Written By, Mike McGlothlin
CAT C11
History
The CAT C11 engine was part of a busy heavy-duty engine lineup offered by Caterpillar back around the turn of the century. A 677 cubic inch (11.1L), all-iron inline-six with a 5.12-inch bore and a 5.51-inch stroke, the C11 entered production in December of 2003. It was designed to meet tighter NOx standards that had been mandated by the U.S. EPA, and the engine debuted with CAT’s Advanced Combustion Emissions Reduction Technology (ACERT) onboard. Among other things, the C11 received a new style cylinder head, with variable valve actuation (VVA) capability, and it was also equipped with a pair of turbochargers that worked in series (better known as a compound turbo arrangement). These design elements defined many of the core CAT C11 specs used across applications.
Common Applications
Like most heavy-duty CAT engines, the C11 found a home both on and off road. In on-highway applications, such as medium duty trucks, the C11 enjoys an operating range of 1,200 rpm to 2,100 rpm, and produces anywhere from 305 hp to 385 hp, establishing the typical cat c11 horsepower range. Torque output spans from 1,050 lb-ft to 1,450 lb-ft, all available at a low 1,200 rpm. Caterpillar’s C11 is commonly found in agriculture (farm tractors, combine harvesters, sprayers) and construction equipment (loaders, cranes, rollers, crushers, etc.), but it’s also used in a variety of industrial, mining, oil field, and forestry applications.
Production Run
Shipment numbers were never staggering for the on-highway version of the CAT C11, as the C13 produced at the same time enjoyed higher demand thanks to its longer stroke and higher power rating(s). In short, CAT’s C11 was never a bad engine—it was just the power plant no one really wanted. The C11 was only on the assembly line from 2003 to 2006. However, there is no denying that the C11 played a small role in Cat’s securing 35-percent control of the heavy-duty on-highway diesel engine market by the middle of 2004.
Why It Was Short-lived
Due to the higher take rate on the C13 (the C11 and C13 were often both offered for the same application), Caterpillar likely never sold enough C11’s for vocational truck use to justify the cost of continuing to produce it. The C11 was discontinued from Caterpillar’s on-highway lineup in 2006 (2007 model year). That said, they often go 600,000 to 700,000 miles before an overhaul is required but can also last 900,000 miles or more under the right circumstances. As an early ACERT engine, most C11’s are also void of a DPF, which means no Cat Regeneration System (CRS) and all of the problems that came with it.
Sources:
Big Bear Engine Company
https://www.4btengines.com/cat-c11-engine/
Release of the C11
35-percent of Heavy Duty Segment
https://www.fleetowner.com/news/article/21673807/caterpillar-releases-2007-engine-lineup
