The Lancia Delta first appeared in 1979, a five-door hatchback designed by Giorgetto Giugiaro that was voted the 1980 European Car of the Year. Its competition story began with the turbocharged front-wheel-drive Delta HF in 1983, but the critical step came in 1986 when Lancia introduced the Delta HF 4WD — a turbocharged 2.0-litre, four-wheel-drive variant unveiled at the April 1986 Turin Motor Show.
The four-wheel-drive system used on all HF models was derived from the drivetrain developed for the 1985 Lancia Delta S4 Group B rally car, adapted from a mid-engine layout to a transverse front-engine configuration. The system used three differentials: a central epicyclic unit controlled by a Ferguson viscous coupling, an open front differential, and a Torsen rear differential that could lock up to 70% automatically based on available grip.
The HF 4WD's 1,995 cc twin-cam eight-valve engine, derived from the Lancia Thema saloon, produced 165 PS at 5,250 rpm. In its first works outing at the 1987 Monte Carlo Rally, it took the top two places. It went on to win 9 of 13 championship rounds that season and claimed the 1987 World Rally Championship for Manufacturers. Juha Kankkunen also took the Drivers' title that year.
In September 1987 the HF 4WD gave way to the Delta HF Integrale, incorporating lessons from the works rally program. The eight-valve 2.0-litre engine now produced 185 PS at 5,300 rpm with 31 kgf·m of torque at 3,500 rpm, and the car gained visually wider wheel arches to accommodate broader tyres on 15-inch wheels.
The 16-valve Delta HF Integrale followed in March 1989, introduced at that year's Geneva Motor Show. Its turbocharged two-litre 16-valve engine produced 200 PS at 5,500 rpm, enabling a 0–100 km/h time of 5.7 seconds and a top speed of 220 km/h. The torque split was revised to 47% front and 53% rear, improving balance. It made its winning debut at the 1989 San Remo Rally.
The Evoluzione, announced at the September 1991 Frankfurt Motor Show, raised output to 210 PS at 5,750 rpm through a new 60 mm single-outlet exhaust system. It featured wider front and rear tracks, extended wheel arch flares made as single pressings rather than welded additions, new Speedline Montecarlo alloy wheels matching the rally car specification, a manually adjustable rear roof spoiler, and Brembo two-piston front brake calipers. The final Evoluzione II, presented in June 1993, developed 215 PS and added a three-way catalytic converter with lambda probe, while standard equipment expanded to include ABS, fog lamps, and Recaro seats.
Across its works career, the Delta in its HF 4WD, Integrale, and Integrale 16v forms accumulated 46 WRC victories. It won six consecutive Constructors' Championships: 1987 through 1992. Drivers' titles went to Juha Kankkunen (1987 and 1991) and Miki Biasion (1988 and 1989).
Lancia officially retired from factory rallying after the 1991 season, but factory-developed Evoluzione cars were run by the Martini Racing-backed Jolly Club for 1992. This arrangement secured Lancia's sixth and final consecutive Constructors' title. The 1993 Evoluzione II was not developed into a works rally car; those were the final homologation models.
A total of 44,296 Integrale road cars were produced across all variants.
The Lancia Delta Integrale's six consecutive Constructors' Championships remain the most dominant sustained record in World Rally Championship history. The car proved that a sophisticated four-wheel-drive system, combined with a turbocharged engine and a well-developed road-car platform, could dominate an entire era of the sport. Road-going Integrales, particularly the Evoluzione variants, are now considered among the greatest performance cars of the late 1980s and early 1990s, combining everyday usability with genuine motorsport heritage. The car's dominance effectively ended Lancia's works rally program on the highest possible note, and it is widely regarded as the definitive Group A rally car.