Bigger Not Always Better Caterpillar C-15 Outperforms Larger Engines

May 1, 2000
Gregg Larson, founder/owner of Larson Trucking Inc (LTI), one of central Utah's largest aggregate and cement haulers, recently discovered the lighter-weight

Gregg Larson, founder/owner of Larson Trucking Inc (LTI), one of central Utah's largest aggregate and cement haulers, recently discovered the lighter-weight Caterpillar C-15 truck engine can pull heavy loads in rough terrain while maintaining optimum performance.

After months of testing the C-15, Larson is convinced that his other trucks, which typically gross more than 129,000 pounds, have been packing around 200 pounds of unnecessary engine weight. In the test truck, this weight has been converted into more payload.

The truck, a 1999 Kenworth W900, hasn't suffered for the loss of engine weight. According to Larson, it has turned into a better on-road performer: "In addition to the increased payload, it uses less fuel, runs quieter, and is even turning in shorter trip times," he said.

For months, the C-15-powered W900 has performed one of LTI's toughest jobs: hauling dry bulk cement 150 miles from a plant in Lemington, Utah, to users in the greater Salt Lake City area. The engine's loaded-on-the-grade performance is outstanding, according to veteran LTI driver Kevin Barney, who has driven LTI tractors with electronic and mechanical engines of all ratings.

"At 129,000 pounds, the C-15-powered W900 has better hill-holding-better effective torque-than other tractors," he said. "It shows up on long, steep grades, such as the 15 miles uphill to Park City, which has several grades of six and seven percent."

The design of the C-15 is based on the 3406 platform, which in 25 years has exceeded two billion miles of highway service. The C-15, however, has enough design changes, component improvements, and upgrades, including a new serpentine engine block and the ADEM 2000 electronics system, to qualify it as a new highway diesel. Reduced weight of the new sculptured block and several of the engine's component parts, and the boost in power and fuel efficiency gained from the ADEM 2000 electronic controls, account for improved operating costs and increased payload advantage.

The 14.6-liter C-15 offers horsepower ratings from 355 to 550, with peak torque power up to 1,850 ft-lb for fuel efficiency and reserve power when needed. As proven by the C-15 tested by fleets like LTI, the engine's peak torque provides superior startability on steep grades with heavy loads.

LTI has 35 highway tractors and 78 trailers moving sand, gravel, and bulk cement within a 200- to 300-mileradius of Salt Lake City. The fleet is projected to double in growth over the next few years. With the kind of growth he is expecting, Larson has no room for wasteful expenses.

"That engine is doing the job. The C-15-powered truck is carrying more payload, moving it faster, and at lower operating cost than heavier engines in the fleet," he said.

"In a typical day, we make $15 more revenue off increased payloads on that truck due to the C-15's lighter weight, and even more than that in shorter runs," Larson said.

Fuel consumption also is lower. Larson says he sees a quarter-mile-per-gallon improvement in fuel mileage, and once the engine is broken in, he expects that to improve to a half-mile per gallon. Better engine performance on long hauls is saving 10 minutes per trip, which amounts to a cumulative four hours less operating time every month.

"Reductions in both operating time and fuel cost, and the increase in payload, are significant. Multiply that by 35 trucks and you are talking about the potential of some real money," Larson said.