The PSA XU is a family of

internal combustion engine An internal combustion engine (ICE or IC engine) is a heat engine in which the combustion of a fuel occurs with an oxidizer (usually air) in a combustion chamber that is an integral part of the working fluid flow circuit. In an internal comb ...

s used in

Citroën Citroën ()The double-dot diacritic over the 'e' is a diaeresis () indicating the two vowels are sounded separately, and not as a diphthong. is a French automobile brand. The "Automobiles Citroën" manufacturing company was founded on 4 June 19 ...

and

Peugeot Peugeot (, , ) is a French automobile brand owned by Stellantis. The family business that preceded the current Peugeot companies was established in 1810, making it the oldest car company in the world. On 20 November 1858, Émile Peugeot applie ...

automobile A car, or an automobile, is a motor vehicle with wheels. Most definitions of cars state that they run primarily on roads, Car seat, seat one to eight people, have four wheels, and mainly transport private transport#Personal transport, peopl ...

s. It became the dominant mid-size engine in Peugeot and Citroën products through the 1980s and 1990s. The XU design was introduced in 1981 with the Peugeot 305. It was a

SOHC An overhead camshaft (OHC) engine is a piston engine in which the camshaft is located in the cylinder head above the combustion chamber. This contrasts with earlier overhead valve engines (OHV), where the camshaft is located below the combus ...

DOHC An overhead camshaft (OHC) engine is a piston engine in which the camshaft is located in the cylinder head above the combustion chamber. This contrasts with earlier overhead valve engines (OHV), where the camshaft is located below the combus ...

straight-4 A straight-four engine (also referred to as an inline-four engine) is a four-cylinder piston engine where cylinders are arranged in a line along a common crankshaft. The majority of automotive four-cylinder engines use a straight-four layout ( ...

design with two or four valves per cylinder, using

petrol Gasoline (North American English) or petrol ( Commonwealth English) is a petrochemical product characterized as a transparent, yellowish, and flammable liquid normally used as a fuel for spark-ignited internal combustion engines. When formul ...

as fuel. It was applied transversely in

front wheel drive Front-wheel drive (FWD) is a form of internal combustion engine, engine and transmission (mechanics), transmission layout used in motor vehicles, in which the engine drives the front wheels only. Most modern front-wheel-drive vehicles feature ...

vehicles only, tilted by 30°. Displacement ranged between , and all production XU gasoline engines had a bore of . The engine uses an aluminium cylinder head in all models. All models' blocks are made, except XU10, in cast aluminium alloy with removable cast iron wet cylinder liners. XU10 blocks are made in cast iron, with bores machined directly in the block, without removable cylinder liners. Its first Citroën application was on the Citroën BX in 1982, where it appeared in format. The XU was replaced by the more modern EW/DW family.

XU5

The XU5 had a displacement of , with a bore and a

stroke Stroke is a medical condition in which poor cerebral circulation, blood flow to a part of the brain causes cell death. There are two main types of stroke: brain ischemia, ischemic, due to lack of blood flow, and intracranial hemorrhage, hemor ...

of . All XU5 engines were SOHC 2-valve per cylinder designs. They used either a single or double-barrel

carburetor A carburetor (also spelled carburettor or carburetter) is a device used by a gasoline internal combustion engine to control and mix air and fuel entering the engine. The primary method of adding fuel to the intake air is through the Ventu ...

, or

fuel injection Fuel injection is the introduction of fuel in an internal combustion engine, most commonly automotive engines, by the means of a fuel injector. This article focuses on fuel injection in reciprocating piston and Wankel rotary engines. All c ...

, depending on model. Output ranges from .

XU7

The XU7 had a displacement of , with a bore and a

of . All XU7 engines used fuel injection, with a 16-valve DOHC version, the XU7 JP4, also produced. Output ranged from .

XU8

The XU8 had a displacement of , with a bore and a stroke of . The only engine in this family is the 16-valve DOHC turbocharged XU8 T which was fitted to the Peugeot 205 Turbo 16.

XU9

The XU9 was the predecessor to the XU10 and had an aluminum block with wet iron liners. It had a displacement of , with a bore and a stroke of . Many versions were produced, from a double-barrel carburetted 8-valve to a 16-valve DOHC fuel injected model. Output ranged from .

XU10

The XU10 has a cast iron block with a displacement of , with a bore and stroke of , making it a square engine. Many versions were produced, from a double-barrel carburetted 8-valve to a 16-valve DOHC, fuel injected, turbocharged model. Output ranged from .

Motorsport

The XU engine was used in motorsport for over 3 decades.

Sources

Guide des moteurs Peugeot Citroën
(in French) {{PSA Peugeot Citroën XU Straight-four engines Gasoline engines by model

XU5

XU7

XU8

XU9

XU10

Motorsport

See also

Sources