The BMW 8 Series (chassis code: E31) is a V8 or V12-engined Grand Tourer built by BMW from 1989 to 1999. While it did supplant the original E24 based 6 Series in 1991, a common misconception is that the 8 Series was developed as a successor. However, it was actually an entirely new class aimed at a different market, with a substantially higher price and better performance than the 6 series. It was BMW's flagship car and had an electronically limited top speed of 155 mph (250 km/h).
The 840Ci exists with two different engine packages. The first used the 4 liter M60B40 engine with 286 PS (210 kW) and was produced from mid-1993 to late 1995. From mid-1995, production phased in the newer 4.4 liter M62B44 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.
This was the first model launched in 1990 with the 5 litre M70B50 V12 engine producing 300 PS (221 kW; 296 hp). It was available with either a 4-speed automatic or a 6-speed manual gearbox.
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 starts when BMW installed the new M73B54 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 capacity of the M73 increased to 5.4 liters and the compression ratio went up, the power output rose to 326 PS (240 kW; 322 hp).
As a top-of-the-range sports tourer, the 850CSi took over from the prototype M8. 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 a capacity increase to 5.6 liters and power increase to 380 PS (279 kW; 375 hp). The 850CSi's modified suspension included stiffer springs and dampers and reduced the car's ride height. The recirculating ball steering ratio was dropped 15% over the stock E31 setup. The model also sported wider wheels, with the option of forged alloys. 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 (AHK - Aktive Hinterachs-Kinematik).
Production ended in late 1996 because the S70 engine could not be modified to comply with new emission regulations without substantial re-engineering.