The F01: boost replaces the argument
The 7 Series introduced in 2008 looked like BMW had finished an argument with itself. Its surfaces were calmer, its proportions more familiar, and its controls less determined to make every previous owner a beginner. The V12 followed in 2009, reaching the United States as the 2010 760Li. Under that comparatively sober body, BMW changed its approach to the engine more substantially than the styling suggested.
The N74 retained the 60-degree layout, four valves per cylinder, and direct injection, but added boost. Where the N73 had enlarged the naturally aspirated engine’s breathing capacity, the N74 increased the amount of air entering it under pressure. The result was substantially more torque available much earlier, reducing the need to reach high engine speeds before a large acceleration. That suited a limousine better than a peak power figure alone could suggest.
Compressing air heats it, reducing its density and increasing the tendency toward knock. The N74 therefore used charge coolers with a separate coolant circuit. Its turbos sat outside the cylinder banks rather than inside the V. Valvetronic was absent, although variable camshaft timing remained. This was a different collection of compromises, not simply an N73 with two extra devices attached. Boost saved no one the work of managing combustion, heat, or throttle response.
The accompanying eight speed automatic mattered almost as much. More ratios gave the transmission more ways to place the engine in its useful range; electronic coordination could then smooth the handover between gears and boost. In its 2009 drive, Car and Driver observed normal second gear starts and rapid multiple ratio downshifts. Those are two ends of the same brief: avoid a lurch when leaving the curb, but do not hold a long conference when the driver asks to pass.
That response could be more useful than the earlier V12’s willingness to rev. A luxury engine spends much of its life below its maximum output, moving a considerable mass without announcing each adjustment. A broad torque delivery allows small changes in speed with smaller changes in engine speed. It also creates a new problem when the accelerator calibration delivers too much too suddenly. Turbocharging increases the available force; refinement depends on how accurately the driver can request it.
The F02 combined this powertrain with a long cabin, substantial insulation, and chassis systems descended from the E65’s attempt to reconcile ride with body control. It was not a return to an analog BMW. The more familiar interface merely made the technology less conspicuous. That was an improvement precisely because the driver no longer needed to admire the system in order to operate the car.
The Mercedes S600 and S65 supplied credible alternatives on either side of the BMW’s intended temperament. Greater output did not settle the comparison, any more than the BMW’s quieter presentation did. Accelerator response, transmission decisions, ride, seating, and noise under load determined how the capacity was experienced. By this stage, the contest had moved well beyond whether 12 cylinders could make a sedan fast.
Sharing the engine family with Rolls-Royce gave BMW a broader base over which to develop it. In the heavier Ghost, the V12’s value was its ability to accept greater mass and different gearing without making the powertrain conspicuous. The V12 still offered a particularly agreeable starting point for that work. Sharing a starting point was not the same as sharing a finished car.
Meanwhile, the V12’s competition was moving inside the same showroom. Turbocharged V8s could deliver immense torque in a shorter package with fewer cylinders to feed and service. Electric assistance offered another way to supplement combustion at low speed. Neither development erased the V12’s balance, but both weakened the claim that its particular complication was necessary to obtain effortless acceleration.
The old expense also remained. Two banks of cylinders, turbochargers, charge cooling, fuel systems, and densely packed auxiliaries had to age somewhere beneath the sound insulation. Their failure rates cannot be inferred from the number of parts, but their repair does not become cheaper because the car has depreciated. An owner can acquire the flagship for a fraction of its original price without acquiring a corresponding discount on the work required to keep it a flagship.
The F02 thus left the V12 with a more exposed purpose. It no longer had an exclusive claim to exceptional performance, and it had never held an exclusive claim to quiet. What remained was a particular combination of firing regularity, response, sound, and reserve. The next generation made the V12 much faster while V8s and electric motors continued closing the gap in the qualities that once justified twelve cylinders.
