumper, undercab and sleeper stainless panels, big stainless visor and four chrome air horns all add to the Rawhide’s luxury. Stylized chrome heated and lighted mirrors — each mirror with a raised bulldog emblem — make a Mack statement.

The 7-inch bullhorn exhaust stacks mount between cab and sleeper in the established “large car” position, making the Rawhide unique in the Pinnacle lineup. Other models mount exhaust at the back of the cab.

The Mack Pinnacle Rawhide edition has a luxurious and extremely comfortable interior, highlighted by a choice of rich colors and soft button tuck UltraLeather.

“The Rawhide edition combines classic styling with all the technology benefits of the Pinnacle model and the next generation of luxury and comfort,” said Mack Product Marketing Manager Jerry Warmkessel at the truck’s original launch at the Mid-America Trucking Show in 2008. “This is definitely a truck that will draw attention.”

Warmkessel added in a recent interview that “fleets are looking toward the Rawhide as a ‘rewards’ truck. Drivers who lead in company contests for fuel economy or personal performance get to ride high and mighty in the Rawhide.”

The truck is available in three cab configurations: 60- and 70-inch midrise sleepers, plus daycab.

The Rawhide interior features soft, luxurious button-tuck Ultraleather and two-tone embroidered seats, complemented by a sleek dash housing Mack’s Co-Pilot driver display. Interior color choices are Slate Gray, Vintage Oxblood, Deep Copper and Classic Buckskin. Accent strips on the cabinets match the dash panel’s brushed nickel. The two-toned pattern in the seats is continued in the sleeper in button-tuck. The cab headliner has four-point lighting, serving both the driver and passenger.

 

Powering the Pinnacle

The MP8 is the 13-liter engine in Mack’s lineup, which also includes the MP7 and MP10. The numbers derive from the displacements stated in cubic inches. So the MP7 (11-liter) is actually about 670 cubic inches, the MP8 is 790 cubic inches and the MP10 (16-liter) is 970 cubic inches.

All are single overhead camshaft engines with the camshaft drive at the rear of the cylinder block. This allows the fluctuating loads from the injector lobes on the camshaft to feed directly into the flywheel rather than along the length of the crankshaft, thereby reducing torsion in the engine and improving injection timing performance.

The MP8 at the 505-horsepower rating has a power density of 38.8 hp per liter. At this rating, then, the engine is several hundred pounds lighter than similarly rated 15-liter engines. Torque rating is 1,760 lb.-ft.

All MP engines are available in three engine families: Econodyne, MaxiCruise and Maxidyne.

The Econodyne personality is mapped for typical interstate applications with extended times at engine cruise speed — part-load, part-throttle applications where fuel economy is a priority. The MP8 in the Pinnacle I used in the drive test is an Econodyne and is very much the highway tractor.

The MaxiCruise engines perform best on rolling interstates in on- and off-road applications and are well-suited to vocational applications. Maxidyne engines provide high power for low-speed, high-performance and severe-duty conditions, especially off-road.

Econodynes use an intelligent torque management strategy called EconoBoost to provide extra muscle to keep vehicle speed constant under full engine loads and to avoid downshifts. Initiating at 1,300 rpm with the driver maintaining speed for three seconds of full throttle (while in the top two gears), EconoBoost provides up to an additional 200 lb.-ft. of torque for as long as needed, allowing the engine to stay in a higher gear to crest a hill or make a safe pass.

Backing up the MP8 engine is the mDrive transmission available exclusively in the Pinnacle. It’s a 12-speed, two-pedal automated mechanical transmission with a base torque input capacity of 1,920 lb.-ft. The mDrive is designed to integrate seamlessly with the MP7 and MP8 engines, and the gearshift is operated by an intelligent shift pad. The mDrive continuously monitors changes in grade (both up and down), vehicle speed, throttle position, acceleration, torque demand and combined vehicle weight.

 

Mack Pinnacle Axle-Back test vehicle specs

Frame: Mack, 266-by-90-by-8 mm

Engine: Mack MP8 505C 13-liter, 505 hp, 1,760 lb.-ft. torque

Engine brake: Mack Powerleash

Transmission: Mack mDrive tMD 12AO automated mechanical 12-speed overdrive

Wheelbase: 233 inches

Front axle: 12,000-pound dual taper-leaf suspension

Front tires: Bridgestone R280F, 295/75R22.5

Rear axle: Mack S40C, 40,000 pounds, 3.25:1 ratio

Suspension: Mack 40,000-pound air-ride

Rear tires: Bridgestone M726 EL, 295/75R22.5

Wheels: Alcoa 8.25-by-22.5 hub pilot, outside polished

Fuel tanks: Dual 140 gallons polished

DEF tank: 23 gallons

Fifth wheel: Fontaine air slide

Seats: Mack proprietary UltraLeather

Interior: Grand Touring

Other: Mack 70-inch mid-rise sleeper; roof fairing, skirts, side extenders; exterior sun visor; heated, motorized mirrors; remote keyless entry; AM/FM/CD weatherband radio w/ iPod interface; automatic temperature control HVAC; daytime running lights; 160-amp alternator; Borg Warner on/off fan clutch; gear reduction starter; Davco 482 fuel/water separator

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