Driving the New Caterpillar C9

By Tom Berg, Truck Editor | September 28, 2010

Caterpillar's C9
Most of Berg's driving was in this LT-9500 10-wheeler, which was loaded to the rails with dirt. The C9 propelled it well, but most drivers will prefer a bigger engine.
Caterpillar's C9 engine
Midsize in displacement and weight, the 8.8-liter, 1,500 pound C9 snuggles easily under the hood of a Sterling LT-9500. The new engine has heavy-duty components for long life.
Caterpillar's C9
A catalytic converter-muffler on this Sterling is frame-mounted, allowing stack to be a narrow tail pipe. It's one of several exhaust configurations available with Cat and other engines.

Heavy truck operators wanting to reduce tare weight by running a smaller engine now have another choice: Caterpillar's C9, a midrange inline-6 with heavy duty features, and the builder's first ACERT model.

The C9 is in the same class as Cummins' ISL and International's DT530, and like them saves hundreds of pounds and thousands of purchasing dollars compared to larger-bore models. Virtually all the weight savings can be converted to extra payload, and the husbanded money can be left in the bank.

Production of industrial C9s began last year and truck versions were launched in January. Sterling Truck was the first to install one, partly because Cats have been so popular in its L series and because it sells a lot of "Baby 8" trucks. Sterling executives recently showed off the engine and its trucks to customers and the press at Cat's proving grounds west of Peoria.

In Cat's lineup, the C9 falls between the midrange 3126E (soon to be ACERT C7) and the heavy C-10 (succeeded by the ACERT C11). The C9's dry weight is approximately 1,500 pounds, about 100 more than the 3126E and 500 less than the C-10. It has heavy-duty features like wet liners, a four-valve cross-flow head, big rods, crankshaft and bearings, two-piece articulated pistons and ADEM III electronics, among other things.

A C9's 8.8-liter (537-cubic-inch) displacement could classify the vehicle it powers as a Baby 8—a Class 8 truck with a midrange power train. But output is a grownup 275 to 400 horsepower, with torque of 860 to 1,100 pounds-feet. Twenty-five years ago, it took a 14.6-liter (893-ci) Cat 3406 or a 14-liter (855-ci) Cummins NTC to get that much performance.

Old-timer thoughts like those ran through my mind as I drove an LT-9500 10-wheeler along access roads and out onto nearby Interstate 74. Like the other demo trucks, this one's C9 had a 335-horsepower/1,050-lb-ft. rating and ran through a low-low 8-speed, specifically, an Eaton Fuller RTO-11908LL.

John Crowcroft, Sterling's marketing manager, had gotten the steel dump body loaded to the rails with dirt, and we figured we weighed 54,000 pounds and maybe more. The C9 had to work to get us up to 60 to 65 mph. On gentle upgrades, I kept my foot in it and occasionally downshifted, but otherwise enjoyed the ride.

A C9's operating range is 1,400 to 2,100 rpm—pretty much like an old big-bore diesel, and 100 to 300 rpm slower than a 3126E. At first I kept it wound up to use the horses. But I found that on the slight slopes, its torque at lower revs propelled us about as well.

Although the C9 is an ACERT (advanced combustion emissions reduction technology) engine, there's nothing in the driving experience that makes it stand out. It uses a single turbocharger (bigger ACERTed Cats use two), and most emissions-fighting advancements are internal.

Like other Cats, the C9 has no exhaust-gas recirculation, but needs a catalytic converter to strip minute particulates from the exhaust. Unlike Clean Power "bridge" engines, the C9 and all upcoming ACERTed models are fully compliant with October '02/January '04 emissions limits.

Most of my comments as we drove were about the engine, so as we returned to our starting point Crowcroft exclaimed, "Well, what do you think of the truck?" After all, he wants to sell Sterlings whether they've got Cats, Mercedes-Benzes or anyone else's engines.

I assured him that the LT-9500 was pretty nice. Like other Sterlings I've driven, it was roomy and quiet, and combined toughness with smooth automotive styling. Sterling has done a great job of keeping all the attributes of the HN80 Louisville (which Ford Motor Co. sold to Freightliner LLC in 1997) while introducing advances, like the simple but good-riding Freightliner TuffTrack tandem suspension.

I drove several other Sterling LTs, some with Cat C-12s that proved the old drag racer's axiom, "There's no substitute for cubic inches." A bigger engine is simply going to make more power and torque and feel better to the driver.

Now a money note: Caterpillar believes its products are of premium grade, and the company is not shy about charging for them. The C9 will cost somewhat more than competitors—sometimes considerably more—and you have to decide whether its promises of better economy and durability, along with the Cat nameplate, are worth the higher price.