The BMW M8 E31 Prototype

The first BMW M8 caused a sensation when it launched a new era of high performance M automobiles in 2019. What is less well known is that around 30 years ago, a model was already in development that bore the same name. In the early 1990s, BMW’s engineers created an M8 prototype based on the then E31 8 Series Coupé – all top secret, of course. However, the very first M8 remained under wraps for almost two decades, and it wasn’t until 2010 that this superlative sports car was finally revealed. Its fate never brought it to the streets as a production model, but the unique prototype would certainly have made waves around the globe had it been released. Here is its fascinating story.

5 POWERFUL FACTS:

M Version based on the 8-Series Coupé E31
6.0 litre V12 engine
Max. output: 640 hp
Max. torque: 650 Nm
M specific exterior and interior

POWERFUL GIANT: THE ENGINE.

The V12 engine of the BMW M8 E31 Prototype

The outstanding feature of the BMW M8 E31 prototype is its large 6-litre engine. V12 engines have always been amongst the most desired by true car enthusiasts, but this one is a particularly unique. The power unit, derived specifically from the S70 engine that was known for top performance, combines superiority, smooth running and enormous performance potential with an impressive appearance. Among the numerous technical highlights, the highly visible intake system, made entirely of carbon fibre, and the roller valves used instead of classic throttle valves, stand out. In addition to the weight advantage, the components allow an unimpeded flow at full load. Top performance was highest priority during development: the M version of the E31 coupe would have rolled onto the road at the beginning of the 1990s with up to 640 hp – a figure almost without competition back then. To put that in context: the most powerful BMW 8 Series at the time was the BMW 850CSi, which produced 380 hp.

CAPABLE OF OVER 300 KM/H.

In conjunction with the manual 6-speed manual transmission, the BMW M8 prototype sprints to 100 km/h in very short time. Official measurements were never carried out, but the BMW 850CSi from 1992 can again be used for comparison: it reached this mark in less than 6.0 seconds.

Added to that is the fact that the M8 prototype only stops accelerating at over 300 km/h – something that would have also been considered astonishing at the time. Even by today's standards, the figures still put this grand tourer in the premier league.

THE EXTERIOR: COMMITTED TO HIGH PERFORMANCE.

The striking bright red paint scheme aside, the BMW M8 prototype presents itself in a slightly more reserved manner, given what lies beneath its progressive bodywork. Yet several exterior features make it stand out from the normal 8-Series E31, underlining the M specific character of this refined racer. Immediately striking are the aerodynamically shaped racing wing mirrors and the widely flared wheel arches. The latter are reminiscent of the legendary first-generation BMW M3 and are further accentuated by the large air intakes in the side panels in front of the rear wheels. The prototype’s wider drive axle creates space for a significantly wider track that, in addition to giving it a bolder stance, also benefits the vehicle’s driving dynamics.

SPORTY YET REFINED GRAND TOURER.

Der hellrote BMW M8 E31 Prototyp und ein neuer BMW M8 F92

The M8 prototype also sets itself apart from the standard BMW 8-Series at the front – or more precisely on the bonnet – where it does without the folding headlights found on all other E31 models at the time. Instead, the dipped and main beam lights are completely integrated into the bumper. This design feature means the one-piece bonnet eliminates any additional gaps that could create additional air resistance, resulting in significantly better aerodynamics, particularly at high speeds. On the other hand, the many lightweight components of the body are barely visible. For example, the doors, boot lid and bonnet are constructed from lightweight glass reinforced plastic. The result is impressive, enabling the high-performance coupé to weigh less than 1,450 kilograms.

THE INTERIOR: MOTORSPORT FLAIR WITH FINE ACCENTS.

The interior trim was given an appropriate level of sportiness that matched the car’s high performance characteristics. The tightly-cut bucket seats provide uncompromising lateral support, while the motorsport-style Sabelt seat belts set a colourful contrast. There is also a short gear lever for quick gear changes and additional instruments in the centre of the dashboard, which is angled towards the driver. The generous use of Alcantara ranges from the door panels across the entire dashboard and onto the centre console.

Inside BMW Group Classic - the elusive BMW M8 (E31) prototype.

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BMW M8 – COMBINING LUXURY AND MOTORSPORT.

It‘s the luxurious elegance combined with genuine M performance that links the E31 BMW M8 prototype with its rightful heir, the BMW M8 F92 from 2019. Both share avant-garde aesthetics and the unrivalled combination of luxury feeling with motorsport performance. The BMW M8 replaces the almost archaic V12 with an ultra-modern BMW M TwinPower Turbo 8-cylinder petrol engine with 460 kW (625 hp). However, the most important feature the two cars share has remained: the BMW M8 receives BMW M’s most powerful engine – but this time it is going into series production.

BMW M8 E31 PROTOTYPE TECHNICAL DATA:

Basics

Development designation: E31
Chassis number: 031EG1100LH231590
Year of construction: 1992
Colour Exterior: Bright Red
Colour Interior: Special upholstery
Construction period: No series production
Units produced: 1

Enginge

Engine type / installation location: V12 Front engine longitudinal installation (S70/2)
Intake: Naturally aspirated engine
Torque: 650 Nm at 5,600 rpm
Power: 640 hp at 7,500 rpm
Displacement: 6,064 ccm
Bore/stroke: 86 mm/87 mm
Compression: 11.0:1

Drive

Transmission type: 6-speed manual transmission
Gear ratio: 4.25/ 2.53/ 1.68/ 1.26/ 1.00/ 0.83:1

Electrics

Generator: three-phase current 140A, 1960W
Battery: 12V 72Ah

Body

Lightweight bodywork / side walls Doors and flaps made of GFK

Chassis

Front suspension: Double wishbone suspension, McPherson struts, coil springs, reinforced torsion bar stabiliser, Electronic Damper Control (EDC)
Rear suspension: Precision control arm axle, suspension struts, coil springs, torsion bar stabiliser, Electronic Damper Control (EDC)
Brakes Front: 1-piston fist-type caliper disc brake, internally ventilated
Front brake diameter: 345 mm
Rear brakes rear: 1-piston, ventilated, 1-piston, fist-type caliper disc brake
Rear brake diameter: 328 mm
Rims front/rear: 8J x 17/9J x 17
Tyres front/rear: 235/45 ZR17 285/40 ZR 17

Dimensions

Length/width/height: 4,780 mm / 1,855 mm / 1,330 mm
Wheelbase: 2,684 mm
Track width front/rear: 1,554 mm / 1,562 mm
Curb weight: 1,443 kg

BMW M8 Competition Coupé [1] :

Fuel consumption combined in l/100 km 11.4

CO2 emissions combined in g/km 260

CO2 class G

AHEAD OF ITS TIME.

The BMW M8 E31 prototype.

5 POWERFUL FACTS: