Lancia Delta S4 "Stradale"

Overview
Manufacturer	Lancia
Production	1985–1986
Body and chassis
Body style	2-door coupé
Layout	Mid-engine, four-wheel-drive
Powertrain
Engine	1.8 L I4 (supercharged and turbocharged petrol)
Transmission	5-speed manual
Dimensions
Length	4,005 mm (157.7 in)
Kerb weight	1,200 kg (2,646 lb)
Chronology
Predecessor	Lancia Rally 037 "Stradale"

The Lancia Delta S4 is a Group B rally car from the Italian car company Lancia. The Delta S4 competed in the World Rally Championship in 1985 and 1986, until Group B class was disbanded and the cars were eventually banned from competition completely by European sanctioning body FIA. The car replaced, and was an evolution of, the Lancia 037. The S4 took full advantage of the Group B regulations, and featured a midship-mounted engine and all-wheel drive for superior traction on loose surfaces.

The car's 1,759.3 cc four-cylinder engine combined supercharging and turbocharging to reduce turbo lag at low engine speeds. The car produced a maximum output of 480 horsepower (350 kW), but some sources even claim that the Delta S4 was capable of producing 500 horsepower (417 kW). In 1985, Lancia engineers tested an S4 engine under extreme conditions, reaching 5 bars boost, developing around 1000 horsepower. An engine capacity multiple of 1.4 was applied to forced induction engines by the FIA and the choice of 1,759 cc put the S4 in the under 2,500 cc class, which allowed for a minimum weight of 890 kg (1,962 lb). The combined super/turbocharger system (often referred to as twincharging) was a development of the 037 engine that produced 350 hp (261 kW) with a supercharger only.

Like Peugeot's earlier 205 T16, the mid-engine Lancia Delta S4 was a Delta in name and body styling only (for marketing purposes), and shared virtually nothing in terms of construction with the production front-engine Delta. The chassis was a tubular space frame construction much like the 037. It featured long travel double wishbone suspension front and rear, with a single large coil over at the front and separate spring and twin shock absorber at the rear. The bodywork was made of a carbon fibre composite with front and rear bodywork fully detachable for fast replacement due to accident damage, allowing ease of access during on-event servicing. The bodywork featured several aerodynamic aids including bonnet opening behind the front-mounted water radiator with Gurney flap, front splitter and winglets moulded into the front bumper panel, flexible front skirt, and rear deck lid wing that featured both a full aerofoil wind section twinned with a deflection spoiler. The door construction style was brought from the 037 with a hollow shell all-Kevlar construction that had no inner door skin, no door handle or window winder. The door was opened with a small loop and the windows were fixed perspex with small sliding panels to allow some ventilation and passing of time cards and suchlike.

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Wikipedia