LANCIA DELTA S4

Lancia soon realized that, in spite of winning 1983 World Championship with the 037 Rally, four-wheel drive was key to success in the future, so by the end of that year they were already working on the first chassis of the initially labeled as the project 038, designed by Sergio Limone.

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H.Toivonen/S.Cresto, Lancia Delta S4, 1986 Monte Carlo Rally, 1st

The car was carefully optimized in the wind tunnels of the Fiat Research Centre located in Orbassano, reaching a reduction of 12% in Cx coefficient versus Lancia Rally 037, to compensate the increase in frontal area.

Different aerodynamic devices were tested in the car during the development tests. In late 1984 tests, the car was fitted with a blade at the rear part of the roof, similar to that previously used in Lancia Stratos and Fiat 131 Abarth, plus a wing located down in the rear windshield.

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The car was tested then in 1985 Costa Smeralda and Mille Pistes Rallies, where it participated aside of the competition, using a big wing located in the rear part of the roof.

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PROTOTIPO - RALLY MILLE PISTE 1985

M.Alen/I.Kivimaki, Lancia Delta S4, 1985 Rally of Mille Pistes

Rear wing size was reduced and relocated closer to the roof for the car debut, while a large front spoiler was included to reduce airflow down the car, thus helping to generate pressure downwards in the car front at high speeds. The first real rally came in Portugal, where Alen drove the Lancia Delta S4 to the lead of Rally Algarve until he had to retire.

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M.Alen/I.Kivimakki, Lancia Delta S4, 1985 Rally of Algarve, ret.

The plan was to align new car in 1985 Catalunya Rally, but it had to be delayed as homologation did not arrive on time. Instead, Lancia took the opportunity to present the car to the press and to carry out additional tests at the Circuit de Can Padró (Barcelona). Finally, FIA homologated the car (see Lancia Delta S4 Homologation Form here), and the new car could be finally enrolled into the 1985 RAC Rally, with the purpose of testing the car for the next season.

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H. Toivonen/Wilson, Lancia Delta S4, 1985 RAC Rally, 1st

What should have been a test rally ended with an astonishing 1-2 for Lancia, thanks to Henri Toivonen and Markku Alen. The small roof-mounted single wing was only used in this race with this configuration.

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M.Alen/I.Kivimaki, Lancia Delta S4, 1985 RAC Rally, 2ond

Lancia success continued in early 1986, as Toivonen won Monte Carlo Rally and Alen was second in Sweden.

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H. Toivonen/Wilson, Lancia Delta S4, 1986 Montecarlo Rally, 1st

In Sweden 1986, side panels were added, allowing to locate the wing in three different positions (front low (A), rear high (B), which is the one shown in picture below, as can be inferred from the pairs of holes in the side panel, and rear low (which we will name C).

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It will even allow the team to mount a second wing, depending on the rally requirements, as shown in the drawing below, extracted from car’s FIA Homologation form.

delta s4 homologation data

The configuration in the rear low position was rarely used. The picture below shows an example from 1986 Rally of New Zealand.

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M.Biasion/T.Siviero, Lancia Delta S4, 1986 Rally of New Zealand, 3rd

According to Sergio Limone: Aerodynamics were not a strong point of the S4. We made the choice to concentrate on getting a good handling balance in the car and didn’t do much aerodynamic development. But the roof-mounted double wing was quite complex. If you watch the road dust in film footage of the S4 it goes up to four meters into the air, so we were moving a lot of air with medium effort. (Source: Motor Sports Archive, February 2006).

The double wing was rarely used. There are only a few images available of this configuration in competition, in the awful Tour de Corse of 1986. Both wings were located in the rear positions (B and C).

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H. Toivonen/S.Cresto, Lancia Delta S4, 1986 Tour de Corse, retired.

The presence of a rear blade behind the wings seems to be located to accelerate the air flowing between the two wings.

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H. Toivonen/S.Cresto, Lancia Delta S4, 1986 Tour de Corse, retired.

1986 Lancia season changed dramatically when Henri Toivonen and Sergio Cresto died in an accident during the Tour de Corse, one year later than Attilio Bettega dead in the same rally, what moved FIA to ban group B cars for the next season.

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M.Alen/I.Kivimaki, Lancia Delta S4, 1986 Tour de Corse, retired.

In spite of victories in Argentina (Miki Biasion), Sanremo and Olympus (Alen) Rally, world titles escaped to Lancia and Alen at the end of the season.  Peugeot obtained his second manufacturer’s title in a row and Juha Kankkunen obtained his first driver’s title.

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M.Alen/I.Kivimaki, Lancia Delta S4, 1986 Olympus Rally, 1st

Markku Alen gave the car his last victory in the last race of 1986 season, the Olympus Rally. This was last time where group B cars were allowed to participate in the World Championship. Other cars developed by end of 1985 (MG Metro 6R4, Ford RS 200 and Citroen BX 4TC) were aligned in some of the 1986 rallies, and they also included original aerodynamic solutions that are worth to review.

One of the most special was the MG Metro 6R4, as a unique example of F1 technology incorporated into rallying.

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