The Story of the BMW M8 Prototype – The V12 M-Car That Never Was

Back in 1990, BMW could've released this magnificent M8 - but unfortunately, they never.

3y ago

Usually when a car maker lines their sights up to take aim at Ferrari, they inadvertently end up shooting themselves in the foot. Many manufacturers have attempted to take on the supercar goliath over the years, living to tell the tale of just how badly they lost.

In the early 90's however, BMW were lining up something truly extraordinary that genuinely looked as though it could make the prancing horse fall at a particularly high hurdle. It was a hyper-GT car that wasn't just going to be faster and more powerful than anything Ferrari had in that domain – or any domain, for that matter – at the time, but would also be one of the most powerful and fastest cars on Earth. That car was the stillborn BMW M8. And this is the story of that mythical creature.

Back in 1984, BMW proceeded to create what would sit pride of place at the very top of their range. A premier luxury-performance coupe that would attract affluent clientele with irresistible allure. And in 1989, it was unveiled to the world at the Frankfurt Motor Show: the BMW 8-Series.

It had everything the budding stock-broker needed: a V12 engine, comfy seats, and most importantly of all, a car-phone to enable the yuppie driver to phone their place of work to tell someone else to plunge the globe into a financial apocalypse from the comfort of their own success-mobile.

Immediately upon its release, the 8-Series was looked upon by a number of influential individuals as the base for something a bit mind-blowing. The individuals in question were engineer and Ketchup enthusiast Karl-Heinz Kulbfell, engine specialist Paul Rosche, and chassis and earthquake expert Gerhard Richter.

Their objective was to create the ultimate performance version of the 8-Series, which under BMW's authority, would wear the fabled 'M' badge. And so, in the minds of just a handful of people, the BMW M8 had become a foetus.

As is the way with any performance project, they started by looking at the engine. The 8-Series was launched with a 5L normally aspirated V12 engine in the 850i model. The engine used just a single overhead camshaft, and 2-valves per cylinder. As a result, the 850i produced 296bhp, which isn't particularly impressive considering its large displacement.

By comparison, the V12 that sat under the M8's out-stretched bonnet was a complete and utter monster. The cylinder head accommodated a much needed DOHC and 4-valves per cylinder - but rather more interestingly, the M8's V12 had a capacity of 6.1 litres.

It's at this point that a number of you will probably be connecting a series of mechanical dots. After all, there was another car in the early 90's that was powered by a BMW V12 engine consisting of 6.1 litres: the McLaren F1. But despite the obvious similarities – which become even more obvious when you realise that both the M8 and F1's V12s share exactly the same bore and stroke, resulting in them both having identical displacements of 6064cc – the cars do not share the same engine.

Subsequently, they don't share the same power output, neither. The M8's V12 sent 550bhp hurtling at the road through 285mm rear tyres, ready to churn the driver's stomach with performance that only existed on the very fastest hypercars around in 1990. Nowadays, there's plenty of cars that produce that kind of horsepower, so it might not sound all that impressive – but when you place that level of thrust in the automotive world of 1990, you have a car that could potentially trade blows with the most prolific and dominant speed demons of the era.

The Porsche 959 had 444bhp; the Ferrari F40 had 471bhp; the fastest car in the world at the time – the 212mph Ruf CTR – also had 471bhp; and the then newly released Lamborghini Diablo had 485bhp. The 550bhp the M8 had was a simply astronomical amount!

While the acceleration statistics were never officially measured, BMW calculated that the top speed would've sat somewhere north of 200mph. Once again, if you place a top speed like that into the 1990 motoring world, you have one of the fastest cars around.

The M8's engine however wasn't just dramatically different to the regular 850i's thanks to the aggrandisement of extra displacement, and a more advanced valvetrain – it had a much larger carbon intake system wedged at the front of the engine to feed huge quantities of air to a carbon manifold. The whole system was so big and bulky, that fitting it under the regular 8-Series' bonnet was something of a headache – part of which was assuaged by fitting the car with a bulged hood.

The beauty of such an intake system gave the M8's V12 torque characteristics that were more intrinsic with turbocharged engines than normally aspirated motors. While the 368lb-ft it produced might not sound overly impressive, 90% of it was available from just 2,000rpm, with the full helping of it being delivered at 5 grand. This, and the 550 horsepower, gave the car a meaty feel that could be enjoyed even more thanks to the way the driver's right foot was connected to that glorious engine.

The throttle pedal was connected to the engine via 12 individual throttle bodies, unlike the regular 8-Series that sent throttle inputs along an electrical wire. Clearly then, the M8 was all about trying to make the 8-Series as much of a driver's car as it possibly could be. But anyone who even pretends to be a car enthusiast knows that to aid the transformation from wanker's car to driver's car, a dieting process must occur. And with the M8, that's exactly what happened.

In 850i guise, the 8-Series weighed in at a portly 3946lbs (1790kg). In order to make it lighter, the rear seats were binned, and the front armchairs were replaced with much lighter and racy buckets. The hypnotic pop-up headlamps from the 8-Series also got thrown away and replaced with a much lighter system, partly to save weight, but also due to packaging restrictions courtesy of the new cooling system. To top it off, the M8 was garnished generously with lashings of carbon fibre. While the weight saving was never specified, all of the dietary efforts would've been worth a substantial amount on the scales.

The 6-speed manual gearbox, differential, and rear brakes were carried over from the regular 850i; however, the front brakes weren't. Instead, 305mm discs, gripped by 4-piston AP Racing Calipers were used up front to ensure it had the stopping power to cope with its performance.

The chassis and suspension was tuned on the demanding curves of the Nurburgring, and the aerodynamics received a slight tweak thanks to a wind tunnel visit. Two side scoops were added in front of each of the rear wheels – one to cool the engine oil, and one to cool the differential oil. And with that, the transformation from GT to hyper-GT was complete!

In 1990, the finished prototype was presented to the BMW board to decide upon its production fate. There it was, ready and raring to become what would've been a front-engined hypercar in its era, and its existence hung in the balance of a decision that wouldn't be fueled by the lust to create something spectacular; by the undying passion of a motoring heart; or by the unquenchable thirst to deliver enthusiasts with a car they'd adore – the decision would be made purely with money-bags in mind. And tragically, the sums just didn't add up for BMW, and they refused to fund the car for production.

Looking at things from BMW's financial perspective, you can't help but see why they refused to give the M8 the green light. Even with a limited run, for the car to be profitable, the price would've had to have been absolutely outrageous! Much more than twice what someone would pay for a Porsche 911 at the time.

You may think that to entertain the possibility of the M8 project being profitable warrants enough of a case against BMW for not making it. And indeed, they could've priced it at a point that would've resulted in it making money. But here's a funny fact about turning a profit that they don't teach you at business school: in order to make money on a car, the car actually has to sell. And given the price the M8 would've had to have been in order for it to be profitable, BMW didn't think anyone would buy it.

But while a business brain came to the conclusion that the M8 was way too much of a financial risk, a business brain would also be able to swing people's perspective in the direction of creating a market for it had it been produced. If we hypothesise that it's currently 1990 and the M8 has just begun rolling off the production line, anyone with any sense about them wouldn't advertise it as something as mundane as a fast 8-Series – they'd sell it as one of the fastest cars on the planet that could directly compete with the monsters in the exclusive 200mph club.

You could say that the 850CSi – a car that was designed by the same team that built the M8 – proved BMW's skepticism and reticence, as it didn't perform overly well commercially. However, by the time that car was released in 1992, the world's period of financial unrest was more perturbed than ever, which may have played a part in the 850CSi's disappointing sales, as only 1510 were sold in its 4 year life.

The argument for whether BMW should've produced the M8 or not will go on long after the echoes of internal combustion have vanished from this earth. And along with that argument, everyone will be publishing their theories regarding one particularly mystifying element of the whole situation.

For some extraordinary reason, not only did BMW not produce the M8, they also kept all knowledge of its existence a secret. The prospect of an M8 was suspected by the motoring public – but BMW responded to any questions regarding the M8 by indirectly denying it existed.

This inevitably caused much speculation through the life of the E31 8-Series, and even after it went out of production. The M8 lived its trapped life as a myth, shrouded in a clandestine veil, hidden from the public's knowledge, kidnapped by its own parents; and for a reason that to this day nobody understands or knows.

It wasn't until July 2010 when BMW showed the M8 to a number of media professionals at one of their private facilities that the myth became a truth. And it took until 2012 for the M8 to get its first – and so far only – public appearance at the Legends of the Autobahn show in Carmel, California.

While the M8 never making production can be described as a tragedy, and the fact it remained a secret for so many years can be too, what is quite miraculous is that it managed to survive for so many years without being destroyed.

Car companies are infamously barbaric when it comes to their failed prototypes, throwing away masterpieces like a baker would throw away a delicious cake left behind at the end of a day's trade. The fact that the one and only M8 ever made managed to escape destruction is something we should all be infinitely grateful for.

Of course, we know the M8 moniker will be in use soon thanks to a brand new top-tier M car that BMW are producing. It'll most probably be delivered with BMW's increasingly ubiquitous S63 4.4L Twin-Turbo V8, developing something north of 600bhp. The original M8 concept however would've been, if released, way more astonishing back in the early 90's than the new M8 is ever likely to be now. But unfortunately, the impact of the original is something that can only be felt retrospectively, like a posthumous honour.

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Written by: Angelo Uccello

Twitter: @AngeloUccello

Tribe: Speed Machines

Facebook: Speed Machines - DriveTribe

Photo credits: bmwblog and

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