BMW 8 Series

BMW 8 Series (E31)
Overview
Manufacturer	BMW
Production	1989–1999 31,062 built
Assembly	Germany
Designer	Klaus Kapitza (1986)
Body and chassis
Class	Grand tourer
Body style	2-door coupé
Layout	FR layout
Powertrain
Engine	4.0 L M60 V8 4.4 L M62 V8 5.0L M70 V12 5.4 L M73 V12 5.6L S70 V12
Transmission	4-speed automatic 5-speed automatic 6-speed manual
Dimensions
Wheelbase	2,685 mm (105.7 in)
Length	4,780 mm (188 in)
Width	1,854 mm (73.0 in)
Height	1,341 mm (52.8 in)
Curb weight	1,830 kg (4,030 lb) (840) 1,975 kg (4,354 lb) (850)

The BMW 8 Series (chassis code: E31) is a Grand Tourer built by BMW from 1989 to 1999 powered by either a V8 or V12 engine. 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). However, de-limited the manual 850 will do 190 mph (305kmph)

History of development

BMW E31 rear styling

Design of the 8 Series began in 1984, with the final design phase and production development (starting) in 1986. The 8 Series debuted at the Frankfurt Motor Show (IAA) in early September 1989. The 8 Series was designed to move beyond the market of the original 6 Series. The 8 Series however had substantially improved performance, as well as a far higher purchase price.

Over 1.5 billion Deutschemark was spent on total development (2008 USD nearly $1 billion). 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 0.29, a major improvement from the previous BMW M6/635CSi's 0.39.

The 8 Series supercar offered the first V-12 engine mated to a 6-speed manual gearbox on a road car. It was the first car to feature CAN bus - a form of multiplex wiring for cars which is now an industry standard. It was also 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 8 lb (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 pillarless "hardtop" body style, which lacked a "B" post. This body style, originating in the United States in the late 1940s, was abandoned by Detroit in the late 1970s.

Sales of the 8 Series were affected by the global recession of the early 1990s, the Persian Gulf War, and energy price spikes. BMW pulled the 8 Series from the North American market in 1997, having sold only 7,232 cars over seven years. BMW continued production for Europe until 1999. The ultimate worldwide production total was 31,062. The base price for an entry-level 8 series in the early 1990s started in the $70,000 range which is $126,788 in 2021.

Production models

840Ci

BMW 840Ci M62 V8 engine

The 840Ci exists with two different engine packages. The first used the 4 litre 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 litre 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.

850i

BMW 850i/Ci M70 V12 engine

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.

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 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).

850CSi

BMW 850CSi S70 V12 engine

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 which reduced the car's ride height. The recirculating ball steering ratio was dropped 15% over the stock 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), Floating front brake discs, rear differential oil cooler, engine oil cooler and sports seats.

Production ended in late 1996 because the S70 engine could not be modified to comply with new emission regulations without substantial re-engineering.

Prototype models

830i

The 830i was a prototype which did not reach production. As the potential entry-level model, the 830i was to use the 3-liter V8 with 218 PS (160 kW; 215 hp) from the 530i and 730i, known internally as the M60B30. Eighteen cars were produced, 13 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

850i Cabrio Prototype, as seen in the BMW Museum in August 2015.

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

Originally envisioned as a Ferrari competitor equipped with a special 550 bhp (410 kW; 558 PS) version of the S70 engine, essentially a bored out version of the M70 with experimental multi-valve cylinder heads. A common misconception is that this engine powered the McLaren F1. However, when this was suggested to McLaren's designer Gordon Murray, the idea was rejected because the engine was too heavy and long for the McLaren F1. Rather, variations on the original S70 used on the 850csi, the S70/2 and S70/3 were used for the McLaren F1 (The variation used on the M8 prototype was the S70/1 engine).

The project was eventually scrapped because BMW decided that there was no market for an M8. The only prototype ever produced (one that was reportedly not even road safe) was locked away by BMW in the company's Giftschrank (poison storage) . 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.

While the M8 was never produced, it is interesting to note that the 850CSi was also tuned by BMW's M division. Aside from sporting an M-tuned engine (as identified by the S prefix instead of the M prefix that a non-M tuned engine would bear), 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.

Motorsport

The 8-Series is a very rare car to see in any form of motorsport. However, one of the most successful examples was built by Wagenstetter Motorsport and, until recently, was raced in the Nurburgring VLN endurance championship. It’s based on an 840i, but now has an E39 M5 5.0-litre V8, which has 555 bhp (414 kW; 563 PS) and 472 lb⋅ft (640 N⋅m) torque, and a six-speed gearbox from the same car.

Powertrain and production data

Model	Years	Engine code	Power	Torque	Production total
840Ci	1992–96	M60B40	210 kW (286 PS; 282 hp)	400 N⋅m (300 lb⋅ft)	4,728
840Ci	1995–99	M62B44	210 kW (286 PS; 282 hp)	420 N⋅m (310 lb⋅ft)	3,075
850i	1989–94	M70B50	220 kW (299 PS; 295 hp)	450 N⋅m (330 lb⋅ft)	20,072
850Ci	1992–99	M73B54	240 kW (326 PS; 322 hp)	490 N⋅m (360 lb⋅ft)	1,218
850CSi	1992–96	S70B56	280 kW (381 PS; 375 hp)	550 N⋅m (410 lb⋅ft)	1,510

Transmission

BMW 840Ci transmission selector

The 840Ci (4.0/4.4l V8) models were equipped with a 5-speed automatic transmission or a 6-speed manual transmission. The 850i/850Ci (V12) models each carry either a 4-speed automatic transmission or a 6-speed manual transmission,a 5-speed automatic transmission was fitted from mid-1994. The 850CSi model only came with a 6-speed manual transmission.

Fuel economy

1997 United States Environmental Protection Agency estimates for cars equipped with automatic transmission.

840Ci

• Fuel type: Premium

city: 15 miles per US gallon (16 L/100 km; 18 mpg_‑imp)

highway: 20 miles per US gallon (12 L/100 km; 24 mpg_‑imp)

combined: 17 miles per US gallon (14 L/100 km; 20 mpg_‑imp)

850Ci

• Fuel type: Premium

city: 14 miles per US gallon (17 L/100 km; 17 mpg_‑imp)

highway: 20 miles per US gallon (12 L/100 km; 24 mpg_‑imp)

combined: 16 miles per US gallon (15 L/100 km; 19 mpg_‑imp)

For the 850i, 1991 Sport Model specifically the On-Board computer will typically read 24.6L/100 km when the car is often used under heavy acceleration. These figures could be similar if not slightly less/more for more newer versions of the 850i Sport.

Similar automobiles

• Porsche 928
• Mercedes-Benz SL73 AMG
• Jaguar XJR

External links

• Clube31
• BMW Club E31 NL
• 8er.org
• E31.net
• Pictures of BMW M8