BMW M8 (E31) by Erremm, Wikimedia Commons, CC BY-SA 4.0. (credit link at the end of the content)
We continue our journey of bringing forgotten classics back to life. As you all know, we are mainly focused on F1 stories, especially forgotten F1 teams and unrealized projects, but we also want to explore classic cars that never made it into production, like the incredible BMW E31 M8 prototype.
In the history of BMW, few cars have achieved the mythical statys of the E31 M8.
It wasn’t simply a faster version of the 8 series, BMW created the M8 as an ambitious, secret project designed to turn the elegant E31 into a genuine Ferrari challenger.
The result was extraordinary, with 6.0-liter V12 engine, connected to a six-speed manual gearbox, while extensive weight-saving measures transformed the luxurious grand tourer into something much more serious, and yet, BMW never sold it!
Only one functional BMW E31 M8 prototype was completed, and after years hidden away from public, the mysterious red machine eventually became one of the most fascinating ‘what if’ cars in BMW history.
The BMW E31 M8 Was Already an Ambitious Project
When BMW introduced the E31 8 Series at the end of the 80s, it was intended to sit at the top of the company’s range, the car combined advanced tech, sophisticated styling and powerful V8 and V12 engines in an attempt to create a modern luxury grand tourer, but BMW motorsport had something more extreme in mind!
The standard 8 Series was heavy and luxurious, the M8 project took a very different approach, engineers wanted to remove unnecessary weight and extract substantially more performance from the E31 platform.
The idea was simple, if BMW was going to challenge Ferrari, the car couldn’t merely be a comfortable high-speed cruiser, it needed to behave like a supercar, that philosophy produced the secret BMW E31 M8.
What are the specs of the BMW E31 M8 prototype?
The heart of the M8 was its engine, BMW developed a special 6.0-liter naturally aspirated V12 known as the S70, while the exact output figures associated with the prototype vary between historical sources, estimates have placed its power at around 640 horsepower, with approximately 650 Nm of torque, those numbers were astonishing for the early 1990s.
The engine was substantially more aggressive than the V12 used in the regular 8 Series, engineers worked on increasing displacement and improving the engine’s ability to breathe at high engine speeds, creating a powerplant intended for serious performance rather than relaxed grand touring.
It was paired with a six-speed manual transmission, giving the M8 something that the increasingly sophisticated luxury cars of the period often lacked, direct involvement between driver and machine.
The significance of the engine would become even clearer later, the S70 development work became part of the technical foundation for the legendary McLaren F1’s V12, that connection helped turn the forgotten BMW prototype into an important chapter in the story of one of the world’s most celebrated supercars!
BMW Stripped Away the Luxury
The biggest problem with turning an 8 Series into a Ferrari rival was its weight, the engineers therefore tried everything.
The M8 received lightweight body components, including fiberglass and other weight-saving materials, while conventional glass was replaced with lighter alternatives, the famous pop-up headlights of the normal E31 were also abandoned in favor of fixed units.
Inside, the emphasis was similarly different, the M8 wasn’t meant to be a luxurious long-distance car, it was designed around performance, every kilogram mattered.
This made the BMW E31 M8 fundamentally different from the production 850i, the regular car represented BMW’s vision of a high-tech luxury GT, while the M8 was much closer to an experimental supercar wearing the shape of an 8 series!
How Many BMW E31 M8 Prototypes Were Built?
This is where the M8 story becomes especially fascinating, BMW built exactly one functional E31 M8 prototype.
It was finished in bright red and remained hidden from the public for years, BMW didn’t put it into a showroom, offer it to customers or produced a limited run for wealthy collectors, there was only one!
That makes the E31 M8 fundamentally different from many other famous BMW M cars, it wasn’t an unsuccesful production model, it never became a production model at all.
The prototype became a rolling engineering experiment, allowing BMW to explore what the E31 platform could achieve if there was virtually no compromises!
So Why Did BMW Cancel E31 M8 prototype?
The E31 M8 proejct was ultimately abandoned in 1991, and the timing could hardly have been worse for an expensive new supercar, the early 1990s brought a serious economic downturn, energy-price instability added further uncertainty to the global economy.
BMW was also facing a problem much closer to home, the standard 8 Series wasn’t selling as strongly as the company had hoped!
That made the business case for an even more expensive, highly specialized version extremely difficult to justify, BMW could have spent enormous amounts of money developing the M8 for production, only to discover that there were not enough customers willing to pay supercar money for it, a spectacular prototype could be built inside BMW’s engineering department.
A production supercar required something else entirely, a convincing financial case, and BMW didn’t have one!
How Much Did the M8 Cost to Build?
There is an important distinction between the cost of building the prototype and the cost of developing an eventual production version.
Reports suggest, the E31 M8 program itself was enormously expensive, BMW reportedly invested close to $1 billion in developing the 8 Series platform during the late 1980s.
Even ordinary experimental E31 prototypes could cost extraordinary amounts because components had to be individually manufactured and assembled for testing, the M8 was even more specialized.
With unique V12, extensive lightweight, modified bodywork… cost of constructing the individual prototype around or above the million-dollar level are plausible, but they should be treated as estimates rather than an official BMW figure.
The real expense would have come if BMW had decided to put the M8 into production, that would have required further engineering, testing emissions certification, manufacturing tooling and a production system capable of building an extremely low-volume supercar!
What Would the BMW E31 M8 Have Cost?
The estimated price makes the decision to cancel the car easier to understand, had the M8 reached production around 1991, reports suggest that estimates have placed its potential price at approximately 250,000 German Marks, equivalent to roughly $180,000 at the time.
That would have positioned it far above the regular 8 Series and into serious supercar territory, BMW would have been asking customers to spend roughly twice the price of a contemporary Porsche 911 turbo, depending on market and specification.
That was a difficult proposition during an economic downturn, the M8 may have had the performance to justify the price, but BMW still had to convince customers that they wanted a Ferrari-rivaling supercar from a company whose flagship 8 Series was primarily known as a sophisticated luxury GT!
Similar story: If you are interested in more stories like the BMW E31 M8 Prototype, we recently covered another fascinating prototype that never made it into production, the Nissan MID4.
The 850CSi Became the Closest Reality
Although the M8 disappeared, BMW didn’t completely abandon the idea of creating a more powerful E31, the eventual 850CSi became the closest production relative to the M8 concept.
It received a heavily modified of BMW’s V12 and significant performance upgrades, giving customers a much more sporting alternative to the regular 8 series.
But it wasn’t the M8, the 850CSi remained a sophisticated grand tourer rather than the stripped down, ultra-high-performance machine BMW’s engineers had imagines, in other words, the M8 showed what BMW could build when there were almost no limits, the 850CSi showed what BMW was actually prepared to sell.
Similar story: If you are interested in more stories like the BMW E31 M8 Prototype, check out our article about the Aston Martin Bulldog, another fascinating prototype that never made it into production.
The BMW M8 That Never Was
The E31 M8 remains one of BMW’s greatest automotive ‘what ifs’, it had the engine, the technology and the ambition to challenge the world’s leading supercars, it was lighter, more powerful and more focused the the production 8 Series, and its specially developed V12 eventually played a role in the story of the McLaren F1.
Note: The M8’s S70/1 V12 didn’t directly become the McLaren F1 engine, but it laid important groundwork for it. BMW’s Paul Rosche later developed the clean-sheet S70/2 V12 for the McLaren F1, building on the engineering experience gained from the M8 project.
However, BMW created the M8 at a moment when the global economy was turning against expensive performance cars, while the standard 8 Series itself was struggling to establish the commercial success BMW wanted, so the company made a decision that probably made perfect business sense at the time, the M8 project was cancelled, only one was build.
Today, that decision is precisely what makes the E31 M8 so fascinating, BMW didn’t fail to build the car because its engineers couldn’t make it work, they built it, proved what it could do, and then decided that the world wasn’t ready to buy it.
More three decades later, the red prototype stands as a reminder of just how far BMW’s engineers were willing to go when they imagined the ultimate version of the E31.
The world eventually got the 850CSi, but the M8 remained the supercar BMW built in secret, and then chose never to sell!
Featured Image Credits: BMW M8 (E31) by Erremm, Wikimedia Commons, CC BY-SA 4.0.
