BMW M8 E31

The BMW M8 E31 is a rare, high-performance prototype based on the BMW 8 Series E31, BMW’s flagship grand tourer from the 1990s. While the production version of the E31 8 Series never received an official M model, the M8 prototype was created as a one-off, with the intention of building a high-performance supercar to rival Ferrari and Lamborghini. However, the project never made it to full production, and the M8 remained a secret within BMW for many years, only coming to public attention in the early 2000s.

1. Background and Legacy

• Production years: The E31 8 Series was produced between 1989 and 1999, but the M8 prototype was developed in the early 1990s.
• Body style: 2-door grand tourer/coupe.
• Purpose: BMW M's engineers wanted to create a high-performance variant of the E31 to demonstrate BMW’s engineering capabilities and create a halo car for the brand. The M8 was designed to compete with the likes of the Ferrari Testarossa and Lamborghini Diablo.
• Cancellation: Due to several factors, including high development costs, market changes, and economic downturns in the early '90s, BMW decided not to proceed with mass production of the M8. The project was kept secret until the prototype was revealed to the public much later.

2. Engine and Performance

The heart of the BMW M8 E31 was a highly modified version of BMW’s S70 engine, which was a naturally aspirated V12. This engine is one of the most important aspects of the M8’s mystique, as it was a high-performance version of the engine that also served as the basis for the BMW-powered McLaren F1.

• Engine: 6.1-liter S70/1 V12, naturally aspirated.
• Power output: Estimated around 550–640 horsepower (exact figures vary, as BMW has never officially confirmed the exact numbers for the prototype).
• Torque: Unknown, but likely well above 450 lb-ft.
• Transmission: 6-speed manual transmission.
• 0-60 mph: Likely around 3.8–4.0 seconds based on the power and configuration.
• Top speed: Estimated to be around 200 mph (322 km/h), though it was never officially tested or confirmed for public records.

The engine was derived from the M70 V12 that was used in the 850i and 850CSi, but the M8’s version was heavily reworked with larger displacement, improved internal components, and a more aggressive tune, making it one of the most powerful naturally aspirated engines of its time.

3. Chassis and Handling

To handle the immense power of the V12 engine, the M8 prototype featured several upgrades over the standard 8 Series models. BMW M engineers worked on making the car lighter, stiffer, and more responsive.

• Weight reduction: The M8 prototype used lightweight materials, including carbon fiber for certain components, to reduce weight significantly compared to the standard 8 Series. BMW reportedly aimed for a weight of around 1,500–1,600 kg (around 3,300–3,500 lbs), which would be very light for a V12 grand tourer of that era.
• Suspension: The suspension was completely overhauled to deliver better handling and cornering ability. It likely featured a double-wishbone front suspension and multi-link rear suspension, with tuning specifically for the M8’s performance characteristics.
• Brakes: The M8 would have been equipped with larger high-performance brakes, likely vented disc brakes, to manage the car’s power and speed.
• Aerodynamics: The M8 featured a more aggressive aerodynamic body kit than the standard 8 Series, with additional air intakes and a reworked rear diffuser to help with cooling and downforce.

4. Design and Styling

The M8 prototype was visually more aggressive and performance-focused compared to the standard E31 8 Series models. While it retained the sleek and futuristic shape of the 8 Series, it had several key differences to reflect its supercar status.

• Wide body: The M8 had wider fenders and a more muscular stance to accommodate wider track widths and larger wheels.
• Hood design: One of the most notable features of the M8 was its distinct vented hood, which had large air ducts to help cool the V12 engine. This feature alone set it apart from the standard 8 Series.
• Aerodynamic enhancements: The front bumper had larger air intakes, and the rear had a more pronounced diffuser to improve airflow and stability at high speeds.
• Wheels: The M8 prototype had unique lightweight alloy wheels and performance tires designed for high-speed stability and grip.
• Minimalist interior: While few details of the interior are publicly known, it's reported that the M8 prototype had a minimalist racing-inspired interior, with lightweight materials and fewer luxury features to keep the car focused on performance.

The overall look of the M8 was a perfect blend of elegance and aggression, staying true to the E31’s sleek grand tourer profile while giving it an unmistakable supercar presence.

5. Technology and Features

While the M8 prototype was designed primarily for performance, it still retained some of the advanced technology that BMW was known for at the time.

• Electronic aids: The M8 likely featured advanced driver aids for the time, such as an early form of traction control and ABS, to help manage the immense power being sent to the rear wheels.
• Advanced electronics: The E31 8 Series was known for its cutting-edge electronics in the 1990s, including a complex multi-function control system, which the M8 would have retained in a more performance-focused configuration.
• Weight-saving measures: To keep weight down, luxury features like power-adjustable seats, excessive insulation, and other comfort options were either minimized or removed completely.

6. Why the M8 Project Was Canceled

Despite its incredible potential, BMW decided to cancel the M8 project before it went into production. Several reasons contributed to this decision:

• Market conditions: In the early 1990s, the global economy, particularly in Europe, was struggling, and demand for ultra-expensive supercars was uncertain. BMW was unsure if there would be enough buyers for such an expensive and specialized model.
• Cost: The M8 would have been extremely costly to develop and produce, especially given its use of advanced materials and technology for the time.
• Focus on other models: BMW chose to focus its resources on other important projects, including its bread-and-butter models like the 3 Series and 5 Series, which had more significant impact on the brand’s overall sales and profitability.

7. Legacy and Impact

Though the BMW M8 E31 never reached production, its legacy lived on in several key ways:

• 850CSi: While not a full M car, the BMW 850CSi was the closest thing to a production M8. It featured a detuned version of the S70 engine, producing 375 horsepower and enhanced handling dynamics. The 850CSi was essentially the top-tier version of the E31 lineup and a tribute to the M8’s potential.
• Inspiration for the modern M8: Fast forward to 2019, BMW finally released an official M8 based on the modern G15 8 Series. The modern BMW M8 (F91/F92/F93) delivers on the supercar potential that the original M8 prototype hinted at, with 600+ horsepower from a twin-turbo V8, modern technology, and cutting-edge performance.

8. Revelation of the M8 Prototype

For many years, the M8 prototype remained a closely guarded secret at BMW. It wasn’t until 2010 that BMW officially revealed the existence of the M8 prototype to the public during a special media event. The car was stored in BMW’s "secret garage" at their headquarters in Munich. Today, the M8 prototype remains a one-of-a-kind piece of BMW’s history, a reminder of the company's bold vision to create a true supercar in the early 1990s.