PSA XUD engine

The XUD was available with either SOHC 8-valve or 12-valve heads. It was mainly applied transversally in front wheel drive vehicles, tilted by 30°. However, some applications in non-PSA vehicles had the engine installed longitudinally, with rear-wheel drive. The XUD is built in Citroën's plant in Trémery, near Metz.[1]

Displacement ranges between 1.8 and 2.1 L (1,769 and 2,138 cc), and all XU diesel engines have a stroke of either 88 or 92 mm (3.46 or 3.62 in). The former was shared with the XU9. Bore sizes range from 80 to 86 mm (3.15 to 3.39 in), some of which are shared with other XU engines.

Upon its release the engine was noted as one of the best diesel engines (for cars and light vans) in the world with its high power output and refinement it made all other diesel engines seem agricultural.[1] It was also particularly light, with a ready-to-run XUD9 weighing 157 kg (346 lb), 15% less than a comparable diesel of the previous generation.[1]

The XUD7 has a displacement of 1.8 L (1,769 cc), with a bore and a stroke of 80 mm × 88 mm (3.15 in × 3.46 in). Output is 60 PS (44 kW; 59 hp) for the naturally aspirated version or 78 PS (57 kW; 77 hp) for the turbocharged model. An intercooled turbocharged version was introduced later, with 90 PS (66 kW; 89 hp) on tap. All are Diesel engines.

XUD9A engine in FSO Polonez Caro

The XUD9 has a displacement of 1.9 L (1,905 cc), with a bore and a stroke of 83 mm × 88 mm (3.27 in × 3.46 in). Both turbocharged and naturally aspirated versions were produced. Most turbocharged versions feature an intercooler, although a limited number of installations in the Citroën Xantia featured a Turbocharger without intercooler. Both engines also featured either a Bosch or a Lucas mechanical fuel pump and injectors. The engine version with the Bosch pump is known to have been run with vegetable oil. The original XUD9 engine is known as the "square port" engine, as its cylinder head has square exhaust ports. Later (and noticeably improved) XUD9A engines have oval ports.

The XUD11 was available in two displacements:

• 2.1 L (2,138 cc) — XUD11 A naturally aspirated
• 2.1 L (2,088 cc) — XUD11 ATE/BTE turbocharged

Both were 12-valve SOHC engines with a 92 mm (3.62 in) stroke. The naturally aspirated XUD11 A was bored to 86 mm (3.39 in) for a total displacement of 2.1 L (2,138 cc), while the turbocharged ATE/BTE versions were reduced in bore to 85 mm (3.35 in) for a total of 2.1 L (2,088 cc).

The engine has been installed into the following vehicles:-

• Guide des moteurs Peugeot Citroën (in French)