The cars transformed by a new engine

If you can’t immediately bring one to mind, the Bugatti Chiron is a good example. There are also many cars which were more or less ordinary in their original forms but became more desirable in one way or another because a new engine was added to the range, or because an existing engine became available in a significantly altered form.

Here are 28 models which we believe are part of the second category, listed in alphabetical order.

The AC Ace roadster was introduced in 1953 and was fitted with several engines during its production run, the most powerful being a 2.6-litre Ford straight-six. Its handling made it an effective road-legal competition car, but over in Texas Carroll Shelby (1923-2012) reckoned it would be better if it had a lot more power.

Rather than dismissing this thought and moving on to something else, he created the Cobra, a reworked Ace with a Ford Windsor V8 engine initially measuring 4.3 litres and later 4.7. The Cobra proved to be a mighty car in racing, even more so when it went into a new generation with a 7.0-litre Ford FE V8 under the bonnet.

The original A110 (not the current model launched in 2017) was initially powered by Renault’s little Cléon-Fonte engine. This was later replaced by the larger Cléon-Alu, which had made its debut in the Renault 16.

It’s difficult to imagine the 16 being an effective competition car, but its engine turned the A110 into a world-beater. In 1973, Alpine thrashed the opposition in the inaugural World Rally Championship, winning six rounds and finishing the season with 147 points to Fiat’s 84 and Ford’s 76.

Audi has a lot of history in this area. Most of its models have high-performance S and – more excitingly – RS derivatives whose engines are far more powerful than those in the regular versions.

The A4 is a case in point. Its RS 4 equivalents have always had splendid engines. Perhaps the finest, and certainly the best-sounding, was the screaming 4.2-litre V8 also used in the Audi R8. It produced over 400bhp, well in advance of what could be expected from any other A4.

Every Q7 is an imposing beast no matter what powers it, but Audi went to new and unexpected levels when it fitted the large SUV with a 5.9-litre diesel V12. This engine, which has never been used in any other production car, produced 493bhp, which was enough to push the 2635kg Q7 from 0-62mph in an astonishing 5.5 seconds.

Fortunately, the brakes and suspension were up to the task, but acceleration like this was still exhilarating or – depending on your mood – alarming. And it didn’t come cheap. Priced just short of £100,000 in the UK, the 6.0 V12 TDI, as it was branded, cost around £40,000 more than the next most expensive Q7. Data suggests that 21 reside on British roads today.

Almost by definition, every M3 has had an engine which transforms it into something quite different from the regular BMW 3 Series. This was particularly true of the generation sold between 2007 and 2013, which was powered by the 4.0-litre (and, for the GTS variant, 4.4-litre) S65 V8.

A multiple award winner, the S65 made this M3 the first to produce over 400bhp in standard form. It wasn’t the only V8 used in an M3, because a tiny number of earlier cars were fitted with one too, but it was the only engine of this type used for every example in any generation.

In most forms, the CT6 was a full-size luxury saloon. The CT6-V was that too, but it was also a very impressive performer thanks to its 550bhp 4.2-litre V8 engine, commonly known as the Blackwing. It was also available in the CT6 Platinum, producing 500bhp.

These cars were sold only in the 2019 model year. The entire CT6 range was discontinued shortly afterwards, partly due to poor sales and partly because the Detroit-Hamtramck plant where every version was built was retooled to produce electric vehicles instead. The Blackwing name has been used again for the most powerful versions of the CT4 and CT5, but neither of these is fitted with the Blackwing engine.

Since the Corvette is one of the most popular sports cars in history, it seems strange now that the first-generation version did not sell at all well when it was introduced in 1953 with a straight-six engine. Two years later, it became available with the new Chevy Small Block V8, originally in 4.3-litre form but later extended first to 4.6 and later to 5.4 litres.

It was almost as if this was what the American public had been waiting for. Corvette sales rose dramatically, and a car which might have been abandoned at an early stage remained in production until 1962. Six decades later, its latest descendant is still doing well, and still powered by a V8 engine.

The current Challenger (the third distinct model to bear that name in over half a century) has been sold in several quite startling forms, with enormous power outputs. Even in that context, the SRT Demon variant, sold only in the 2018 model year, is outstanding.

Its 6.2-litre supercharged V8 engine is the most powerful ever fitted to any road-legal Dodge, or indeed any Chrysler. On regular 91-octane petrol it produced 808bhp, but with the optional Demon Crate package and running 100-octane race fuel its output reached 840bhp. The lower figure has more or less been equalled by the current Challenger SRT Super Stock, but that car has slightly less torque.

The 500 was originally available with a variety of four-cylinder petrol engines. Three years after its launch in 2007, Fiat added the two-cylinder TwinAir, the first engine designed from the start to use the remarkable MultiAir technology which had previously been added to existing units.

Getting anywhere near the official fuel consumption figures was quite a challenge, and there was a lot of vibration until Fiat decided to add a dual-mass flywheel. But the popularity of the 500 has always been due to its cuteness more than anything else, and with the TwinAir purring away it sounded as cute as it looked.

Most first-generation Cortinas were powered by either 1.2- or 1.5-litre versions of the pre-crossflow Ford Kent engine. In 1963, a year after production began, the car was transformed by a new power source, resulting in the epoch-making Lotus Cortina.

In its nether regions, this engine was basically the same as a Kent, but it had a completely different cylinder head. Known as the Lotus Twin Cam, it had made its debut the previous year in the Elan sports car. For the first time, here was a Cortina with a power output of over 100bhp. Further modifications brought great success in racing and rallying, in addition to the standard car’s appeal as the 1960s equivalent of a hot hatch.

As with the Cortina, the Lotus Twin Cam engine turned the mainstream first-generation Escort into something altogether more special, but the bar was raised much higher when Ford launched the Cosworth BDA-powered RS1600 in 1970.

Like the Twin Cam, it was based on the Kent engine, and in standard form it wasn’t much more powerful. However, with four valves per cylinder it was far more responsive to tuning, with the result that the Mk1 Escort became one of the great rally cars of the early to mid 70s. Even today, hearing a fully tuned RS1600 screaming through a forest stage is a memorable experience.

The mid-sized European Ford between the Cortina and the Mondeo was available in its earlier days with a variety of engines, none of them particularly dramatic with the possible exception of a large V6. The game-changer was the 2.0-litre four-cylinder unit which powered the Sierra RS Cosworth from 1986 onwards.

At its heart, it was quite humble, being based on the well-established Pinto engine. A turbocharger and a 16-valve cylinder head made quite a difference, though. Even in its least potent form it produced over 200bhp, which no other Sierra engine could even approach. Further modified for competition use, it could reach outputs on the far side of 600bhp.

Honda has been producing Type R variants of its Civic since 1997, and since 2001 they have all been powered by a 2.0-litre engine. For 15 years, these were known for their remarkable power, their ability to rev well beyond 8000rpm and a certain lack of oomph before the VTEC variable valve timing switched from tea-with-the-vicar to the-zombies-are-coming mode.

Honda changed the game entirely in 2015 when it added a turbocharger. The engine was now limited to a relatively modest 7000rpm, but suddenly there was plenty of mid-range power, and the peak figure shot up to 306bhp. After some mild tweaking, it was raised further to 316bhp.

The Thema was a luxury saloon based on the same platform also used for the Alfa Romeo 164, Fiat Croma and Saab 9000. Two years after it was launched, Lancia added an outstanding version called the 8.32, named after the number of cylinders and valves in its engine.

At 2.9 litres, this wasn’t quite the largest unit fitted to the Thema, but it was by far the most powerful. Derived from the Ferrari Dino V8, it produced 215bhp, a full 40bhp more than the 3.0-litre Alfa Romeo V6 which it demoted to second place in the range.

Launched in 1965, the Europa was a very early example – though by no means the first – of a mid-engined road-going sports car. To begin with, it was powered by the Cléon-Alu engine from the Renault 16, and also used that car’s transaxle which, unlike any transmission available from usual supplier Ford, could easily be adapted to suit the mid-engined layout.

Lotus continued using the transaxle through the Europa’s production life, but it eventually swapped the engine for its own Ford-based Twin Cam. Power outputs accordingly shot up, initially to 105bhp and later to 126bhp, giving the Europa far more straightline performance than it had started out with.

Replacing a powerful petrol engine with a much less powerful diesel may seem like a backward step, but in this case it was the right thing to do. The CX-7 SUV was initially available only in the UK with the 256bhp 2.3-litre petrol engine also found in the high-performance Mazda3 MPS and Mazda6 MPS. Everyone knew this was a bad idea – including, they would quietly admit, Mazda’s British representatives.

Two years later, in 2009, that engine was dropped in favour of a 2.5-litre diesel. The price went up, and the power output dropped by a startling 85bhp, but the CX-7 was now subject to £190 less Vehicle Excise Duty each year and was, according to the official fuel economy figures, 10mpg less thirsty. A previously almost unsellable vehicle had now been transformed into something that suited its target customers.

The third-generation A-Class was mostly available with a variety of engines with power outputs in the 100-210bhp range. One year after launch, though, Mercedes introduced the four-wheel drive A 45 AMG variant (subsequently renamed Mercedes-AMG A 45).

The difference this made to the car’s straightline performance was phenomenal. The highest power output in the range had now shot up by 70% to 355bhp, and that was only the start. Following a revision, it rose still further to 376bhp. Today’s fastest A-Class has a different but conceptually similar engine which produces 416bhp.

In a spectacular example of what we called “Mercedes’ every-engine-in-everything product planning,” the R-Class became available with a 503bhp 6.2-litre V8 engine a year after its launch.

As a large luxury MPV, it was well suited to powerful engines, but this was a whole new ball game. The big V8 produced 503bhp, which was far more than anyone needed – or, apparently, wanted. Sales were minimal, and the R 63 AMG, as it was called, disappeared from the price lists very quickly.

The MGB roadster was launched in 1962, and a coupe version called the MGB GT came along three years later. In an attempt to create a high-performance variant, MG first fitted a 2.9-litre straight-six engine and called the result MGC, but this was unsatisfactory and was abandoned after just two years.

A second attempt followed in 1973. This time, MG created the MGB GT V8 by fitting the 3.5-litre Buick-derived Rover engine into the coupe. It didn’t last much longer than the MGC had, but by general consent it was a far superior car.

This was a very mild but still valid example of the principle we’re discussing. The 6 was designed as an upmarket alternative to the Renault 4 which was fitted at its launch in 1968 with the same immediate post-War Billancourt engine, even though the larger and more powerful Cléon-Fonte had been available for six years.

In 1970, Renault did the right thing and added the Cléon-Fonte to the range. With this engine, the 6 still wasn’t especially quick – and didn’t really need to be – but it was at least acceptably so. As we said in a 1974 road test, there was “no doubt that Renault’s engineers got their sums exactly right” at the second attempt.

The first few versions of Renault’s hottest Clio were all powered by a high-revving, naturally-aspirated 2.0-litre engine. This policy changed dramatically in 2013, when Renault switched to a 1.6-litre turbo co-developed with Alliance partner Nissan and producing similar power (197bhp).

There was no doubt that the Clio’s character had been transformed. The question was whether this was a positive or a negative move. There were those who felt the superior mid-range performance was a major improvement, but we reckoned that “all the previous car’s impish zip has been sucked mercilessly from the bone”.

Saab fitted nothing but two-stroke engines to its cars all the way from the launch of the 92 in 1949 until nearly halfway through the production life of the 96 (the 92’s second successor) 18 years later. At this point, it switched to a four-stoke V4 developed by Ford of Germany.

It wasn’t one of the world’s great engines, but it was more powerful than anything Saab had used in the past. Crucially, it also didn’t sound like a wasp trapped in a tin can or emit clouds of smelly blue smoke. The 96 lasted until 1980, which it certainly wouldn’t have done if Saab had persevered with the two-stroke.

The story of the Sunbeam Tiger almost exactly mirrors that of the slightly earlier AC Cobra. Both cars were suggested by Carroll Shelby, who (in the case of the Tiger) thought there was nothing wrong with Sunbeam’s Alpine sports car that couldn’t be fixed by giving it more power.

As with the Cobra, the Alpine was converted to accept the Ford Windsor engine (4.3 litres at first, later 4.7) and given a suitably aggressive name. This time, though, there would be no progression to a larger Ford V8.

Of the several cars known as Vanden Plas Princess, the one we’re interested in here was the large, Farina-designed saloon which was almost identical to models produced by Austin and Wolseley. All were powered by a 2.9-litre straight-six engine, but only the Princess was taken a stage further.

In 1964, it was given a new name – Princess R – following several revisions, the most dramatic being the fitment of a 3.9-litre engine developed by Rolls-Royce. The power output jumped from around 120bhp to 175bhp, which made the Princess far quicker than before, though given the nature of the car it’s likely that more effortless high-speed cruising was considered more important than sharper acceleration.

The Carlton GSi was a fine car with excellent handling and a strong 3.0-litre 24-valve engine. It was also the basis of that Wagner opera on wheels, the Lotus Carlton. Despite claims to the contrary elsewhere on the internet, every example of this model came off the Opel production line in Rüsselsheim as a standard GSi before being shipped to Lotus in Hethel for a conversion which lasted 150 hours.

The alterations included raising the capacity of the six-cylinder engine from 3.0 litres to 3.6 and fitting two Garrett turbochargers. Power output accordingly shot up from the original 204bhp to 377bhp (if the engines was fed with sufficiently high-octane petrol), and the straightline performance improved to such an extent that there were calls for the car to be banned.

The first two generations of Golf R were known as R32, a reference to their 3.2-litre V6 engines. They were quick and sounded fabulous, but that engine was very heavy and mounted almost entirely ahead of the front axle, which created major handling problems in the original version. The next one was better, but still occasionally troublesome, especially over a series of closely-spaced crests.

For the generation after that, Volkswagen ditched the 32 part of the name and fitted a turbocharged 2.0-litre four-cylinder. This was more powerful, but crucially it was also lighter. The handling issues disappeared completely, and the R became the splendid hot hatch it should have been in the first place.

The Passat introduced in 1997 was (a former owner writes) a worthy but not particularly exciting car available with engines which could mostly be described as straightforward – except one. This was a 4.0-litre W8, essentially two 2.0-litre V4s mounted on a common crankcase, the only engine of that type ever fitted to a production car.

Available from 2001, it produced 271bhp, making it the most powerful engine used in a Passat of that generation by over 80bhp. Despite its outstanding features, it sold very badly, and the project was soon abandoned, which may have been what VW expected to happen.

In another piece of extravagant engine policy, Volkswagen added a 6.0-litre W12 to the Touareg two years after the big SUV was launched. This engine was nearly as rare as the W8 fitted to the Passat, but was also used in the Audi A8, the Bentley Continental and the VW Phaeton.

Once again, this engine blitzed all the others in the range in terms of performance, with a maximum output of 444bhp. VW initially planned to build only 500 examples of this particular Touareg, but continued production when it proved to be surprisingly popular.

At the time of its launch in 1948, the Minor was fitted with a 918cc engine based on a Wolseley design which was already 20 years old. It was extremely unlikely that this unit would last, as the car did, until as late as 1971. In fact, the change happened very early in the Minor’s career. In 1952, Morris was brought together with its former arch-rival Austin in the British Motor Corporation.

This gave Morris access to the new BMC A-Series engine, which had just been introduced in the Austin A30. Despite being smaller, at 803cc, the A-Series had similar power to the engine it replaced, and far more scope for development. By the end of Minor production, it was being used in 1098cc form, and still had nearly three decades more life left in it.

Most Sunbeams were fitted with either 1.3- or 1.6-litre versions of the engine used in the Hillman Avenger or a 928cc unit derived from that of the Hillman Imp. The outlier was a 2.2-litre 16-valve Lotus motor, part of a range which was used both in the Jensen-Healey sports car and several models produced by Lotus itself.

With a power output of 150bhp, the Sunbeam Lotus was a formidable road car, but that wasn’t its main purpose. The idea had been to attract publicity for the brand through motorsport, and it worked. Just before four-wheel drive turned the whole scene upside-down, the Sunbeam Lotus was competitive enough to earn Talbot the Manufacturers’ title in the 1981 World Rally Championship.

The Chevette was initially a small hatchback (though saloons and an estate followed) based on the Opel Kadett. Nearly every version was fitted with a 1256cc engine, but Vauxhall, like Talbot with the Sunbeam, decided that a more powerful version intended for rallying would be good for publicity.

There was no way that the original engine would be suitable for this, so Vauxhall took its 2.3-litre Slant-4 engine, added a 16-valve cylinder head and put it under the bonnet to create the Chevette HS (pictured). (Early rally cars were fitted with a similar head developed by Lotus, but this was soon banned.) The same mechanical arrangement was used for the later HSR, which had several fibreglass panels, including wide front and rear wings which gave the car a very dramatic appearance.