It’s the early 1990′s, you’re a German executive working for BMW in the incredible 4-Cylinder tower in downtown Munich. Not far from you, a certain, important bright red prototype is sitting, waiting for a decision to be made – a simple yes or no as to if the car will make the leap to a production series car. On the one hand, you’re a car enthusiast, someone who would love to green light a 500+HP grand tourer with a six speed manual, rear-wheel-drive and acres of leather to cover up the inner workings and systems of the most technically advanced road car your company has ever built.

Then there is the business side of you – the side that is more calculated and looks at the business case of such a vehicle and evaluates the pro’s and cons in a cold, harsh light with other variables surrounding this decision. The German economy has been rattled from a recent worldwide recession. The prototype in question, along with the base car on which it was built, has already cost millions upon millions of deutschmarks and the base model series has received a only lukewarm reception from your biggest market, the United States. This despite the model being both in-line with the luxurious and sporting brand image and delivering a suitable blow to fellow German rivals. However, a flagship, expensive sports car with flat sales and rising manufacturing labor costs during a recession?

No – it won’t be built – this car will not make it beyond the prototype stage.

With that, the so called ‘M8’  would be boxed up, waiting to be destroyed.; most definitely out of the public eye. With this decision the most powerful production BMW (until the X5/6 M), was relinquished to a life of ‘Giftschrank’, in a complex with other prototypes and projects that didn’t quite make it to the assembly line.

However, mystery and rumors circulated around the M8 Prototype and whether or not it ever existed. If it did, had BMW disassembled the big 8 like it does so many test mules and prototypes? The only proof available for almost two decades were rumors of output and a handful of grainy photos showing a heavily modified 850i with a revised air dam, aggressive vented hood, and some specialized body ducts to channel air.

Aside from that, publicly there was no evidence that the M8 had existed. As time marched on, many enthusiasts found themselves enthralled by the idea of such a car that never made it to market despite a substantial leap forward in performance of the time. What did make it to market was the ~300hp 840i/850i and the superior 850CSi (380hp and only offered with a 6-speed manual). The 850CSi carried both M-derived engine codes and VIN’s. Aside from sporting an M-tuned engine (as identified by the S suffix instead of the M prefix that a true M car would wear), the car’s VIN identifies it as being built by BMW Motorsport (identified by the WBS prefix) instead of BMW AG (WBA prefix). This effectively identifies the 850CSi as essentially a detuned version of the M8.

The 850CSi had to make do with only 380HP – a mind blowing 170HP less than the rumored 550HP churned out by the M8 Prototype.  Hence, the M8 was a major piece of controversy for BMW enthusiasts around the globe for the next decade and a half. Speculation of what the M8 was and what it could have been capable of grew even more with the inception of the internet and car forums. Many thought it was a fully functional model, many thought it had been destroyed and many thought it was alive and kicking but roughly a shell of an 8 Series with non-functioning headlamps, air conditioning and many onboard systems. After nearly 20 years, BMWBLOG’s founder and head honcho Horatiu, managed to finally see the red devil in the flesh during a press conference a few months ago when BMW nonchalantly displayed the M8 in Munich for a handful of other, more pressing projects of the company. Upon further inspection Horatiu found the M8 to be a working prototype of a car that had managed to live in the shadows of the Munich 4-Cylinder tower and in hearts of so many BMW enthusiasts for decades.

With such an incredible revelation – more information had to be sought out. From what was learned about the M8 Prototype (as the car is officially/unofficially titled– it is not a “concept” but a working mock-up of a car set for production); had this car managed to reach green light status, its sheer performance on every front would have been staggering relative to any competition of the time period.

This is a proper touring coupe with a engine in the front, a manual 6-speed transmission in the middle, and limited slip controlled drive at the rear. A big V12 (larger than 5.0L of the 850i/850CSi) is nestled under the bulging, vented hood. The engine carries with it 12 individual throttle bodies connected to the driver’s right foot via direct cable making the M8 Prototype the first non-drive-by-wire 8 Series and proof of BMW M GmbH’s dedication to providing a tactile driving experience (later 840Ci’s received this also).

Interestingly, one of the biggest misconceptions of the M8 is that it shares an engine with the record shattering McLaren F1. It was around the same time as the development of the M8 that McLaren commissioned BMW and Paul Rosche to build a capable V12 to power their supercar (of course this was after McLaren was denied by Honda). Interestingly from a design standpoint, they shared quite a few design characteristics and parts with the S50 engine of the E36 M3. Fundamentally, it is two Euro S50 engines mated together side by side.

Per our sources, the McLaren V12 (a modified S70) and the M8′s V12 were constructed by many of the same engineers; hence a similar design and output. But the two differed in areas such as overall length, due to the horizontal intakes for a front engine layout as compared to the vertical intakes for the mid-engined McLaren.

At the wedge-shaped nose, which resembles the E26 M1 nose, a revised front fascia allowed for better channeling of air into the massive intakes that feed the engine. Sitting behind the air dam and just forward of the engine is a huge escape air duct; helping to channel air and promote airflow through the radiator and oil cooler setup for cooling. Other revisions at the nose are lightweight headlamps, modified to both reduce weight and replace the standard E31 pop up lamps– which were sacrificed for the greater good of space in the engine bay.The M8 Prototype distances itself further still from fellow 8′s with styling that meshes the sleek coupe lines with purposeful, yet necessary upgrades. Gliding down the flanks of the prototype, the coupe carries the same wide hips of the 850CSi with a widebody kit modified to accommodate better cooling of the brakes. The kit’s also believed to be used to channel air as a means of cooling the rear differential.

Wedged underneath the flared wheel arches are 17 inch M Systems wheels with a carbon fiber overlay (also seen on the one-off Z1 prototype from the ‘Giftschrank’ link above). While we don’t have exact figures, the rear wheels are quite wide to keep the big coupe planted in the twisties. Our sources indicate that the tires are Michelin PilotSports of the period. Notice here the custom multi-piece front brake kit that was fitted.

Weight savings in sports cars is very commonplace these days but in the early 1990′s, only cars like the Ferrari F40 or Porsche 959 used weight savings materials extensively throughout to maximize performance. Specific body panels such as the doors, arches, and ducts are constructed from carbon fiber reinforced-polymer(CFRP) which are lighter than the standard components of the production E31.

Additionally, the Prototype carries lightweight Plexiglas window frames which, per BMW, bear heavily resemblance to the E92 M3 GT’s same window frames. BMW even made the hood, with a large air vent front-and-center of the engine bay out of CFRP. They even went to the trouble of installing specialized headlamps with revised functions to let what would have been standard fog lights act as the primary lighting. The effect of these revised headlamps is two fold: to lighten the lamps as well as provide extra room for the massive air filter boxes sitting just below the hood. Again, the design of the car is focused on performance as priority number one.

The biggest divergence from the production cars is the addition of a B pillar; something noticeably different from the cleaner lines of the original design. The B pillar (along with framed doors) was a necessary addition. It was a means of injecting further rigidity into the big coupe in order to combat the natural trend of a coupe’s body to flex under heavy load.

There a several notable changes to the interior over the production E31’s. The cockpit has a three spoke M Tech II sports steering wheel. BMW went as far as to outfit the entire cabin in suede to keep interior grip levels high. The dash has a unique motorsport cluster with red needles… keeping the style of the E30 M3, which also had red needles in the gauge cluster.

The center console was modified with two VDO-manufactured pressure gauges along with a manual climate adjustments panel added to the dash.

The typical auto dimming mirror was not retained, likely for further weight savings. The headliner was also suede material, just as almost the entire interior as a whole. The custom suede paneling created a unique cockpit feel, nothing like any other E31. Other interior upgrades include heavily bolstered seating to keep occupants in place as well as to reduce weight. From our pictures and onsite reports, BMW also outfitted the interior with heavy-duty set of seat belts/harnesses to further ensure that the driver doesn’t budge one centimeter from the wheel – keeping the sole focus on the driving experience.

With all of these considerations – it’s easy to say the M8 was great super car that unfortunately, was never sold.

The car was trimmed down on par with the E46 M3 CSL, the engine was tuned to a point that it would only find rival equivalents offered by BMW nearly two decades later with the X5/6M’s and F10 M5.

The M8 Prototype is a car that represents BMW Motorpsort at its absolute peak; during the early 1990′s when M GmbH had produced a couple of major successes with the E30 M3 and E28 M5. They had another success in their hands with the M8, but it was to become a victim of timing – a car decades ahead of its time but undeniable in its nature and potential abilities.