BMW 8 Series (E31)

840Ci

The 840Ci was offered with two different engines. The first used the 4.0-litre M60B40 V8 engine having a power output of 210 kW and was produced from mid-1993 to late 1995. From mid-1995, production phased in the newer 4.4-litre 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/Ci

The 850i was the first model of the 8 Series launched in 1990 with the 5.0-litre M70B50 V12 engine having a power output of 220 kW.[13] It was available with either a 4-speed automatic or a 6-speed manual gearbox.

Around the time of the introduction of the 840Ci in Autumn 1993, the 850i was renamed the 850Ci. From October 1994, BMW installed the new M73B54 V12 engine in the 850Ci, the new engine being from the newly launched E38 750i. Thus, cars with 850Ci badging used both the M70 and M73 engines, with those built before 10/94 using the older E32-type M70. As the displacement of the M73 increased to 5.4-litres and the compression ratio went up, the power output increased to 240 kW.

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 5576 cc and power increase to 280 kW at 5,300 rpm[14] and 550 Nm of torque at 4,000 rpm.[15] Road & Track recorded a 0 - 60 mph time for the 850CSi of 5.9 seconds.[16]

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 (AHK - Aktive Hinterachs-Kinematik, Active rear axle Kinematics), 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.

830i

The 830i was a prototype that did not reach production.[19][20] As the potential entry-level model, the 830i was to use the 3-litre V8 with 160 kW from the 530i and 730i, known internally as the M60B30. Eighteen cars were produced, thirteen of which had an automatic gearbox fitted.[21] 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 the cost of putting it into production. A prototype in red resides in the BMW Museum in Munich. Although an official convertible variant never entered production, there have been aftermarket companies who have converted small numbers of 8 Series coupés into convertibles.[10]

M8

The M8 was originally envisioned as a Ferrari competitor equipped with a special version of the S70 V12 engine, with modifications including a displacement increase to 6064 cc, dual overhead camshafts for each cylinder bank, individual throttle bodies with roller valves, four valves per cylinder, carbon fibre intake manifolds and continuously variable valve timing. As a result, it was estimated the M8 would achieve a top speed of 320 km/h, with a power output of 640 PS and 650 Nm of torque.[22][23] A common misconception is that this is the same engine that powered the McLaren F1. The S70/2 used in the McLaren F1 was not based on the prototype 48-valve V12 used in the M8, and was a completely new design.[24][25]

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 having its pop up headlights 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 kg by making elements of the car glass reinforced plastic (such as the bonnet, doors and boot lid), using carbon fibre wheels and removing the rear seats from the car. The windows were made of Lexan. The oil reservoir was moved to the trunk of the car; oil pipes went through the roof of the car.

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 (one that was reportedly not even safe for normal road usage) was locked away by BMW in the company's Giftschrank (poison storage).[26] 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.[27] The car was unveiled to journalists for the first time on July 2, 2010, at the BMW Museum in Munich.[28] The only public showing of the car happened on August 17, 2012, during 'The Legends of the Autobahn' car show held in Carmel, California.[29] 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 (as identified by the S prefix (which a non-M tuned engine would bear) instead of the M prefix), the car's VIN identifies the car as being built by BMW Motorsport (a WBS prefix) instead of BMW AG (WBA prefix). Per BMW's own protocol, the 850CSi as marketed was essentially a de-tuned version of the putative M8.[30]

B12 5.0

The B12 5.0 was built from 1990 to 1994 based on the BMW E31 850i with an Alpina-modified BMW M70 V12 (shared with the E32 B12 5.0) producing 350 hp-metric and mated to an automatic transmission.

B12 5.7

The B12 5.7 was available from 1992, based on the BMW 850CSi with the BMW S70B56 V12 engine bored out to 5.7 litres along with a modified intake, crankshaft, camshafts and a stainless steel exhaust system as well as a 6-speed manual gearbox. The modified engine produced 306 kW. The carbon-fibre bonnet had cooling vents and a NACA duct for improved engine cooling. Performance figures included a 0-60 mph acceleration time of 5.8 seconds and a top speed of 300 km/h.[31]