All present and accounted for. And there are a bunch of them, too — Kenworth’s 2008 fleet.

From the Class 6 K260 (launched in March at the Mid-America Trucking Show) to a heavy-spec T800, almost every market was represented when Kenworth rolled the fleet out for a press event held recently at the PACCAR Technical Center near Renton, Wash.

All the trucks were equipped with EPA ’07-compliant engines from Caterpillar and Cummins, along with a Paccar PX 8. We were introduced to the sweet little K260, but the big news was the company’s aero-champ in waiting, the T660.

It was our first chance for a ride in one, so editor Steve Sturgess of the U.S. publication, Heavy Duty Trucking, and I stayed an extra day in Mt. Vernon to put the T660 through a proper road test. That story appears in the current April edition of highwaySTAR and will appear in Today’s Trucking soon. That truck was fitted with Kenworth’s new idle-free cab-comfort solution called Clean Power.

A Quick Intro:

The T660 takes over from the T600 for 2008. As you can see from our lead photo, the changes in the look of the truck are subtle, but given the engineering parameters, i.e., stuffing an ’07 engine under the hood without compromising the legendary aerodynamic shape of its predecessor, the results are dramatic.

The grille is five percent larger to accommodate increased air flow and cooling performance, yet Kenworth is claiming an increase in aerodynamics and fuel economy. The hood is no taller then the T600’s, but it reaches lower to provide airflow through a taller rad. The bumper was reshaped to accommodate the larger grille. The hood is two inches longer than the T600 (122-in. BBC vs. 120 — the extended day-cab version is 128 in. BBC), which is supposed to promote better under-hood air flow.

The step and tank fairings are neatly sculpted to optimize aerodynamics, but they don’t sacrifice durability, functionality, or driver safety. The integrated steps are staggered for ease of egress, and the whole assembly is made of Metton, a lightweight and durable composite material that is said to resist deformation and damage like nothing else.

The bumper is made of the same material, and it’s designed in two pieces to minimize replacement costs in the event of damage to one side only. Kenworth even optimized the placement of the licence plate to reduce drag.

The T800 extended day cab can be configured for dump
service with lift axles and an Allison 6 speed automatic.

Also new for the T660 is an attractive and highly effective headlamp design. New Halogen projector low beams provide 40 percent more light down the road than a traditional sealed beam lamp, and they’re said to last three times longer. An optional High Intensity Discharge type of lamp provides 75 percent more light and is expected to last 11 times longer than a sealed beam, says Kenworth’s chief engineer, Mike Dozier.

And not insignificantly, Kenworth has introduced a spiffy new armrest that swings away behind the seatback when not in use. That leaves drivers 14 in. between the seats instead of eight with the old armrests.

DPF Configurations:

Obviously new for 2007 is the presence of the exhaust aftertreatment device. These, in most cases, take up a little more room than a standard muffler, and in the case of Caterpillar, there’s a return pipe involved that affects the placement of the diesel particulate filter (DPF). Depending on the application, Kenworth offers three placement options: behind the right-hand step under the passenger door; under the sleeper slung from the frame; or a vertical back-of-cab installation.

At seven inches in diameter, the DPF is too large to mount beside the cab.
There are horizontal or vertical discharges available, and both configurations have diffusers to entrain ambient air with the exhaust stream to cool it.

When we drove the T660, we experienced two active filter regeneration events, and honestly, we wouldn’t have known they were happening except that an indicator light on the dash alerted us to the fact. We terminated one event by hitting the off switch, resuming the process a few minutes later. It was quite transparent, and didn’t affect vehicle performance in the least.

Other Notable Rides:

With only a day to experience the full 2008 line up, I couldn’t drive everything, but I did get a turn in Kenworth’s sporty new P&D chassis, the K260. It’s nearly a direct import of the successful DAF (Paccar’s European subsidiary) LF model — complete with a splendid driver compartment and a six-speed fully synchronized manual transmission.

I also had a turn in a W900 highway truck equipped with an EPA ’07 Cat ACERT C15. While not much has changed on the W900 for 2008, it was noticeably quieter than a similar version I drove a year ago. The C15 was much quieter from the outside than the C13 I drove in a day-cab model.

On both Cat engines, the diesel fuel doser used in the exhaust aftertreatment regeneration process has changed from previous versions I’ve seen. It looks like it’s been completely redesigned, in fact.

With two completely new models in the lineup, Kenworth is expanding its market reach — especially into the medium-duty P&D market. We’ll be writing about these new trucks in the months to come. The ’07 challenges appear to have been overcome — and pretty neatly packaged at that.