1976: World premiere of the first Audi five-cylinder gasoline engine

5-cylinder

5-cylinder

Noun

A five-cylinder engine is an internal combustion engine with five cylinders arranged in a line (inline-five) or, more rarely, in other configurations. It combines characteristics of both four- and six-cylinder engines, offering smoother operation and more torque than a four-cylinder while remaining more compact and lighter than a six-cylinder. Five-cylinder engines are known for their distinctive 1-2-4-5-3 firing order, which produces a unique sound and contributes to their enthusiast appeal. They have been used in passenger cars, commercial vehicles, and motorsport applications, with notable development and long-term refinement by manufacturers such as Audi and Volvo.


SYNONYMS + SLANG

  • Inline 5
  • Five Pot (slang)

ARCHIVE TAG

5-cylinder


DETAILED HISTORY

The Audi five-cylinder engine is a family of inline five-cylinder petrol and diesel engines developed by Audi and used in both production vehicles and motorsport since 1976. Closely associated with the brandโ€™s technical identity and โ€œVorsprung durch Technikโ€ philosophy, these engines have powered everything from executive sedans to Group B rally cars and modern RS models. They are noted for their distinctive 1โ€“2โ€“4โ€“5โ€“3 firing order, characteristic sound, and long history of technical evolution from mechanically simple, naturally aspirated units to high-output turbocharged and direct-injection designs.

ORIGINS AND DEVELOPMENT

The introduction of the first Audi 100 in 1968 secured the continued existence of the Audi brand in the post-war era. Its successor, the Audi 100 Type 43 (C2), was conceived to be positioned higher in the market. Audi engineers concluded that the four-cylinder engines then available, derived from the EA 827 family and used widely in vehicles such as the Volkswagen Golf and Passat and the Audi 80 and 100, would not be sufficient for this more upscale positioning.

During the early 1970s, Audi evaluated several engine concepts, including inline five- and six-cylinder designs as well as a V6. The inline six-cylinder was rejected due to packaging concerns and the risk of excessive front-axle weight in a front-wheel-drive chassis. A V6 would have required significant investment in new production tooling and was therefore ruled out on cost grounds.

The inline five-cylinder emerged as the optimal solution. It could be integrated into existing engine production lines and was closely based on the young EA 827 four-cylinder engine family, scaled and adapted to accommodate an additional cylinder. This approach minimized investment while delivering performance and refinement beyond what was possible with contemporary four-cylinder units.

FIRST PRODUCTION APPLICATIONS

The first Audi five-cylinder petrol engine debuted in the Audi 100 Type 43 in 1976, unveiled in Luxembourg. Deliveries of the Audi 100 5E began in March 1977. This engine featured:

  • Displacement: 2,144 cc
  • Configuration: inline five, petrol
  • Fuel system: Bosch K-Jetronic mechanical fuel injection
  • Output: 100 kW (136 PS / 136 hp)

This engine delivered โ€œsix-cylinder power with four-cylinder economy,โ€ and helped position the new Audi 100 higher in the executive segment. Its distinctive sound and smoothness quickly became part of the carโ€™s appeal.

Audi soon expanded the five-cylinder family beyond petrol units. In 1978, the brand introduced its first five-cylinder diesel, a naturally aspirated 2.0-litre engine producing 51 kW (70 PS). This engine gained early publicity through a world endurance run that demonstrated both its efficiency and durability.

1976: first five-cylinder gasoline engine in the automotive industry:

TURBOCHARGING AND PERFORMANCE GROWTH

In September 1979, Audi introduced the first turbocharged five-cylinder petrol engine in the Audi 200 5T. Key data for this engine included:

  • Displacement: 2.1 litres
  • Output: 125 kW (170 PS)
  • Torque: 265 Nm

This was a pioneering application of turbocharging in a high-performance road-going executive car from a German manufacturer. It significantly expanded the performance envelope of the five-cylinder concept and laid the groundwork for even more powerful applications.

The five-cylinder reached a new level of prominence in 1980 with the launch of the original Audi quattro. In this application, the turbocharged, intercooler-equipped five-cylinder engine produced:

  • Output: 147 kW (200 PS)
  • Drivetrain: combined with permanent quattro all-wheel drive

This package became a hallmark of Audiโ€™s engineering identity in both motorsport and series production.

1983: five-cylinder engine triumphant in rallying:

MOTORSPORT AND GROUP B

The five-cylinder engine achieved legendary status in motorsport, particularly in rallying and North American touring car racing.

In the World Rally Championship (WRC), the turbocharged five-cylinder powered the original Audi quattro to major success. Audi won the manufacturersโ€™ title in 1982, and Finnish driver Hannu Mikkola secured the driversโ€™ championship in 1983 using quattro-based machinery.

In 1983, Audi introduced the Sport quattro, a shorter and wider development of the quattro with a newly designed four-valve-per-cylinder, light-alloy five-cylinder engine. Key figures for the road-going Sport quattro were:

  • Output: 225 kW (306 PS)
  • Status: at the time, the most powerful car ever offered by a German manufacturer for road use

The Sport quattro formed the basis for a new Group B rally car in which the four-valve five-cylinder produced approximately 331 kW (450 PS) in competition trim. It debuted in the penultimate round of the 1984 WRC, the Ivory Coast Rally. Over the remainder of the Group B era, Audi deployed both the Sport quattro and the evolved quattro A2. Swedish driver Stig Blomqvist campaigned the 265 kW (360 PS) Audi quattro A2 and won the 1984 driversโ€™ title, with Audi again taking the manufacturersโ€™ championship.

Even after Audiโ€™s withdrawal from WRC Group B in 1986, the five-cylinder engine continued to feature in high-profile competition:

  • Pikes Peak 1987: Walter Rรถhrl won the famous hill climb in the Audi Sport quattro S1 (E2), developing around 440 kW (598 PS).
  • Trans-Am 1988: In the Audi 200 quattro Trans-Am, Audi used a turbocharged 2.1-litre five-cylinder with a two-valve cylinder head, producing about 375 kW (510 PS). American driver Hurley Haywood won the Trans-Am series that year.
  • IMSA GTO 1989: Audiโ€™s IMSA GTO car used a highly developed five-cylinder turbo engine producing around 530 kW (720 PS) from slightly over two litres of displacement, making it one of the most extreme touring car engines of its day.

DIESEL AND TDI DEVELOPMENT

Audi continued to evolve its five-cylinder diesel technology alongside the petrol units. A key milestone was the introduction of the Audi 100 TDI at the 1989 International Motor Show (IAA) in Frankfurt. This model featured:

  • Engine: direct-injection, turbocharged five-cylinder diesel
  • Displacement: 2.5 litres
  • Output: 88 kW (120 PS)
  • Technology: fully electronic engine management

This five-cylinder TDI represented an important step in the development of modern diesel technology, combining direct injection, turbocharging, and sophisticated electronic control.

1994: first five-cylinder RS engine

HIGH-PERFORMANCE ROAD CARS

Throughout the 1980s and early 1990s, Audi broadened the five-cylinder engineโ€™s role in high-performance road cars. Notable models included:

  • Sport quattro (306 PS) โ€“ homologation special for Group B, as noted above
  • Audi 200 quattro 20V โ€“ utilizing a four-valve turbocharged five-cylinder with significant performance gains over earlier engines
  • Audi S2 โ€“ a performance coupรฉ and later Avant using 20-valve turbocharged five-cylinder engines
  • Audi S4 and S6 (C4) โ€“ performance saloons and Avants with turbocharged five-cylinder powertrains
  • Audi Avant RS2 (1994) โ€“ developed in cooperation with Porsche, producing 232 kW (315 PS). This car is often regarded as the founding model of the modern RS and โ€œsuper estateโ€ category.

These models cemented the five-cylinderโ€™s reputation as a compact, high-output engine capable of delivering performance on par with larger six- and eight-cylinder engines.

PHASE-OUT OF THE FIRST GENERATION

With the introduction of the Audi A4 (B5) and Audi A6 (C5) in the mid-1990s, Audi began transitioning from inline five-cylinder engines to more modern V6 units in its mainstream product lines. The first generation of Audi five-cylinder engines remained in production until the late 1990s.

The last production applications included:

  • 2.5 TDI five-cylinder in the Audi A6
  • 2.2-litre 20V turbo petrol five-cylinder in the Audi S6

Both were phased out by approximately 1997, marking the end of continuous five-cylinder engine use in Audiโ€™s larger series models for a period.

2009: 2.5 TFSI with gasoline direct injection, turbocharger and intercooler

COMEBACK IN THE TT RS AND RS MODELS

The Audi five-cylinder made a significant comeback in 2009, thirty years after the debut of the first turbocharged five-cylinder petrol engine. The new generation appeared in the Audi TT RS, developed by quattro GmbH (now Audi Sport):

  • Displacement: 2.5 litres
  • Output: 250 kW (340 PS) in early TT RS and RS 3 applications
  • Technology: turbocharging and direct petrol injection
  • Later development: TT RS plus (2012) with 265 kW (360 PS)

The same 2.5-litre engine architecture powered the RS 3 Sportback and, from 2013, the RS Q3, opening a new segment for compact high-performance SUVs.

In 2016, Audi introduced a substantially revised version of this engine, known internally as the EA855 Evo. Focus areas included lightweight construction, reduced internal friction, and improved power delivery. With a displacement of 2,480 cc, this engine produced:

  • 294 kW (400 PS)
  • 480 Nm of torque (in early EA855 Evo applications)
Audi RS 3 Sportback and Audi RS 3 Sedan, model year 2025

MODERN 2.5 TFSI IN THE AUDI RS 3

Since 2021, the latest generation Audi RS 3 has been equipped with a further-developed 2.5 TFSI five-cylinder, often referred to as EA855 Evo Sport. In this application:

  • Output: 294 kW (400 PS)
  • Torque: 500 Nm, available between 2,250 and 5,600 rpm
  • 0โ€“100 km/h: 3.8 seconds
  • Top speed: electronically limited to 250 km/h, with optional increases to 280 km/h or up to 290 km/h when specified with the RS dynamic package and ceramic brakes

A revised engine control unit enables faster coordination between engine and drivetrain systems, enhancing driving dynamics and responsiveness.

SOUND CHARACTERISTICS

The five-cylinder engine is renowned for its distinctive sound, which plays a major role in its cult status among enthusiasts. The key factors behind this acoustic signature are:

  • Firing order: 1โ€“2โ€“4โ€“5โ€“3
  • Crankshaft rotation interval: 144 degrees between ignition events

This pattern alternates between adjacent and more widely spaced cylinders, creating an irregular but harmonious rhythm not found in four- or six-cylinder engines. The geometry of the exhaust manifold and the differing exhaust gas path lengths between valves and turbocharger further shape the sound.

In modern RS models, Audi uses fully variable exhaust flap control to modulate the sound. Depending on the selected drive mode (e.g., dynamic, RS Performance, RS Torque Rear), the exhaust flaps open earlier and more widely, increasing the emotional intensity. An optional RS sports exhaust system amplifies this effect.

50 years of five-cylinder engines at Audi: unmistakable sound, thrilling performance, and numerous motorsport successes

TECHNOLOGY AND DESIGN FEATURES OF THE 2.5 TFSI

The current 2.5 TFSI embodies Audiโ€™s most advanced five-cylinder technology. Key features include:

  • Turbocharging and direct injection (TFSI) with dual injection: both into the intake manifold and directly into the combustion chamber
  • Audi valvelift system on the exhaust side, providing two-stage variable valve lift for optimized efficiency at low load and improved responsiveness and mid-range power at high load
  • High fuel pressure: up to 250 bar
  • Large turbocharger: generating approximately 1.5 bar relative (2.5 bar absolute) boost pressure

The engine is a long-stroke design (bore 82.5 mm, stroke 92.8 mm), optimized for strong torque delivery across a wide rev range.

Lightweight construction is central to the EA855 Evo:

  • Aluminium crankcase, significantly lighter than prior grey-cast-iron blocks
  • Hollow-bored crankshaft, reducing rotating mass and improving response
  • Magnesium oil pan top section and aluminium belt pulleys
  • Overall engine weight: around 160 kg
  • Overall length: less than 50 cm, enabling transverse installation in compact models

Internal friction and wear are reduced through:

  • Plasma-coated cylinder liners
  • Special oil channels in the piston bases for improved cooling
  • An innovative thermal management system with a switchable coolant pump that shortens warm-up time and reduces friction after cold start
  • demand-controlled aluminium oil pump that adjusts oil pressure based on engine requirements

Together, these measures provide excellent performance with relatively efficient fuel consumption for the power level.

MANUFACTURING AND ASSEMBLY

Modern Audi five-cylinder engines are built at the Gyล‘r plant in Hungary, in a dedicated assembly area known as the Bock assembly. This facility covers more than 1,000 square metres and emphasizes manual assembly by skilled technicians rather than extensive use of robots.

Key aspects of the assembly process include:

  • Construction begins with the aluminium crankcase, onto which the crankshaft, bearing shells, and pistons with connecting rods are installed.
  • A torque and rotation check ensures proper assembly and smooth crankshaft operation.
  • The magnesium upper section and aluminium lower section of the oil pan are fitted, followed by critical components such as injectors, sensors, and the timing chain.
  • The cylinder head is bolted on and fitted with spark plugs, followed by the intake manifold and the large turbocharger.
  • Final steps include installation of the engine wiring harness and dual-mass flywheel, which reduces vibration between engine and seven-speed S tronic transmission.

Each engine undergoes comprehensive mechanical and electronic testing, including:

  • Cold test: with operating fluids, checking for functionality and leaks without full combustion operation
  • Hot test: initial start-up under load to verify performance and durability parameters

Once tests are successfully completed, engines are transported by rail from Gyล‘r to Ingolstadt, where they are installed in vehicles such as the Audi RS 3 in the so-called โ€œmarriageโ€ process that joins powertrain and body.

SIGNIFICANCE AND LEGACY

Since its debut in 1976, the Audi five-cylinder engine has become a core element of the brandโ€™s technical identity. Over five decades, it has:

  • Enabled Audi to move decisively upmarket with the Audi 100 (C2)
  • Powered iconic competition cars in rallying, hill climbs, and touring car racing
  • Served as the heart of numerous performance road cars, from the original quattro and Sport quattro to the RS2 Avant, S and RS models, and modern compact RS vehicles
  • Demonstrated continuous technical evolution, from early K-Jetronic fuel injection to modern TFSI systems with dual injection and advanced valvetrain control

Todayโ€™s 2.5 TFSI continues this tradition with high specific output, compact dimensions, and a distinctive sound that remains closely associated with Audiโ€™s sporting and technological image.


5-CYLINDER ENGINE CODES

EARLY PETROL (C2 / B2 / UR-quattro era)
โ€ข WC โ€“ 2.1 L carbureted I5 (C2 Audi 100)
โ€ข WB โ€“ 2.1 L carbureted I5 (C2 Audi 100)
โ€ข WN โ€“ 2.1 L fuel-injected I5 (100 kW / 136 PS), Audi 100 5E
โ€ข WX โ€“ 2.1 L turbo, early quattro & Audi 200 (147 kW / 200 PS)
โ€ข WR โ€“ 2.1 L turbo, Audi quattro (200 PS)

20V TURBO (late 1980sโ€“1990s performance models)
โ€ข 3B โ€“ 2.2 L 20V turbo (162 kW / 220 PS), original Audi S2
โ€ข 7A โ€“ 2.3 L naturally aspirated 20V (Audi 90 / Coupe 20V)
โ€ข ABY โ€“ 2.2 L 20V turbo (169 kW / 230 PS), updated S2
โ€ข ADU โ€“ 2.2 L 20V turbo (315 PS), Audi RS2 Avant (co-developed with Porsche)
โ€ข AAN โ€“ 2.2 L 20V turbo (169 kW / 230 PS), Audi S4/S6 C4

EARLY DIESEL (C2 / C3 / C4 era)
โ€ข CN โ€“ 2.0 L diesel, naturally aspirated I5 (C2 Audi 100)
โ€ข CY โ€“ 2.0 L diesel, early TDI development
โ€ข D4 โ€“ 2.4 L diesel (C3 Audi 100)
โ€ข AAS โ€“ 2.5 L TDI (C4 Audi 100/A6)
โ€ข ACZ โ€“ 2.5 L naturally aspirated diesel
โ€ข AAT โ€“ 2.5 L TDI (120 PS), Audi 100/A6 C4
โ€ข ABP โ€“ 2.5 L TDI variant
โ€ข AKE โ€“ early V6 TDI successor (included only for timeline context, no longer I5)

MODERN TFSI (EA855 / EA855 EVO / EA855 EVO II)
โ€ข CEPA โ€“ 2.5 TFSI (TT RS Mk1, 250 kW / 340 PS)
โ€ข CEPB โ€“ 2.5 TFSI (slightly updated version of CEPA)
โ€ข DAZA โ€“ 2.5 TFSI (TT RS Mk2, RS 3 8V.2)
โ€ข DAZB โ€“ 2.5 TFSI (updated calibration/export variants)
โ€ข DNWA โ€“ 2.5 TFSI (RS Q3, RS Q3 Sportback)
โ€ข DNWC โ€“ 2.5 TFSI (new RS Q3 variants)
โ€ข DNUE / DNUB / DNFA โ€“ 2.5 TFSI (various market versions of EA855 Evo)
โ€ข DYRA โ€“ 2.5 TFSI (newest RS 3 EA855 Evo Sport, 400 PS / 500 Nm)


NOTES:
โ€ข This list includes the major and historically significant engine codes used broadly across production.
โ€ข Motorsport-only codes (e.g., Group B prototypes) are typically undocumented or non-standard and are therefore excluded.
โ€ข Some codes appear in multiple markets with slight variations; the most widely referenced versions are included here.

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