BMW 8 Series (E31)
The BMW E31 is the first generation of the BMW 8 Series. It is a grand tourer
built by BMW from 1990 to 1999 powered by either a V8 or V12 engine. While it did supplant the original E24 based 6 Series in 1990, a common misconception is that the 8 Series was developed as a successor. It was actually in an entirely new model class aimed at a different market, with a substantially higher price and performance than the 6 Series.
Development
Development of the 8 Series began in July 1981, with both the final design phase reaching completion and production development starting in 1986. The 8 Series debuted at the Frankfurt Motor Show in early September 1989. The 8 Series was designed to move beyond the market of the original 6 Series. The 8 Series had substantially improved performance, as well as a far higher purchase price.Over 1.5 billion Deutsche Mark was spent on total development. BMW used CAD tools, still unusual at the time, to design the car's all-new body. Combined with wind tunnel testing, the resulting car had a drag coefficient of, a major improvement from the previous BMW M6/635CSi's 0.39.
The 8 Series offered the first V12 engine mated to a 6-speed manual transmission on a road car. It was one of the first vehicles to be fitted with an electronic drive-by-wire throttle. The 8 Series was one of BMW's first cars, together with the Z1, to use a multi-link rear axle.
While CAD modeling allowed the car's unibody to be 3 kg lighter than that of its predecessor, the car was significantly heavier when completed due to the large engine and added luxury items—a source of criticism from those who wanted BMW to concentrate on the driving experience. Some of the car's weight may have been due to its pillar-less "hardtop" body style, which lacked a "B" pillar.
Sales of the 8 Series were affected by the global recession of the early 1990s, the Persian Gulf War, and energy price spikes. As a result, plans for the high performance M8 variant were dropped in 1991.
BMW pulled the 8 Series from the North American market in 1997, having sold only 7,232 cars over a seven-year period. BMW continued production for Europe until 1999. The worldwide production grand total was 31,062. The base price for an entry-level 8 series in the early 1990s started in the US$70,000 range, which is US$ in.
Production models
840Ci
The 840Ci was offered with two different engine packages. The first used the 4.0-liter M60B40 V8 engine having a power output of and was produced from mid-1993 to late 1995. From mid-1995, production phased in the newer 4.4-liter M62B44 V8 engine, which had better fuel economy and more torque, though power output remained unchanged.The 840Ci was available with a 5-speed automatic transmission, though European cars were given the option of a 6-speed manual transmission. The only external features distinguishing the V8 model from the V12 models were the quad round exhausts, which were square in the V12 models. The 840Ci stayed in production until May 1999.
850i
The 850i was the first model of the 8 Series launched in 1990 with the 5.0-liter M70B50 V12 engine having a power output of. It was available with either a 4-speed automatic or a 6-speed manual gearbox.850Ci
There is some confusion over why and when the 850i became the 850Ci. The change happened around the introduction of the 850CSi and it is believed that BMW decided to include the "C" in the model name that denotes 'Coupe', just as two-door 3 Series cars alongside the 8 Series read 323Ci, 328Ci and so on. The confusion started when BMW installed the new M73B54 V12 engine in the car. This was not an immediate changeover, and indeed both the M70 and M73-engined cars rolled off the production lines side by side for about nine months in 1994, both named 850Ci.As the displacement of the M73 increased to 5.4-litres and the compression ratio went up, the power output increased to.
850CSi
As a top-of-the-range variant of the 8 Series, the 850CSi took over from the prototype M8 variant. The 850CSi used the same engine as the 850i, which was tuned so significantly that BMW assigned it a new engine code: S70B56. The modifications included Bosch Motronic 1.7 fuel injection, a capacity increase to and power increase to at 5,300 rpm and of torque at 4,000 rpm. Road & Track recorded a 0-60 mph time for the 850CSi of 5.9 seconds.The 850CSi's modified suspension included, stiffer springs and dampers that reduced the car's ride height. The recirculating ball steering ratio was dropped 15% over the standard E31 setup. The model also sported staggered throwing star wheels. The front and rear bumpers were reshaped for improved aerodynamic performance. Four round stainless steel exhaust tips replaced the square tips found on other models. The 6-speed manual gearbox was the only transmission option. In Europe, all 850CSi's came with four-wheel steering, upgraded and ventilated brakes with floating front discs, rear differential oil cooler, engine oil cooler, two-tone interior, sports seats, and reshaped mirrors. In the United States, the cars instead received "BMW Motorsport" writing on the doorhandles.
Production ended in late 1996 because the S70 engine could not be modified to comply with new emission regulations without substantial re-engineering.
Powertrain and production data
Engines
Transmission
The 840Ci models were equipped with a 5-speed automatic transmission or a 6-speed manual transmission. The 850i/850Ci models each use either a 4-speed automatic transmission or a 6-speed manual transmission, a 5-speed automatic transmission was fitted from mid-1994. The high performance 850CSi model only came with a 6-speed manual transmission.Fuel economy
2017 United States Environmental Protection Agency estimates for cars equipped with automatic transmission.840Ci
- Fuel type: Premium
- Fuel type: Premium
Prototype models
830i
The 830i was a prototype that did not reach production. As the potential entry-level model, the 830i was to use the 3-liter V8 with from the 530i and 730i, known internally as the M60B30. Eighteen cars were produced, thirteen of which had an automatic gearbox fitted. The model was dropped in favour of the 840Ci and almost all of the 18 cars were dismantled; one car is in a BMW museum.850i Cabrio
The 8 Series had been planned from the start with a convertible version in mind. Although the 850i Cabrio was developed to production readiness, it never went into production. At a relatively late date it was decided that this model was unlikely to recover its development cost. A prototype in red resides in the BMW Museum in Munich.M8
The M8 was originally envisioned as a Ferrari competitor equipped with a special version of the S70 engine, with modifications including a displacement increase to 6.1 litres, dual camshafts for each cylinder bank, individual throttle bodies with roller valves, four valves per cylinder head, carbon fibre intake manifolds and continuously variable valve timing. As a result it was estimated the M8 would achieve a top speed of 198mph. A common misconception is that this engine powered the McLaren F1. The S70/2 used in the McLaren F1 was not based directly on the prototype 4-valve V12 used in the M8, and was a completely new design.The car was given two intakes by its rear arches for engine and differential oil cooling. It was also given a wider track via a wider drive axle as well as uprated front brakes. The interior was completely stripped, with bucket seats and additional gauges for oil pressure, oil temperature, and water temperature. The M8 was given a B-pillar to retain structural rigidity as well as the pop up headlights being deleted from the car.
Other modifications include bodywork modifications such as a new front bumper, new wing mirrors, more flared wheel arches and a vent in the bonnet. The car's kerb weight was reduced to less than 1450 kilograms by making elements of the car glass reinforced plastic, using carbon fibre wheels and removing the rear seats from the car. The windows were made of Lexan.
The project was eventually scrapped because BMW decided that there was no market for a high performance variant of the 8 Series primarily because of the on-going economic recession of the 1990s. The only prototype ever produced was locked away by BMW in the company's Giftschrank. BMW and the M Division had strongly denied that the car was even a possibility since the initial stages of its development. A world exclusive feature in the February 2010 issue of BMW Car Magazine, however, revealed that the M8 prototype still exists in its entirety. The car was unveiled to journalists for the first time on July 2, 2010 at the BMW Museum in Munich. The only public showing of the car happened on August 17, 2012 during 'The Legends of the Autobahn' car show held in Carmel, California. The car was specially shipped from Germany for the appearance.
Although the M8 was never produced, the 850CSi was also tuned by BMW's M division. Aside from sporting an M-tuned engine, the car's VIN identifies the car as being built by BMW Motorsport instead of BMW AG. Per BMW's own protocol, the 850CSi as marketed was essentially a de-tuned version of the putative M8.