The E31: the same engine, a different bargain
The 850i’s arrival at Frankfurt in September 1989 made BMW’s ambition visible in a way the sedan could not. The E32 was an expensive variation on a familiar silhouette. The E31 looked like a separate undertaking: low nose, retractable headlights, a broad glass canopy, and a long body that made little attempt to maximize the number of people inside it. BMW had found another use for its engine, and another way to spend the margin around it.
It was a grand tourer rather than an E32 with two doors removed. Its four seats did not confer the sedan’s rear accommodation, and its length did not make it a spacious family car. The body allocated room to the engine, the front occupants, and the long sweep of its profile. The buyer was purchasing a different relationship between distance, comfort, and appearance.
The shape remains compelling because its surfaces have work to do. The nose is low, the glass sits closely within the body, and the rear volume rises enough to make an aerodynamic termination without becoming a separate architectural event. The car looks substantial even when the lamps are down and most of its face has disappeared.
BMW quoted a drag coefficient of 0.29 for the ordinary E31, a useful achievement in a wide car intended for sustained speed. The number alone does not measure total drag, which also depends on frontal area, but it helps explain the care given to glass, seals, mirrors, and the body’s rearward flow. Aerodynamics supported the driving purpose: less power consumed pushing air, less disturbance around the cabin, and a shape that made its engineering legible without labeling it.
The M70 could be paired with a four speed automatic or a six speed Getrag manual. The manual mattered less as a route to a better brochure number than as a change in ownership of the experience. The driver could choose how the V12 entered a corner or gathered speed afterward, instead of asking the transmission to interpret the request. The same smooth engine now invited participation rather than merely relieving effort.
There was substantial competition. The Mercedes coupe offered space and a mature luxury formula; the Porsche 928 had spent years developing the front engine GT as a driver’s car; Ferrari sold a very different combination of engine character, body design, and expense. The BMW did not erase those distinctions. It added a particularly technical and visually modern answer, one whose performance came with more insulation than some enthusiasts expected from the shape.
A low, exotic looking coupe suggests immediacy. A heavy, thoroughly equipped grand tourer delivers stability and comfort at a cost in agility. The E31 carried enough mass that the original M70’s output did not turn every acceleration into an event. Its sophistication was easier to appreciate over a long journey than in a short demonstration intended to prove that an expensive BMW was faster than something cheaper.
The generous front accommodation, integral seatbelt arrangement, and complex side glass illustrate where some of the money and weight went. Removing a pillar is not simply deleting a piece of metal. Loads have to find other paths, seals have to remain aligned, and the seats acquire structural responsibilities. The resulting openness is lovely. It is also an engineered condition that an aging car must continue to maintain.
Eight cylinders, then a larger twelve
The V8 840Ci, introduced in 1993, tested how much of the car’s attraction actually depended on 12 cylinders. It preserved the shape, accommodation, and general touring purpose at a lower position in the range. That was not a dilution so much as a useful experiment. An owner who cared more about the car than the engine badge could acquire most of the proposition without buying its most elaborate powertrain.
The V12 nevertheless remained the E31’s defining engine. Its long banks and paired intake systems gave the engine bay a visual order that matched the car’s deliberate surfaces. Underway, its appeal depended less on being constantly spectacular than on remaining smooth while the car covered distance. The V8 alternative made that preference clearer by offering so much of the same grand tourer without it.
BMW’s naming change and engine change occurred separately. The 850Ci designation appeared while the 5.0-liter M70 was still fitted. The 5.4-liter M73 followed in 1994, with a five speed automatic, more torque, and revised valve gear. A later badge is therefore not an adequate substitute for checking the actual car. Even a flagship occasionally requires someone to read past the trunk lid.
The M73’s larger displacement and lower friction roller rocker arrangement improved the original idea without changing its basic architecture. It retained one camshaft per bank and two valves per cylinder. More ratios let the transmission choose a more suitable engine speed without relying on a large jump between gears.
Ferrari’s 412 was nearing the end of a long development line when BMW arrived. The E31’s new body and electronics made an immediate contrast with that familiar shape, but the later 456 would offer a much more modern Ferrari answer. The BMW’s advantage was partly timing: it entered while several expensive coupes were approaching replacement.
The next generation of rivals made the distinctions sharper. Ferrari’s 456 emphasized a more sporting interpretation of the front engine V12. Bentley’s Continental R paired a turbocharged V8 with great scale and a highly individual cabin. The Aston offered another tradition altogether. The 850i could look more contemporary than one and less demonstrative than another without defeating either on every criterion. Its strongest claim was to a particular combination, not universal supremacy.
The E31 occupied an awkward commercial position. Its substantial price and limited rear accommodation narrowed the audience, while its weight made it less urgent than the exotic shape might suggest. Buyers who wanted a sports car could find sharper ones; buyers who wanted a limousine had little need for the smaller cabin. Its strongest audience was the driver who specifically wanted the distance between those two categories.
Motorsport took the brief apart
The 850CSi gave the coupe a more forceful response. Its S70B56 enlarged the M70 concept to 5.6 liters and retained the single cam, two valve arrangement, but revised the breathing and calibration. BMW’s European specification listed 380 PS and 550 Nm, approximately 375 hp and 406 lb-ft, with a six speed manual as the only transmission. The suspension, steering, brakes, and exterior details received corresponding attention. The badge understated a substantial Motorsport intervention.
The experimental M8 went much further. BMW’s retrospective describes a 6.0-liter V12 with four valve breathing, carbon fiber intake hardware, and roller throttles that cleared the intake path at full opening. BMW quotes 640 metric horsepower for the prototype. Its intake and lighter construction suggest how different the result might have been from an ordinary 850i, but the company did not record official acceleration measurements. BMW eventually displayed it publicly rather than building it for customers.
Gordon Murray’s McLaren required a different answer again. The S70/2 was designed for a very light road car with demanding length, weight, response, and lubrication requirements. Its 6.1 liters, four camshafts, four valves per cylinder, individual throttles, and dry sump put it in a different mechanical category from the 850CSi’s two cam engine. The shared S70 nomenclature records a relationship within BMW Motorsport; it does not turn one design into a lightly modified version of the other.
The dry sump helped keep the engine low without sacrificing oil supply under cornering loads. Individual throttles reduced the intake volume that had to fill when the driver opened them, helping the engine respond quickly. High speed breathing produced the famous 627 bhp, but Murray also required tractability in ordinary traffic. That combination is the interesting connection to the sedan program: very different hardware, still expected to behave properly when it was not performing for an audience.
The competition chronology is equally distinct. A McLaren F1 GTR won Le Mans in 1995 with BMW power; BMW’s own V12 LMR won in 1999. The racing developments associated with the S70/3 required endurance lubrication, cooling, and regulation specific tuning, not merely more output. The X5 Le Mans then demonstrated how startling the same expertise could become when assigned an inappropriate silhouette. A racing V12 beneath an SUV hood is an excellent way to ensure that nobody mistakes a feasibility study for a sensible product proposal.
Italdesign provided a more conventionally exotic setting. The 1991 Nazca M12 placed the 850i’s 5.0-liter V12 amidships in a light composite concept. The 1993 C2 Spider used an engine from the 850CSi program. These were direct applications of production related engines, unlike the bespoke McLaren unit. Moving the engine into a lighter body exposed possibilities that the fully furnished BMW coupe deliberately traded away.
The E31 and its surrounding experiments demonstrate the range of BMW’s V12 ambitions, but also their boundaries. A grand tourer, a supercar, and an endurance racer do not become excellent through the same choices. The luxury sedan’s next step was less spectacular and more commercially important: improve the familiar car without asking it to become something else.
