The Evolution of the E31 BMW 8 Series
An overview of the grunge-era halo car
Introduced at the 1989 Frankfurt Motor Show, the original BMW 8 Series remained largely unchanged during its ten-year production run. Internally coded E31, the 8 Series served as the Roundel's flagship, showcasing BMW's idea of the ultimate in personal luxury transport and its answer to the Mercedes-Benz S-Class Coupe.
It was an innovative vehicle, too. The BMW 850i was the first V-12 production vehicle to feature a six-speed manual and drive-by-wire electronic throttle control. The 8 Series also introduced the use of a CAN (Controller Area Network) bus computer network in an automobile, where a series of microcontroller nodes are networked to function without a central host computer—a precursor to OBD or On-Board Diagnostics. And like the E32 7 Series it's loosely based on, it was one of the first cars to feature electronic stability and traction control.
Here's a look at the four flavors of the E31 that were produced over the years, in order of introduction to the U.S.:
1990-1994 850i/850Ci: The M70 Era
Production of the 850i commenced in 1989 for the 1990 model year. It was powered by the M70B50 5.0-liter V-12. First introduced for the 1987 750i, the naturally aspirated engine produced 296 hp and 330 lb-ft of torque. A six-speed manual was standard, with a ZF-sourced four-speed automatic offered as an option.
BMW changed its nomenclature for 1993, adding a C to designate that the model was a coupe. As a result, the 850i became the 850Ci. 1993 was also the only year when the U.S.-spec variants of the 850Ci were offered with the manual.
The M70-powered 850 was the most popular variant of the E31, with 20,072 produced between 1989 and 1994 (2/3 of the E31's total run of 30,621 cars, including 18 830i prototypes). 4,194 of these cars—about 21% of the total—made it to North America, according to 8coupe.com.
1994-1997 840Ci: The V-8-powered Eight
BMW introduced the 840Ci in 1993 and launched it in the U.S. for the 1994 model year. Initially, power came from the 4.0-liter version of the new-for-1992 M60 V-8, the automaker's first eight-cylinder since 1965 and its second ever. This M60B40 engine was good for 282 hp and 295 lb-ft of torque, giving up little ground to the M70 V-12. A five-speed automatic was the only transmission offered in the U.S., while European models were offered with a manual.
The M60B40 made way for the M62B44 in 1995 for the 1996 model year. The new 4.4-liter V-8 engine made the same 292 hp as the mill it replaced, though torque increased slightly, to 310 lb-ft.
BMW built 4,728 M60-powered 840s and 3,075 M62-powered examples for a total of 7,803 V-8-powered E31s. 2,450 of these made their way to North America—1,649 cars with the 4.0-liter engine and 801 cars with the newer 4.4-liter V-8.
1994-1995 850CSi: Almost an M8
Introduced to the world in 1992, The 850CSi was the flagship of the flagship. Although not marketed and labeled as an official BMW Motorsport product and as an "M8," it was the closest thing to one (one-off prototype notwithstanding).
BMW Motorsport bored and stroked the 850's V-12 to 5.6-liters, and fitted its variant, code-named S70B56, with a forged crankshaft, lighter pistons, more aggressive camshaft profiles, and a freer flowing exhaust and intake. The result was a total of 375 horsepower and 420 pound-feet of torque.
A six-speed manual was the only transmission offered. European models received active hydraulic four-wheel steering for its introductory year, called AHK or Aktive Hinterachskinematik (Active Rear Axle Kinematics), the presence of which is one way to separate U.S.-market originals from grey-market imports.
1,510 850CSis were made in all, with only 225 imported to North America during its two years on the market, with production ending entirely in 1996. The desirable engine and limited run means these command the highest values on the second-hand market.
1995-1997 850Ci: The M73 Arrives
A name change in 1993 has served as the source of some confusion, with some believing that the arrival of the 850Ci coincided with the arrival of the 5.4-liter M73B54 V-12. In reality, the 1993 and 1994 850Ci retained the original 5.0-liter engine.
The M73 arrived in 1994 for the 1995 model year, at least in the U.S., packing 322 hp and 360 lb-ft of torque. With it arrived a new five-speed automatic—but what didn't arrive was an increase in sales. A mere 1,218 M73-powered E31s were produced, with just 363 making their way to North America. As was the case with the 840i, North American sales stopped after the 1997 model year.
If you're in the market…
It's fairly easy to find an 840Ci or 850i/Ci on the used market, but the relatively affordable cost of entry doesn't speak at all for the running costs. The 8 Series is a premium luxury grand tourer and its market positioning is reflected in the price you'll pay to keep it on the road.
Be particularly wary of neglected models as repairs can add up very quickly, especially given that the earliest cars are starting to push 30. Fortunately, the 8 Series community is quite active, so parts are readily available, as is information about maintenance and repair needs.