Homologation. It’s a word that will mean little to your casual petrolhead, let alone the average man or woman in the street, but it has been directly responsible for some of the most exciting, focussed and uncompromising cars ever sold to the general motoring public. It spans generations of cars and encompasses almost every form of motorsport, from Group A rally icons like the Escort Cosworth to little known curiosities like the BMW E46 M3 GTR. 

Specific details varied from decade to decade and sport to sport, but the essence of homologation was always fairly simple; the FIA (or going further back still, FISA) decreed that a certain number of road-going variants of a manufacturer’s mooted competition car be constructed, as many as 5000 individual cars in mass market formulas like Group A. This done, the car maker in question was free to go racing or rallying, though future performance-netting revisions often demanded costly homologation runs of their own, which is how we wound up with the fabled ‘Evolution’ models.

It probably won’t surprise you that everyone at Retropower is well versed in the concept of the homologation special, with most of us growing up lusting after an E30 M3, Cosworth or Sport Quattro. So with this in mind, here are 10 of our favourite homologation icons in no particular order.

The RS500 will forever be associated with a golden era of tin top racing, and prices have rocketed accordingly

Ford Sierra Cosworth RS500

There are a couple of things you need to know about the RS500; it was the product of Ford’s industrial might and steadfast commitment to going motor racing (and winning) in the middle of the 1980s, it launched the careers of a crop of tin-top drivers who’d go onto dominate the sport for much of the decade, and it was so potent, so successful that the rules were effectively changed to outlaw it. 

The RS500 could only have come from a joint effort between Ford and Cosworth (and even then only thanks to Ford’s famous motorsport director, Stuart Turner), the two firms having forged a daunting motorsport reputation in the previous decades, most famously with the Cosworth DFV, the V8 which effectively set the template for what an F1 engine should be for much of the ‘70s. 

Effectively an ‘Evolution’ version of the already potent Sierra Cosworth, the RS500 boasted the same 16v YB engine as its ‘common or garden’ relation, yet thanks to the magic of homologation and its maker’s burning desire to best its tin-top rivals, gained (amongst others) a thicker block, revised Garrett T04 turbo, enlarged intercooler, and most famously of all, a second set of 4 Bosch injectors housed on a secondary fuel rail. These were supplied ‘un-plumbed’ on the 500 road cars but could easily be activated at a later date, giving immense potential for aftermarket tuning.

The RS500 and its performance must’ve been jaw-slackening on a public road network then dominated by 60bhp Escorts and Vivas, back when a ‘hot hatch’ still constituted a single cam with some mild tuning work, but it was small beer compared to the race versions. The likes of Dick Johnson, Andy Rouse and Eggenberger coaxed well over 550bhp from the RS500s, touring car titles in Britain, Germany, Australia and Japan soon followed, and homologation legend was born. 

The Stratos came, saw, conquered, and would’ve conquered a lot more for a lot longer had Fiat top brass not intervened

Lancia Stratos

The first of a number of Lancias on this list, and arguably the most important – though probably not for quite the reason you assume. The Stratos was successful, no doubt about that; it crushed its opposition within months of its works debut in 1974, won every rally on the championship calendar bar the Safari and the RAC, and was only ‘beaten’ by internal Fiat Group politicking, when the parent company demanded Lancia make way for the more obviously road-based 131 Abarth. It won 3 titles on the bounce and was still racking up victories in private hands well into the ‘80s.

Yet the real significance of the Stratos was what it represented, it being the first car conceived, designed and built with the express purpose of going rallying. Granted, the Stratos Zero (a car we’re presently building a homage to) have existed as early as 1970, yet the Stratos HF was an almost wholly revised Bertone design and fitted with the same V6 as used in the Ferrari Dino. So yes, silverware and championship glory were all well and good, but the Stratos’s place in homologation history was truly cemented through its initial concept and what it stood for; a determination to winning at rallying’s highest level – and to hell with the costs.

The world’s first V8-powered M3 was actually a homologation racer, of sorts

BMW E46 M3 GTR

We could’ve included the far better known E30 M3 in this list of course, but then this isn’t a rundown of the most successful homologation specials, just the ones we like best, hence the GTR. It was a car that stretched the very concept of homologation to the very edge of feasibility by dint of there only ever being 6 of them made, each priced at a cool 250,000 euros when offered for sale, and in a first in the M3 lineage to be fitted with a V8.

The need to homologate said engine was the very reason for the GTR’s existence, BMW having decided that it needed extra firepower if it was to best the hitherto dominant GT Porsches in the American Le Mans Series. Aside from the P60 engine (good for 444bhp in race trim, a ‘mere’ 380bhp in road form) the GTR gained a stiffer chassis, revised aero, enhanced cooling, fully adjustable and competition spec ‘differential and clutch. It worked, and BMW was able to win the GT division in some style in 2001. 

The Delta Integrale was the car to beat from 1987 to 1992

Lancia Delta Integrale 

Lancia’s final dalliance with the World Rally Championship was also its most successful, with the Group A Delta HF and Delta Integrale winning manufactures’ titles in six years on the trot from 1987 to 1992, and taking a Lancia driver to the title four times in that same span. It was a crushingly dominant performance for Turin to sign out with, and it forced Lancia’s WRC competition to up its game considerably – hence the Japanese invasion of the ‘90s, spearheaded by Toyota with its Celica.

Much of the Delta’s early success can be put down to a mix of prudence and goods luck, as Lancia was one of the only teams with an all-wheel drive, turbocharged hatchback suited to Group A rallying in the wake of Group B’s sudden demise at the end of 1986. That said, while early wins were achieved against two-wheel drive Sierras and out-gunned Mazda 323s, the Delta proved to be an impressively versatile package, able to accept major homologation revision to remain competitive. This gave rise to the likes of the Integrale, the Integrale 16v, and for 1992, the fabled ‘Deltona,’ the ultimate iteration of the ultimate Group A Lancia. 

The Dauer 962 was a true road going Le Mans car

Dauer 962 Le Mans

Homologation was frequently stretched to extremes by manufacturers desperate to gain an advantage, and the remarkable Daur 962 was a classic case. It was based upon Porsche’s brutally successful 962, a car which had pretty much made Group C its own for a large part of the 1980s yet had been rendered uncompetitive by subsequent regulation changes. Undeterred, Dauer Racing set abut modifying the 962 for road use, the 13 cars eventually built capable of delivering 730bhp to the rear wheels through a de-restricted version of the racer’s 2994cc flat-six.

So far, so conventional (if ballistic) road car. Where things take a turn for the weird is when Porsche realised that Dauer’s efforts had effectively allowed them to exploit a new loophole in the Le Mans regulations, meaning that, once it had demonstrated its ability to swallow a small suitcase, the old stager was cleared for action once more. Its proven mechanicals and enlarged fuel tank would prove instrumental in Porsche’s eventual victory on the 1994 Le Mans, a full 6 years on from the 962’s last success. 

The 205 T16 didn’t bother to spare Audi’s blushes – it well and truly put the Quattro in the shade

Peugeot 205T16 E2

We could’ve included any one of a number of Group B cars in this list, as they were all powerful to the point of being unhinged and all underpinned by good old fashioned homologation principles, yet we’ve opted to give the Peugeot the nod here. Partly this is down to Lancia and Ford already being featured elsewhere, partly as the 205 T16 grew to become the most complete and most successful of all the Group B ‘supercars.’

It’s easy to forget that Audi’s spell of rallying dominance was actually rather brief, and that the Quattro was effectively felled from the moment the 205 T16 broke cover, midway through the 1984 season. Unlike the big, front-engined Audi with its roots firmly grounded in Group 4 thinking, the 205 T16 was evidence that Peugeot had grasped the full potential of the open-ended Group B rules; the T16 was space framed, bristled with aero and composite materials, and was powered by a transverse, 1.8L turbocharged four-pot mounted amidships and sending its power to all four wheels. 

Timo Salonen took the drivers’ title and delivered the manufacturers’ crown to Peugeot with relative ease in 1985, before Juha Kankkunen repeated the feat (albeit in more contentious circumstances) with the E2 Evolution model the following season. These results confirmed the T16 as the most successful car of the Group B era, and provided PSA with the springboard needed to dominate rally raid events for much of the early ‘90s. 

The GT-One was a homologation special, albeit one never destined for the public road

Toyota GT-One

Toyota and its Cologne based motorsport preparation arm, TTE, came up with what might be the loosest of all homologation interpretations, the GT-One. A competitor of the Porsche 911 GT1 and Mercedes Benz CLK GTR (you know, the one with a tendency to launch itself into the air midway down the Mulsane straight), the GT-One was powered by a twin-turbocharged 3.6L V8 mounted to a six-speed sequential of TTE’s own design. Just two cars were built to satisfy the GT1 regulations, both destined to be kept by Toyota and never offered for sale.

Yet the most exciting aspect of the GT-One is also one of the most mundane, its fuel tank. One of the few road-going links stipulated by the FIA re the GT1 formula concerned luggage space – there had to be room for a conventionally sized suitcase somewhere in the car. Toyota managed to convince the powers that be that the GT-One’s fuel tank counted, reasoning that the fuel cell would indeed be large enough to house a piece of luggage were they to cut it open! 

The Group A Evos proved themselves well suited to further development work as the ’90s progressed

Mitsubishi Evo 

The ‘90s were the highpoint of homologation in World Rallying, it being the dominant formula from 1987 to 1997. It birthed a crop of homologation icons, all with a very-nearly-as-bonkers road variant offered to the car buying masses, and none was more successful than Mitsubishi and its succession of Evos. It took a few years for Mitsubishi and Ralliart to really begin to land blows upon the opposition, but by the time of the Evo III of 1995 things had begun to look up for the team, not least as it’d signed one Tommi Makinen as lead driver. The Finn would go onto accrue a then record breaking haul of titles, an unbroken run stretching from 1996 to 1999.

The Evo evolved over that same span of time, successive homologation revisions giving rise to a line of focused, cult icons, the Makinen edition easily the most coveted. Mitsubishi’s 4G63 remained largely unchanged throughout (despite being spun round 180 degrees in the jump from Evo III to IV), its long stroke configuration giving it an advantage when the FIA mandated a 34mm turbo restrictor from 1995. 

The Group A Evos were effectively put on notice when the World Rally Car regulations were introduced in 1997, though the same basic package which had first seen the light of day back in 1993 was able to keep on winning until the early noughties.

The naturally aspirated Manta 400 fought a brave rear guard action against the Group B supercars

Opel Manta 400 

The Manta 400 was a far more conventional competition machine than the others listed here, but then this is a list of homologation specials selected by Retropower, and as such its inclusion shouldn’t be all that surprising! What the 400 lacked in turbocharged ‘shove’ and all-wheel drive traction it partially made up for in flair; drivers like Jimmy McRae, Bertie Fisher, Austin McHale and Russel Brookes forged careers through ‘Manta hustling,’ and the image of a 400 being hurled along Manx lanes is among the most evocative in the history of British rallying. 

The 400’s inclusion on this list can’t have been hurt by us having built a number of Mantas over the years, including this RB25-powered 400 replica. 

Alfa Romeo bent the BTCC rules to breaking point with the 155

Alfa Romeo 155 Silverstone 

There’s little to top a spot of motorsport skullduggery, even more so if it involves a homologation special, hence why the Alfa Romeo 155 Silverstone makes the cut. Homologated into the British Touring Car Championship in time for the 1994 season, the Alfa 155 Silverstone (as the model was soon christened) was sold with an adjustable front splitter and spoiler in the boot. This was merely a means of subverting the letter of the law, and it was to the surprise of almost everyone in the BTCC paddock when the Alfa Romeo team turned up for the first round of the BTCC season, Thruxton, with adjustable aero on the cars of Gabriele Tarquini and Giampiero Simoni. The result was near total Alfa Romeo domination of the first half of the season, plus a chorus of complaints from the other, aero-less teams. 

The drama reached its climax at Oulton Park, when the 155s were ordered to run with their wings in the fixed position. Latin toys were subsequently thrown from prams and Alfa Romeo temporarily left the series in protest, returning later in the season but forced to run with the aero ‘down.’ Not that it mattered, not once Tarquni had there bit between his teeth, and he took the title with relative ease. 

The Sport Quattro was a fundamentally flawed machine, granted, but one with buckets of charisma

Audi Sport Quattro

Time caught up with the original Audi Quattro with indecent haste and by 1984 it’d begun to show its age and relative lack of finesse. All-wheel drive and forced induction might’ve been enough to see off Group 4 hangers-on like the Stratos, the Escort and the 131 Abarth, but the car’s nose-heavy nature and relatively basic four-wheel drive system meant that it was increasingly outclassed by newer Group B hardware, the 205 T16 in particular.

Something needed to be done to readdress the balance, and fast. The issue was that Audi was hampered by the Quattro concept itself, which was based upon the system being applicable to road cars, and road cars fitted with heavy, forward-mounted five-pots at that. A complete re-design with the engine placed in the middle of the car was therefore out of the question, which is how Audi Sport came to develop the Sport Quattro.

A somewhat desperate attempt to cure the big Audi’s ponderous, under-steer ridden handling, the Sport was essential a chopped down ‘long’ Quattro with a full 12.5in chopped from its length, plus additional Kevlar and extra power. Audi Sport engineers also increased the rake of the windscreen, an attempt to making pinpointing corners that bit easier in the gloom of a British forest or a late night blast over the Col de Turini.

These were big changes and made the Sport a more competitive prospect, at least on paper. The issue was that the shortening process had had mixed results, certainly in terms of on the limit handling. Indeed, Stig persisted with the old A2 until he’d put his 1984 drivers’ title beyond doubt, and was only able to win once with the Sport, the car’s sole WRC success on the Ivory Coast Rally. In any case Audi had moved onto bigger and better things by this point, and the S1E2 Quattro would make its debut the following year.

Click through to learn more about our own tribute to the ultimate Audi, the Retropower Sport Quattro.

 

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