Peterbilt's 387 Hybrid

Steve Sturgess
Executive Editor

The Caterpillar C15 engine in a Peterbilt press ride 'n drive had turned out to be a bit of a star. In the broad test drive event at the Texas Speedway last fall, the Cat engine impressed me enormously and backed up comments made by colleague Jim Park after a Cascadia/Cat drive earlier in the summer.

The C15 was very responsive, showed great throttle modulation and made gearshifting a joy. And at the event, the 387 it powered also gave pause. I hadn't driven one in several years and the new dash appealed enormously.

Let's try to get one for a test drive, I said to the Peterbilt marketing folks.

Such is the state of the current marketplace post-January 2007 that they couldn't find a Cat-powered truck in inventory. In normal times it would have been easy, because Cat has traditionally been 80 percent of Peterbilt production, with Cummins making up the balance with the ISX.

But the big yellow engines have been in short supply as Cat has been working to get them ready for prime time. In the interim, Cummins has been making hay at Peterbilt with its ready-for-2007 ISX.

Even Cummins, though, is a little behind for 2007. The regulation calls for a 1.2 gm/hp-hr NOx emissions level. But the ISX has a higher 2.0 g level (allowed by the EPA through credits from the ISB in the Dodge Ram, which already meets 2010 ahead of schedule.)

So, as it turned out, the big yellow test 387 had a big red ISX under the hood, rated 485 horsepower and with an automated transmission under the floor - probably as far from the initial request as you can get. But it turned out to be an interesting and enlightening drive nevertheless.

As for the rest of the 387, it was an low-to-middling spec that included the Eaton UltraShift LEP automated 10-speed and a dash devoid of driver display or navigation system. The latter was no big problem, because I have labored long and hard to come to grips with the Paccar implementation and so far have failed miserably. (And it's not just Petes and KWs. I also could not get an International CXT on the way from Chicago to Detroit ever to admit to being anywhere than on the Chicago Lakeshore.)

But I am of an earlier generation.

As with Peterbilt tests that started out from the factory in Denton, Texas, we headed for the hills - the Texas Hill Country, though this time less to the south. We were running loaded to 75,000 pounds, but in the absence of any dash readouts, flying blind about fuel consumption and average speeds. And in these days of competitive fuel consumption claims, I'm a little reluctant to pull into a truckstop and do a fill-to-fill evaluation over only a few hundred miles. For one, this was a brand new truck. For another, I didn't have what I needed to do the fuel temp corrections and so on that can make such big differences in the final results.

The Truck

The 387 is Peterbilt's wide-cab aero model, sister to the Kenworth T2000 that preceded it - though apart from its cosmetic similarities, quite a different truck. It uses the same door openings and doors, since both are expensive to tool and produce and are better amortized over both Paccar models. And it uses some of the same unusual plastic composite materials in the side walls and the aerospace manufacturing techniques. But look closely and you will see that the Kenworth has a slab side, where the Pete kicks out at the 'C' pillar to make the sleeper stretch even wider. There's a difference in the floor materials, too, that make the Peterbilt a little more conventional in its construction.

But both are incredibly wide - several inches more than, for instance, the Volvo VN. Only the newly introduced Cascadia - a truck specifically designed to maximize interior space through cab width - challenges the Pete 387.

The wide open spaces inside were maximized in the test 387 with a gearshift pad mounted on the dash wing panel. This takes away the shift lever of a manual or any tower-mounted shifter that might impede driver movement out of the seat.

The shifter communicates with a 10-speed Eaton UltraShift LEP. This transmission is optimized for over-the-road applications. We would find it a whole lot better match for the sweet 485 ISX than the pairings we previously experienced in the '07 Kenworths, driven much earlier in the year.

The 10-speed overdrive transmission was matched with Dana rear ends featuring 3.36 ratios and pulling tall 24.6-inch rubber, making this a pretty long-legged truck. From the speedometer and tach, I recorded the engine turning only 1,160 rpms at 60 mph in top gear. Given the 387 is a pretty aerodynamic truck - whatever the competition might argue - it'd have a relatively low engine speed of 1,470 rpm even cruising at 75 mph.

Normally, that might make it a tough truck to drive. But with the automated transmission handling the shifting chores, dropping a gear and picking up 400 rpm whenever it's needed, the 387 is a potentially economical truck that can still get up the grade.

The drive axles were sprung by a Peterbilt Flex Air, the somewhat funky-looking arrangement that has a pair of semi elliptic springs mounted vertically to aid in both springing and locating the axles. Its unconventional appearance is somewhat softened by familiarity, since it is used on both Peterbilt and Kenworth trucks and is gaining in popularity for its light weight and exceptional ride. Up front there were the usual parabolic leaf springs supporting a Dana axle, steered by a TRW gear.

When we get trucks specified by the marketing people, as well as the top-level interiors and the full instrument display, we usually get disc brakes on the Peterbilt and KW trucks. But this was a customer truck, and it came with 15x4 drums up front and 16.5x7 on the drives. Despite their relatively small size, these Meritor front drums give good early bite in response to the pedal. Disc brakes, by contrast, appear to need a pretty hefty shove to get the sort of low speed braking power a driver's used to. On the flip side, you can lean into discs all day long down a grade and never get any fade whatsoever.

Up front, the cooling is optimized on the latest 387, with minimized fan tip clearance to the fan shroud. But somewhat unusually, the 387 goes into 2007 with no new hood. That's a tribute to the original wide-hood design, which has plenty of room to accommodate the additional heat rejection of the increased exhaust gas recirculation in the latest engines. And it's not just Cummins engines that need the cooling enhancement. Cat engines going forward have their own version of cooled exhaust recirculation, which also puts additional heat loads into the radiator.

The real visual giveaway that this is an '07 engine is the special double-walled tops of the stacks to keep the chrome shiny and bright, despite active regeneration events in the diesel particulate filter. On the 387, the DPF sits in the space previously occupied by the passenger-side toolbox.

In The Cab

The door openings are wide, so even though the door doesn't swing to 90 degrees, there's still ample space to get up into the cab, aided by well-placed grab rails inside the cab. This means they stay clean, and it's an easy step on the evenly spaced three steps.

From the seat, there's a commanding view out and to the sides, though it doesn't have the wide open feeling of the new 389, for instance, because the glass area relative to the cabin size is smaller. It does have the benefit of the great cab width in pulling the windshield pillars more away from the straight-ahead vision.

To the sides, the relatively small windows are complemented by good, fully adjustable rigid mirrors to maximize safety in traffic. A neat feature on the driver's side is an ambient temperature readout in the mirror glass, complete with a warning light for near-freezing road conditions.

Exactly the opposite conditions existed during our test, though, with searing heat. It was well contained by the air conditioning, which is capable of pulling down the temperature even in a cab as big as the 387's.

The dash is a nice mixture of the traditional, gauge-filled control center and the more automotive styling of the 389 or Kenworth's new T660 . Putting the shift pad up on the dash has the effect of crowding it a little, even without the availability of a driver information display or navigation system. Nevertheless, it is a handsome setup, with the wood panels attached by easy-access screws to make service uncomplicated.

Aiding the view of the instruments is the low-spoke steering wheel. This actually is derived from the European DAF wheel, and does a masterful job of keeping the main instruments visible. As always, some minor obstruction comes from the rim, but overall it is a very good dash, with switches grouped by function.

Central door lock and window lift buttons are also grouped over to the left on the door pad. Here you find the mirror adjuster, too. Altogether, it's a compact and functional control group.

I found the driver's seat a little short in the leg support department - though, as always, in a short test it's difficult to really explore all the functionality of seat adjusters. Just as an aside, a DVD video to explain to drivers how to set the seat wouldn't be a bad idea. New drivers could pop it into the laptop or the sleeper entertainment system to ensure they get comfortable from the start.

With such a wide cab there's easy access back to the sleeper and, even though there's a generous cupholder, there's no major projection from the dash to get in the way.

There's bin storage on the doors and some overhead in the header, equipped with doors to keep stuff out of sight. Keeping the driver out of sight when stopped for the night, a curtain pulls around the windshield, and there's a separate curtain for the sleeper.

In The Sleeper

The sleeper in the test unit featured upper and lower banks with storage below the high-mount fridge. This included a pull-out desk/table that can be used when you're sitting on the lower bunk. There's a big shelf above the fridge and an entertainment shelf above the big hanging wardrobe opposite. A couple of oddments bins are included in the trim below the upper bunk. The bunk lifts for access to the baggage compartments.

The trim itself is nice and simple, rather reminiscent of a high-series sporting sedan with its fine wood accents. The sleeper is nicely open and airy, with high windows in the roof and side glass to the sleeper walls. Personally, I like the lower windows, especially since the passenger side can give that extra margin of visibility at an oblique road junction. The only downside is having to snap privacy curtains over them when sleeping.

It's worth noting that while this test truck did not feature the option, Peterbilt has a battery storage climate system called the ComfortClass. It is similar to the Kenworth CleanPower, where a package provides for unlimited bunk heating and up to 10 hours of bunk cooling without idling the engine. With increasing restrictions on idling - especially in California, which also legislates APU restrictions - these systems are going to be an important part of an over-the-road truck spec.

On The Road

Despite being a very different spec from the original request, this 387 had a lot to recommend it. The 485 ISX is a great compromise between raw horsepower and good fuel economy, based on previous experience. While higher torques are available, 1,650 pounds-feet provides good performance and pulled the Pete combo well.

The surprise was the Eaton UltraShift LEP. To say we were disappointed with the automated transmissions in other '07-powered trucks we had driven earlier in the year would be an understatement. But this time, the match between the transmission and engine was much more satisfactory. It was completely unobtrusive, as an automatic should be. It picked up the lower ratios smoothly, without the frame-wracking fuss we had experienced before. The LEP is one of a broad range of UltraShifts, and this experience shows that it pays to understand which transmission is going to be the best choice.

As before, we found the transmission required care backing under the trailer, but I discovered that a little foot brake while backing up gave some additional control. Whether this might be a little hard on the centrifugal clutch is a question, but it saves banging into the pin, or in reversing to a dock, thumping the buffers.

Another surprise was how well the tractor turned. I guess the size of the cab suggested the truck might be difficult to get around the corners, but the wheelcut is tight and the turning radius very fair for a 235-inch wheelbase. The steering was also positive, and I had to check to see what gear had been spec'ed on the 387. I always prefer a Sheppard, but this TRW worked well.

Initially I felt the truck was a little noisy, but I guess that's because recent introductions and updates have raised the sound level bar. Putting the meter on the truck showed a creditable 69-72 dB at cruise, and conversation was not impacted going down the road. Even at the full-throttle reading, taken at 75 percent of rated speed in whatever gear gives 45 mph and with all accessories shut off, the Pete was only making 74 dB, so there's not much difference as throttle position is varied. As with all the '07 installations with the diesel particulate filters, noise with the engine brake is very subdued.

Conclusion

The Pete 387 proved to be a truck that would suit a team very well. The performance with the automated transmission was excellent, and the transmission allows for reduced driver skills, opening up opportunities for teams where one partner is new to the driving job.

And the size of the cab means it's possible for two to live without being in each other's pockets.

Some of the newer interior appointments, such as trash bins, back-of-sleeper storage and so on, would be a nice addition. But on the whole, the 387 was very liveable and certainly easy on the eye with its gray trim accented by the wood highlights. And the general driving comfort from progressive braking and on-point steering make this 387 an easy truck to drive.

The spec was a surprise when we climbed aboard this test unit. But in the end it turned out to be a nice surprise, showing you need to be open minded and take care when spec'ing out components in this new, post '07 environment.