Lancia Delta HF 4WD (1986)
Lancia Delta HF 4WD
The Lancia Delta was a successful car sold by Lancia from 1979 to 1994 and was designed by Giorgetto Giugiaro. In Sweden, it was sold by Saab Automobile as the Saab 600. Saab also helped with the logistics and as a result, the Delta was better suited for colder climates and less prone to rust than other Lancias. Its key competitors were the Volkswagen Golf, Vauxhall Astra/Opel Kadett and Ford Escort. For a few years after its launch, the Delta was one of the most contemporarily styled cars of its class in Europe.
While the majority of Delta models were ordinary compact family cars, the most famous model was the Delta HF Integrale, a 4WD hatchback with a powerful turbo-charged engine. A tweaked version of the HF dominated the World Rally Championship, scoring 46 WRC victories overall and winning the Constructors Championship six times in a row from 1987 to 1992, a record.
The Lancia Delta S4, while sharing the same name and appearance, was a "Group B" race car designed specifically for rallying, and entirely different from the commercial Delta in terms of construction and performance.
The Delta was voted Car of the Year in 1980.
In 1985 the rallying world suffered a tremendous blow in terms of development as FISA decided to scrap plans for a proposed Group S as well as cancelling Group B. It was ruled that Group B cars were too fast and, as a consequence, too dangerous. It turns out that Lancia was one of the more far sighted manufacturers since it already had the HF 4X4 production car in the pipeline, using experience gained from the development of the S4 rally car.
Superseding the Delta HF turbo as the flagship of the Delta range -(S4 excepted)-the HF 4WD had a lot to live up to. 'The HF Turbo i.e.' was no slouch and it's handling was praiseworthy for a front-wheel drive car.
The Delta range was first introduced to the UK in 1980 and remained virtually unchanged until 1986, when small changes were made to the body shape and the engines updated; plus, of course, there was the addition of the four-wheel drive model. One of the features of the HF 4WD is the under-statement of the body treatment.
There is very little to distinguish it from the 'Turbo i.e.' apart from the four-headlight system, fog lamps mounted in the front spoiler, discreet 4WD badging on the rear hatch, the small side skirts and two raised air intakes on the bonnet. It is therefore virtually indistinguishable from the 1600cc HF Turbo i.e.
With 165bhp on tap the best way of transfering it to the road is via four, rather than two-wheel drive. In the Delta HF 4X4, Lancia was not content to go for a simple system but rather opted for one with an in-built torque-splitting action to ensure that the available power was going to the wheels with the most traction at any given time, thus ensuring the most efficient use of the available power and torque.
Three differentials are at the heart of the system. Drive to the front wheels is linked through a free-floating differential; drive to the rear wheels is transmitted via a 56/44 front/rear torque-splitting Ferguson viscous-coupling-controlled epicyclic central differential. The real innovation as far as production cars are concerned however, lies between the rear wheels.
The Torsen (torque sensing) rear differential is similar to that found on McLaren Formula 1 cars. The result of combining these differentials in this configuration is an automatic-thinking four-wheel-drive system which requires no manual input from the driver, yet ensures maximum potential traction at any given time.
The Torsen differential is a true 'intelligent' differential in the way it distributes torque. It divides the torque between the two wheels according to the grip available and it does it without ever locking fully; maximum lockup is 70 per cent.
Standard differentials are either free-floating or self-locking. Free-floating systems are good at differentiating between wheel speeds on bends, but always supply the same amount of torque to both wheels. In this situation, however, there is a risk that the wheel with the lighter load (on an incline, for example) or less grip, will lose traction. To counteract this possibility, totally self-locking differentials ensure that both wheels rotate at the same speed but in doing this, prevent free differentiation in cornering, to the detriment of handling and stability.
The basic suspension layout of the 4WD remains the same as in the rest of the 2 wheel drive Delta range: Mac Pherson strut-type independent suspension with dual-rate dampers and helicoidal springs, with the struts and springs set slightly off-centre.
There are a few more subtle changes, though, with the suspension mounting points to the body shell, now better insulated by incorporating flexible rubber links to provide improved isolation. Progressive rebound bumpers have also been adopted, while the damper rates, front and rear toe-in and the relative angle between springs and dampers have all been altered. The steering retains the rack and pinion mechanism of the rest of the Delta range, but in this application it is power-assisted. Steering effort has been reduced further by fitting thrust bearings of the ball, rather than roller type. Additional steering sensitivity has also been obtained by adjusting the angle of incidence of the steering rack.
In 1993 the Delta's successor, the so-called Delta Nuova — based on the Fiat Tipo platform, was introduced. This model was not sold in the United Kingdom, not only because it was not available in right hand drive (despite the fact that the Delta Integrale had sold well even with only left hand drive versions available), but also because the brand had become increasingly unpopular in that country due to rust problems with older Lancias. Lancia finally abandoned the UK market and other right hand drive markets in 1994.
The Delta Nuova was targeted for more comfort-oriented customers. Since Fiat acquired Alfa Romeo in 1990, there was no need for Fiat to build sports cars under two different brands. The Delta Nuova could offer up to 187 DIN-bhp (139 kW) but without four wheel drive.
Even today, one can find old HFs rallying around Italy, with modified versions that rate from 300 to 500 hp (224 to 373 kW).
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