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 combus ...

s used in Citroën and

Peugeot Peugeot (, , ) is a French brand of automobiles owned by Stellantis. The family business that preceded the current Peugeot companies was founded in 1810, with a steel foundry that soon started making hand tools and kitchen equipment, and the ...

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

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 The Peugeot 305 is a medium-sized car produced by the French automaker Peugeot from 1977 to 1989. It was offered as a four-door saloon, five-door estate, and as a three-door van body derivative. History Origins During the mid 1970s, the motoring ...

. It was a SOHC or

DOHC An overhead camshaft (OHC) engine is a piston engine where 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 combustion c ...

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

design with two or four valves per cylinder, using

petrol Gasoline (; ) or petrol (; ) (see ) is a transparent, petroleum-derived flammable liquid that is used primarily as a fuel in most spark-ignited internal combustion engines (also known as petrol engines). It consists mostly of organic c ...

as fuel. It was applied transversely in

front wheel drive Front-wheel drive (FWD) is a form of engine and transmission layout used in motor vehicles, where the engine drives the front wheels only. Most modern front-wheel drive vehicles feature a transverse engine, rather than the conventional longitu ...

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 liner In a reciprocating engine, the cylinder is the space in which a piston travels. The inner surface of the cylinder is formed from either a thin metallic liner (also called "sleeve") or a surface coating applied to the engine block. A piston is se ...

s. Its first Citroën application was on the

Citroën BX The Citroën BX is a large family car which was produced by the French manufacturer Citroën from 1982 to 1994. In total, 2,315,739 BXs were built during its 12-year history. The hatchback was discontinued in 1993 with the arrival of the Xantia, ...

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 A stroke is a medical condition in which poor blood flow to the brain causes cell death. There are two main types of stroke: ischemic, due to lack of blood flow, and hemorrhagic, due to bleeding. Both cause parts of the brain to stop functionin ...

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

carburetor A carburetor (also spelled carburettor) is a device used by an 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 venturi tube in the main meteri ...

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

, depending on model. Output ranged 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 The Peugeot 205 is a supermini (B-segment) car produced by the French manufacturer Peugeot from 1983 to 1999. It was declared "car of the decade" by ''CAR Magazine'' in 1990. It also won ''What Car?s Car of the Year for 1984. The 205 was introd ...

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 had a cast iron block with a displacement of , with a bore and stroke of , meaning it was 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