The new Cat CT15 joins the CT11 and CT13 as the third engine option for the versatile Cat CT660 Vocational Truck. The 15-L engine is available with as much as 550 hp and 1,850 lb.-ft. of torque. The dual sequential turbochargers and precisely controlled high-pressure common-rail fuel system enable the CT15 to reach peak torque at 1,200 rpm. The strong pulling power at low engine speeds allows for shifting at lower speeds when accelerating and reduces the need for shifting when powering up steep grades. Interstage cooling between turbochargers increases air density to maintain power as speeds increase. The result is enhanced productivity and less wear and tear on the truck and driver. The CT15 also offers an engine brake rated at more than 600 bhp. The engine brake helps drivers maintain optimum speeds down steep or long grades without frequent use of the service brakes. Proper use optimizes productivity and lowers maintenance costs. Furthermore, like the CT11 and CT13, the CT15 features advanced emissions control technology that helps keep truck weight down and simplifies maintenance.