Up in the dumps

The folks at Sterling Trucks ought to be pleased with themselves these days, being the first to engineer Caterpillar’s C9 engine into their chassis. I recently had a chance to drive the 8.8-litre diesel, the first of Cat’s line with ACERT emission controls, in a good-looking LT9500 tandem-axle dump truck.

From the peripherals to the overall footprint, the C9 is completely different from the 3126E it replaces (along with the ACERT C7). As such, the C9 was “a clean sheet installation,” according to Sterling chief John Merrifield, requiring a total re-engineering job.

That doesn’t come cheap, but Merrifield is high on this engine. “This should be a pretty good seller for us,” he told me. “We’re glad to have it.” Indeed, it’s aimed at Sterling’s key markets: vocational and regional highway use, and also should find its way into municipal fleets.

For now, the C9 competes with the 8.3-litre Cummins ISC in the Sterling databook (all-new Cummins ISC and ISL engines are almost ready for market; see sidebar). The C9 and ISC are turbocharged, inline-six diesels with replaceable mid-stop cylinder liners, and they both weigh about 1,500 pounds. The C9’s ratings range from 275 to 350 horsepower and 860 to 1,150 pounds-feet of torque. The ISC stretches from 225 to 315 hp, plus a 350-horse rating for fire trucks, with torque between 620 and 950 pounds-feet. The C9 has front and rear PTO capability while the ISC has a rear takeoff only. The C9 costs more due to the ACERT emission controls; the ISC uses older emission technology and does not meet EPA ’02 standards, but it sells without a penalty because Cummins has accumulated “credits” for other engine models that do better than the EPA requires.

The C9 and its brother, the 11.1-litre C11, due in December, will together replace the existing Cat C-10 (that’s not a typo, by the way–Cat dropped the hyphen in its new engine nomenclature). Like other ACERT engines, both need an oxidation catalyst in the exhaust system. But unlike their bigger C13 and C15 stablemates, they use a single turbocharger, and together they cover torque ratings from 860 to 1,350 pounds-feet.

In the Sterling I drove, with a full load of dirt out back and an Eaton Fuller RTO-11908LL in my right hand, the 335-horse C9 felt strong for an engine of less than 9 litres. There’s a long 5-per-cent grade not far from Cat’s proving grounds near Peoria, Ill., and from a rolling stop at its base in second gear I pulled my way up to fifth and held nearly 1,500 rpm to the top. Quite respectable, and I even had some leeway because that model reaches its maximum 1,050 pounds-feet of torque at 1,400 rpm.

My drive was for only a few miles–we take what we can get with these new engines nowadays–but it was enough to show first-rate drivability and decent throttle response. I drove other C9s of various descriptions, all in Sterling dumps, on dirt roads within the proving grounds, and each one felt the same in that respect.

Sterling and Western Star’s general manager in Canada, John Nelligan, Jr., says he’s also pleased with the C9 and even figures to spec the 340-horse model in twin-steer Western Star mixers. That may be a stretch to some minds, but only hours and miles will tell. S

SIDEBAR

Cummins is expected shortly to unveil re-vamped 8.3-litre ISC and 9-litre ISL engine lines to meet ’02 environmental standards. Developed under the code name “Pegasus,” the engines will not use cooled exhaust-gas recirculation; Cummins engineers opted instead to manipulate the combustion process and find a new way to beat down nitrous oxides. Both engines use common-rail fuel injection, and a variable-geometry turbocharger on higher-horsepower models.

The new ISC is pegged as a medium-duty engine while the slightly larger and more robust ISL will be positioned as a heavy-duty motor with its beefed-up valve train and available engine brake. Both will also have exhaust aftertreatment, a common oxidation catalyst not unlike the one used in Caterpillar’s so-called “bridge” engines.

Ratings are not known at this point, but it seems clear that the Cat C9’s real competitor will be the new ISL, not the ISC.