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Not only is the Lancia Delta S4 Stradale among the rarest of the road-going Group B homologation specials. We reckon it’s also the best of the bunch. For too long these ultra-rare Lancias have been shrouded in mystique. Using this fabulous example we recently sourced for a client, we’re going to unpack the Delta S4 Stradale and show you why it’s so desirable…

The Lancia Delta S4 Stradale boasts a fearsome reputation which truly precedes it. The unfortunate thing is, not many people know a lot about the Group B unicorn. It is a car we understand pretty well here at Girardo & Co. headquarters. Since we set up shop six years ago, we’ve found new homes for over 15 percent of the entire production run… depending on which numbers you believe.

Lancia and Abarth were required by the FIA to build 200 road cars in order to allow the full-fat Corsa variant to compete in the World Rally Championship. But we all know it didn’t. The numbers vary drastically from source to source, but we reckon as few as 70 Delta S4 Stradales ever left the factory.With such a wealth of knowledge about and first-hand experience of the ultra-rare Delta S4 Stradale, we thought producing an in-depth guide about these lust-worthy Lancias, showing what distinguishes the model and highlighting why it’s so desirable in today’s collector car market, would prove useful to our clients, friends and followers. We hope you enjoy digesting it as much as we did researching and producing it.

First and foremost, we think it’s wise to outline the popularity of rallying in the 1980s. A kaleidoscopic explosion of speed, noise and very real, very imminent danger, Group B deservedly drew a greater number of viewers than Formula 1. That’s why, despite the inherent risks, automotive brands could warrant funnelling enormous amounts of money into their WRC programmes, which were oriented around their otherwise modest cars you could find in the showrooms.It’s also why, from a commercial point of view, Lancia (which, let’s not forget, was representing Italy on the world stage) simply had to up its game in 1985 if it wanted to win another title. The dominant success of 1983 was but a distant memory and Audi and Peugeot had proven that powering all four wheels was a quicker means of sending a rally car down a special stage than just two, a la 037 Rally. Decisive action was needed. In a bid to revive its incredible sporting heritage, Lancia greenlit the blank-sheet development of the 037’s new four-wheel-drive Group B successor, based loosely on the flagship Delta HF Turbo.

‘SE038’. That was the internal codename for the Lancia Delta S4, an all-new car which trod a technological path very different to its rivals. The development was entrusted entirely to Abarth, whose creative, bullish and trailblazing engineers poured their everything into the project. Suffice to say, there was not a plan B.In the mid-1980s, newfangled technology such as four-wheel drive and electronic ignition was in its infancy and Lancia’s competitors had stolen a march. They say imitation is the sincerest form of flattery. But without the knowledge to even copy its competitors, Abarth was forced to innovate. And innovate it most certainly did.

“They say imitation is the sincerest form of flattery. But without the knowledge to even copy their competitors, Abarth was forced to innovate. And innovate it most certainly did.”

The road-going Lancia Delta S4 Stradale was the first car to be ‘twin-charged’, that is fitted with both a supercharger and a turbocharger to better distribute the engine’s torque and reduce lag. It boasted an incredibly clever electronic injection and ignition – genuine Formula 1 technology at the time. The car’s spaceframe chassis was designed by computer. And the four-wheel-drive system was operated by three differentials. The result was a car which pushed the technological envelope to its boundaries and, frankly, made the ‘latest and greatest’ supercars from the likes of Ferrari and Lamborghini look antiquated.

The very first Delta S4 Stradale prototype was chassis number 003, the car Lancia also used for homologation and for its marketing material. Following a trip to Elba Island in September of 1985 for a journalists’ preview, the car was officially revealed to the public at the Turin Motor Show the following month.Following a 34-month gestation period and what can only be described as some wishful counting on the part of the FIA officials, the Delta S4 was homologated on 1 November 1985 with the code DGM51831OM. Said code was displayed on the chassis plate in the door sills of the Stradale.A few short weeks later, Lancia Martini Racing’s drivers Henri Toivonen and Markku Alén vanquished the opposition to score a one-two victory in the Lombard RAC Rally of Great Britain, the S4’s competitive debut. To put the rally car’s astonishing performance into context, an S4 turned a lap of Brands Hatch during a special stage which would have put it halfway up that year’s Formula 1 grid. It was an extremely encouraging result for the marque, which looked to be in good stead ahead of its 1986 WRC campaign.

That the Lancia Delta S4 Stradale pioneered several technological features that today we take for granted is no overstatement. So just what was going on beneath the idiosyncratic surface?The car’s skeleton is an intricate lattice frame of welded steel tubes, which was designed by computer and built at CECOMP (the Centro Esperienze Costruzione Modelli e Prototipi) in Turin. Around 200mm longer than the 037’s and incorporating the safety roll-bar, the chassis was designed first and foremost to be very light and very rigid. However, the spaceframe construction was also preferred because of the easy access it afforded to the mechanical components – essential for speeding up repair times on rallies.At the corners of the car, Pirelli-shod 16-inch Speedline wheels inspired by the 1930s Bugatti Royale conceal ventilated Brembo disc brakes. The suspension is independent, with double wishbones, coil springs and hydraulic shock absorbers.

The Lancia Delta S4’s heart is where the headlines were really written. Designated with the type number 233 ATR 18S, the engine’s development preceded the completion of the chassis. As a result, the powerplant was installed in a crudely modified Lancia 037 Rally. The frankly terrifying contraption was dubbed ‘Mazinger’ in Turin after the famous Japanese Manga character.An inline-four with an alloy head, four valves per cylinder and dry-sump lubrication, the engine was mounted longitudinally in the middle of the car. With a displacement of 1,795cc, the S4 was permitted to compete in the 2,000–2,500cc class after the FIA’s mandatory multiplier of 1.4 designated for turbocharged competitors.The engine’s patented twin-charging system utilised the Abarth R18 Volumex supercharger from 0–4,000rpm and the KKK K26 turbocharger from 4,000rpm-onwards. The Stradale was fitted with a 30-percent smaller turbocharger than the rally car, the wastegate of which was controlled electronically. The power delivery was controlled by an incredibly sophisticated electronic injection and ignition system by Weber and Magneti Marelli, which relied on RAM memory. The result was a reduction in fuel consumption and emissions, less turbo lag and increased drivability.

A five-speed ZF transmission sent the engine’s power to all four wheels via three differentials. The centrally mounted Ferguson differential utilised a viscous joint to transfer 30-percent of the power to the free front differential and 70-percent to the limited-slip rear differential. Performance was rated as follows: 250bhp at 6,750rpm, 215lb-ft of torque, 0–62mph in six seconds and a top speed of 140mph.The S4 Stradales’ naked chassis’ were pre-assembled by CECOMP, before being sent to the coachbuilder Savio in Turin, which painted and fitted the polyester resin bodywork. At this point Savio also installed the interior, windows and lights. The Lancia workshop was the next stop in the production process, where 34 skilled engineers fitted the mechanical componentry, including the engines, which were pre-assembled by Abarth, by hand. Amusingly, the S4 Stradale chassis’ rolled down the production line on temporary Ferrari space-saver wheels – the same type which accompanied each car as a spare. Abarth was then the cars’ final destination, where testing and type approval was undertaken.

From a visual point of view, the Delta S4 Stradale clearly hails from the school of function-first design. Styled originally by Renato Sconfienza and finished by the architect Bruno Giardino, it’s an interesting shape which was honed after thousands of hours of testing in Fiat’s wind tunnel. For a rally car, that was a real rarity at the time.

For commercial reasons the car needed to resemble the regular production Lancia Delta HF Turbo, though in reality, the windscreen, front grille and rear lights are the only common features. With a bulky and powerful engine amidship requiring easy stage-side access and, of course, a great deal of cooling, the bulk of the body’s visual mass is clearly at the rear of the car. Take those large cooling ‘ears’ aft of the cabin, for example, which force feed air to the two intercoolers.However, great lengths were taken to ensure the rear of the car remained cohesive to the overall design. The side windows were extensively tweaked, for example, to ensure the car looked slim from afar, while the nose was made to look sharp and sporty, akin to the conventionally beautiful 037 Rally the S4 succeeded. Whereas the S4 rally variants boasted bodies crafted from aerospace-grade Kevlar and carbon-fibre, the Stradales’ were made from less expensive polyester resin.

Road-going Group B homologation specials are not exactly known for their superior build quality. The S4 Stradale is different. And nowhere is this more obvious than the cabin. In order to broaden the model’s real-world appeal (and perhaps justify the eye-wateringly high asking price), the engineers in Turin went to town refining the interior.

“In order to broaden the model’s real-world appeal (and perhaps justify the eye-wateringly high asking price), the engineers in Turin went to town refining the interior.”

Beautifully trimmed in supple and strongly scented Alcantara, suede and leather, there’s plenty of space, the driving position is nowhere near as comical as some other Italian supercars from the same era and outward visibility is good thanks to the blanked off roof intake (the Stradale’s engine simply didn’t require as much cooling as the rally car’s). The latter also means there’s a convenient luggage shelf at the rear, accessible via the glass rear-window hatch.

Proper glass all round quietens both the buzz of the engine and the road noise, while air-conditioning (a bespoke system developed by Diavia with the help of the University of Genoa) and clever pneumatic power steering further luxuriate proceedings. Did we mention the seats? Designed by Zagato in Milan, they were described by Lancia in its 1985 press release as ‘anatomical’, though we think the word sculptural is more applicable. Remarkably, they’re even more comfortable to sit in as they are pleasurable to look at. A fun fact: the seats’ structural form wound up in the Aston Martin V8 Zagato.

Other neat interior features include the gear lever directly inspired by that on the pre-War Lancia Lambda, the onboard trip computer, the factory electronic immobiliser and the hidden Alcantara storage pouch on the bulkhead between the two seats.

Marketing and distribution of the S4 Stradale were entrusted to Lancia’s dealer network. In spite of Group B’s popularity and the technological prowess of the car, the eye-watering 110.7m-lire price tag proved a bitter pill to swallow for most. To put that figure into context, you could have bought five Delta HF Turbos for the same money in 1985. Five! Perhaps inevitably, many S4 Stradales remained at the factory or in Lancia showrooms for many months. In fact, we’ve encountered examples first registered as late as 1990.

A small number of ‘options’ were available, initially from Abarth directly with the express permission of Fiat, but later as a means of increasing the desirability of unsold cars to potential customers. They included a selection of alternative colours (black, pearl white, metallic grey and green), different shades of Alcantara, leather upholstery, Corsa-style wheels and a period Potenziato performance upgrade to 300bhp.

The optional extras were just that – extras. All the cars were originally finished in standard specification, that is metallic cherry red over beige Alcantara. like the example pictured here at Belchers Farm. Those admittedly few and far between cars earmarked for options were returned to their respective specialists to be modified. Accompanying each Lancia Delta S4 Stradale were a detailed owner’s manual, a tool roll, a jack and a Ferrari 308 spare wheel. We can vouch that finding a car today with all of the above is very rare.

Lancia and Abarth’s records from the 1980s are, as far as we know, non-existent, so the following serial numbers are what we use here at Girardo & Co. to identify and authenticate a Delta S4 Stradale.

Number: Chassis stamping | Location: On the rear right-hand-side of the bulkheadNumber: Chassis plate | Location: Affixed to the passenger door sill Number: Engine stamping | Location: Stamped into the driver's side of the engine block Number: Savio number | Location: Beneath the front crossmember

Girardo & Co. specialist Davide De Giorgi, who grew up in Turin just a stone’s throw from the Lancia factory, shines a light on what the Delta S4 Stradale is like from behind the three-spoke Momo steering wheel, what makes the car so desirable to today’s collectors, and what to watch out for if you’re considering adding one of these Group B specials to your stable.

“The Delta S4 was Group B at its most unadulterated and extreme. An endlessly romantic era which pushed man and machine to their limits. This car is a great enabler – a car without which the hallowed Corsa would not have been able to take the starting ramp.“My father used to drive me to school in Turin and we’d pass a man commuting to il grattacielo, the Lancia headquarters, in a Delta S4 Stradale every day. It was an impressionable car for an impressionable child like me. I loved its quirkiness and the fact that from a distance it didn’t look like a supercar but the closer you got the more its performance intentions became clear.“In my opinion it’s the interior which edges the S4 above its homologation contemporaries. It’s a truly great place to sit. The Zagato seats are the perfect blend of supportive and comfortable, the three-spoke Momo steering wheel is perfect in every respect and the various Borletti dials are all so legible and beautifully judged. So period. So eighties. So cool.

“The Zagato seats are the perfect blend of supportive and comfortable, the three-spoke Momo steering wheel is perfect in every respect and the various Borletti dials are all so legible and beautifully judged. So period. So eighties. So cool.”

“It’s the sense of urgency that strikes you most when you start properly leaning on the car – its zips from corner to corner like a scalded cat, and if you can bring yourself to push through the slightly disconcerting vibrations approaching the red line, you’re rewarded with another dollop of boost that really sends the car flying. The steering is a triumph, despite its assistance, and loads up beautifully in quick corners. The pedals are also placed perfectly for heel-and-toe downshifts.“These cars are now so elusive and so sought-after that should you find one, my best advice would be to have its authenticity verified by us here at Girardo & Co. and, for want of a better phrase, jump on it. A client of ours is using the S4 Stradale we sourced for him a lot, and he tells me that people still largely don’t know what it is. That mystery is certainly some of the appeal – it’s a car that only people who really understand the history will appreciate. The real connoisseurs.”

In our opinion, the Lancia Delta S4 Stradale is the very best of the road-going Group B homologation specials – cars which have understandably enjoyed a meteoric rise through the market in recent years as those who watched Group B with their jaws ajar have grown old, wise and wealthy enough to appreciate their rarity and historical significance and, of course, indulge.

When Henri Toivonen and his co-driver Sergio Cresto tragically perished after crashing their Delta S4 Corsa on the Tour de Corse in 1986, the death knell had all but sounded for Group B. But the fearsome and intimidating reputation which by proxy was passed down to the Delta S4 Stradale is, in reality, worlds away from the reality. This is a beautifully resolved and incredibly approachable sports car which is teeming with then ground-breaking technology which you really can feel working beneath you. It’s an embodiment of all that was once great about the daring and innovative Lancia marque. 

1,759cc twin-charged four-cylinder twin-cam 16-valve Tipo 233 ATR 18S engine, dry sump and longitudinally mounted amidshipKKK K26 turbocharger and Abarth Volumex R18 supercharger, two air-to-air intercoolersWeber-Marelli IAW 018 electronic ignition and fuel injection250bhp at 6,750rpm and 215lb ft at 4,500rpm0–62mph in 6sec, 140mph VMAXFive-speed ZF gearbox, dog-leg firstCentral Ferguson viscous coupling differential – 30/70-percent power split front to rearFront Hewland differential – freeRear Hewland differential – 25% lockedCECOMP tubular steel chassisPolyester resin body built and assembled by Savio in Turin1,200kg dry Photos: Robert Cooper for Girardo & Co. Click Here to discover more about the 1985 Lancia Delta S4 Stradale pictured in this feature, which we recently sourced for one of our clients. If you’d like to add one of these ultra-special Group B homologation unicorns to your stable, don’t hesitate to contact us.  Reference Points is a new series of extensively researched features here on in which we will be exploring the most significant historic road, competition and rally cars in detail, showing what distinguishes them, from both a visual and mechanical point of view, and why they’re so desirable in the context of today’s collector car market. Click Here to view other Reference Points features on