Lancia’s Vicious Twin-Charged Group B Rally Hatch
There was a time when Lancia didn’t just participate in motorsport, they defined what the sport was. Long before the brand was reduced to selling badge-engineered urban commuters, the brand was at the forefront of automotive innovation. They gave us the V4 engine, the first production monocoque, and a trail of motorsport legends ranging from the Aurelia with the first production V6 to the razor-sharp Stratos. By the early 1980s, Lancia was a household name on the international rally stage. But a new set of regulations allowed Lancia to unleash a car that was so wild, they had to build a road version to be eligible for racing.
Group B Needed Road Cars To Exist
Group B was a new rally racing category introduced in 1982 by FISA (Fédération Internationale du Sport Automobile) with a new set of rules that was designed to attract top-tier auto manufacturers. Participation was surprisingly straightforward: build 200 road-legal examples of a race car to gain homologation, and you could compete. Once those 200 base cars were validated, manufacturers could build a further 20 “Evolution” models each year to keep pushing performance boundaries.
The new regulations imposed almost no restrictions on boost pressure, body materials, or horsepower. You could make your car as light, powerful, and fast as possible, as long as it shared similar components with the road car. The street legal homologation specials were known as Stradale in Italy. These were not fancy body-kit versions of cars you would find in a showroom. They were raw, barely disguised race cars sold to the public purely to satisfy the final requirement of the racing rules.
Group B Cars Were Weapons
Group B rapidly transformed from a motorsport championship into an arms race. Early cars like the mid-engined Lancia 037 and the rear-engine Renault 5 Turbo proved that the mid-engine weight distribution was crucial for agility. These machines were so extreme that safety seemed to be an afterthought. The space-frame chassis were skinned in ultra-thin Kevlar, fiberglass, or carbon composite with powerful fire-spitting engines sitting right behind the driver. With zero driver aids, minimal crash protection, and massive turbo lag, Group B cars demanded absolute commitment and courage to drive. They were unruly, light, and violently fast.
Four-Wheel Drive Changed The Game Forever
In 1980, Audi dropped a bombshell on the rally world with the Quattro. Until that point, all-wheel drive was considered too heavy and complex for performance applications. Audi proved the industry wrong, using permanent four-wheel drive tech to transfer massive power directly to dirt, snow, and gravel. This was a massive advantage for Audi since their heavy, front-engined layout gave it more understeer, yet its acceleration out of corners was unmatched. Suddenly, traditional rear-wheel-drive rally cars were left spinning their wheels in the dust. The competitive landscape had shifted permanently in Audi’s favor.
Lancia’s 037 Had To Die First
Lancia didn’t go down without a fight. Their gorgeous, mid-engine, rear-wheel-drive 037 managed to snatch the 1983 World Rally Championship for Manufacturers. This was the last rear-wheel-drive car ever to do so. It was a triumph for the team with superior engineering balance, clever team tactics, and sheer driver willpower to overcome the brute force of Audi’s all-wheel drive.
However, Lancia’s management knew the 037 was living on borrowed time. On loose surfaces, no amount of chassis tuning could overcome a two-wheel-drive traction deficit. To remain competitive, Lancia had to retire the 037 and start from a clean sheet of paper. They needed an all-wheel drive challenger, but they were determined to do it the Lancia way. The next car would still be mid-engined, but would have all-wheel drive, plenty of boost, and a body shape totally different from the retired 037.
The Delta S4 Stradale Was A Crazy Group B Car
Unveiled late in 1985, the Lancia Delta S4 Stradale shared almost nothing with the standard, front-wheel-drive Delta hatchback sitting in local Italian dealerships, save for its badges, windshield angle, and grille outline. Underneath the skin was a chrome-molybdenum tubular space-frame chassis. The entire rear clip hinged upward to reveal a mid-mounted engine positioned longitudinally behind the front seats.
Its all-wheel-drive system had three differentials, including a central Ferguson viscous coupling that split torque roughly 30% to the front and 70% to the rear. These were all parts shared with the rally car, making it a thoroughbred race car for the street with a detuned engine that made it barely legal enough to wear license plates. The engine was also another crazy engineering feat by Lancia.
Lancia Put Two Boosters On One Tiny Engine
The engine was called the Tipo 233 ATR 18S: A 1.8-liter 16-valve inline-four. Most rally cars used turbochargers in this era for more power, but they suffered from massive turbo lag, and Lancia had a solution for this. The turbochargers would provide massive top-end power, while a supercharger would deliver instant throttle response off the line but tap out at higher engine speeds. This twin charging system was genius.
At low RPMs, a belt-driven Roots-type supercharger forced air directly into the engine, eliminating lag. As engine revs climbed and exhaust pressure grew, the large turbocharger would spool up. A series of bypass valves then disengaged the supercharger, letting the massive turbo feed the engine at high-RPM.
In the road-going Stradale, the engine produced a detuned 250 hp and the car weighed just over 2,600 lbs (1,200 kg). In rally spec, the S4 made roughly 480 hp. By 1986, with boost levels turned up, race engines were making around 550 hp in a car weighing under 2,200 lbs (970 kg). Lancia engineers famously tested the block up to 1,000 hp on engine dynos under extreme boost pressures but had to dial it back for competition use and longevity.
The Delta S4 Was Instantly Victorious
The Delta S4 made its World Rally Championship debut at the final round of the 1985 season, the Lombard RAC Rally in Great Britain. Driven by Finnish driver Henri Toivonen with co-driver Neil Wilson, the car stormed to an immediate 1–2 finish alongside teammate Markku Alén. This suddenly proved that Lancia’s recipe worked.
It was faster and more agile than the competition, carrying momentum through corners with explosive power. The S4 looked unstoppable heading into the 1986 season. But Group B was becoming a very dangerous sport, and as power soared past 500 hp, the line between high-level motorsport and a death wish was almost indistinguishable.
The Tragedy That Turned The Delta S4 Into A Time Capsule
At the 1986 Tour de Corse in Corsica, Henri Toivonen was setting a blistering pace in his Delta S4. On May 2, 1986, during Stage 18, Toivonen’s S4 plunged off a tight, guardrail-less mountain road into a ravine. The car landed on its roof, and the hot turbocharger ignited the lightweight Kevlar bodywork and mid-mounted fuel tanks located under the seats. Both Henri Toivonen and his co-driver, Sergio Cresto, perished in the fiery accident.
The tragedy sent shockwaves through the motorsport community, as it was the most fatal in a series of accidents that year. Within hours, FISA announced that Group B would be banned at the end of the 1986 season, and the planned hyper-spec “Group S” category was scrapped. The Delta S4’s competitive lifespan was cut short after just 13 months, marking the end of this great rally era.
The S4 Is Even Rarer Than We Thought
We all know that cars like these are very rare — that should come as no surprise — but Lancia’s numbers didn’t add up. Officially, homologation rules required Lancia to manufacture 200 identical road-going units. However, motorsport historians and collectors long suspected that Lancia took liberties with this.
Legend has it that when FISA inspectors arrived to count the 200 required cars, Lancia parked groups of S4s across multiple parking lots, ushering inspectors to lunch while moving the same cars to the next lot to double-count them. Today, expert consensus, supported by research from specialists like Girardo & Co., suggests that nowhere near 200 Stradales were actually assembled. It is estimated that only 65 to 100 original units were ever fully built, with many later cannibalized for competition chassis or spare parts. This historic discrepancy has made verified Stradale chassis exceptionally rare and expensive.
Delta S4 Stradales Are Worth A Lot Today
When new in 1985, a Delta S4 Stradale cost roughly 100 million Italian Lire (about $41,000), which was over five times the price of the range-topping Delta HF Turbo. But that price pales in comparison to what these cars go for today. In the modern collector market, the S4 Stradale is treated as a Holy Grail machine. Pristine, low-mileage examples regularly break seven-figure thresholds at premier auctions like RM Sotheby’s.
The most expensive S4 Stradale ever sold went for €1,040,000 ($1.18 million) in 2019, while the rally car sold for £1,636,250 (over $2 million) in 2022. High-profile sales brokered by elite classic car houses like Girardo & Co. have established the S4 Stradale as one of the most valuable road-going rally cars in history — a surviving artifact from an era of motorsport that will never happen again.
Sources: CarandClassic, RM Sotheby’s, Girardo & Co.
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