The first number indicates the number of cylinders per engine, the "V" indicates a V-type cylinder arrangement, and the last set of numbers indicates the series of the engine. Suffixes are commonplace with Detroit Diesel model designations: "T" means the engine is equipped with turbochargers, "I" for intercoolers, and "B" for by-pass Roots-type blowers. For example, the 20V149 TIB has 20 cylinders in a V-type configuration, is a Series 149 engine, and is turbocharged, intercooled, and has by-pass blowers. Specific models The 12V and 16V configurations have two blocks, two crankshafts bolted together, two blowers, and four turbos. The 16V149 has dual exhaust outlets with eight bolt flanges. The 20V configuration was mainly designed for haul trucks. Detroit could push the envelope of the 16V (in the marine version it could produce @ 2100 RPM) but it would require special parts. They wanted with standard production parts, so the 20V149 was born. It has 3 engine blocks, 3 crankshafts bolted together. The unique set up of the 20V has a 6V block on either end of a special 8V block with 6 turbos, 3 blowers and intercoolers. End of production Production of Series 149 engines was phased out by mid-1999 and MTU Friedrichshafen's 4000 series of four-stroke diesel engines was proposed as helping to fill the void left by the cessation of the 149 Series production. Detroit Diesel and MTU jointly developed the 2000 and 4000 series, with Detroit Diesel leading development of the 2000 and MTU leading the 4000, each of which are named for the per-cylinder displacement in cm3. Like the Series 149, the 4000 comes in 8V-, 12V-, 16V-, and 20V- configurations. Remanufactured Series 149 long blocks are available for off-highway use. References External links 149 Two-stroke diesel engines