The BMW M5 and M6 are ultra-high-performance sports cars with exceptional dynamic abilities which have been carefully tuned by M engineers on racetracks around the world under all conditions. Simultaneously, the BMW M5 and M6 bring new standards for daily driving comfort and features. To achieve these lofty goals, the new BMW M5 Sedan, M6 Coupe, and M6 Convertible share the most powerful engine ever fitted in a series-produced model from BMW M GmbH mated to a high-torque 7-speed M-Double Clutch Transmission (M-DCT). An innovative Active M Differential further splits power transfer between the rear wheels. This drivetrain, combined with extensive chassis and suspension upgrades ensure that the engine’s performance can be transferred to the ground.
The new engine shared by the BMW M5 and M6 has the highest output ever generated by a BMW M car, and at the same time provides the most efficient balance between performance and fuel consumption. It is characterized by immediate throttle response, a linear power band and an unusually high and flat torque curve. The new engine produces around 10% higher output than the V10 engine of its predecessors and torque is up by over 30%. At the same time, fuel efficiency has improved by nearly 25 percent.
To achieve the performance levels demanded by the BMW M5 and M6, the engineers at BMW M started with the proven BMW M developed V8 engine from the BMW X5 M / X6 M (internally known as the S63) and further developed it for its duty in the latest M5 and M6 models. Internally designated as the S63Tü this new engine uses similar M Twin Power technology combined with the reverse flow V8 layout. The result is that the high-revving V8 engine with M TwinPower Turbo Technology lends a whole new intensity to the powerful thrust at higher rev ranges for which M cars are known. The 4.4-liter engine develops a peak output of 560 hp (412 kW) at 5,750 – 7,000 rpm (versus 555 hp at 6,000 rpm for the S63), while its maximum torque of 500 lb-ft (680 Nm) is on tap between 1,500 and 5,750 rpm (versus 500 lb-ft from 1,500 to 5650 rpm for the S63). The rev limiter intervenes at 7,200 rpm (up 200 rpm from the S63 engine). The rev band, which offers extremely dynamic acceleration between peak torque and the availability of maximum output, is therefore almost three times as wide as that of the V10 engine in the previous generation M5/M6.
As in the V-8 engine of the X5 M, the two twin-scroll turbochargers, along with the catalytic converters, are placed in the V-space between the two cylinder banks in a reverse flow layout. This layout results in an unusually compact engine where the intake is moved outboard and the exhaust inboard – the opposite of conventional V-engines. The lengths of intake and exhaust tracts are thereby reduced and their diameters increased, reducing pressure losses – especially on the exhaust side. A further advantage of the layout is the short distance between the cylinders’ combustion chambers and the primary catalytic converters; this leads to quicker warm-up of the catalysts after the engine is started and therefore lower start-up emissions.
The patented cross-bank exhaust manifold, first introduced in the S63 engine of the X5 M / X6 M is also employed in the S63Tü. This exhaust manifold is a special 8-into-4 setup that combines the exhaust from two cylinders (on opposite banks) that are 360 degrees of crankshaft rotation apart from each other. Each of the eight runners is of identical length to ensure perfectly regular timing of exhaust gas pulses.
Each of the four manifold outlets is fed into each of the four available scrolls of the two twin-scroll turbochargers. The two scrolls of a twin-scroll turbo lead each exhaust pulse directly to the turbine without feedback or interference from the other scroll (that are fed by cylinders at other points in the combustion process). Additionally, dividing the gases into two smaller paths (scrolls) results in higher gas velocity than a single larger path. This enhances the turbocharger’s response thereby reducing lag. The crossover manifold is configured so that the second scroll of the turbo is fed by two cylinders that are 180 degrees out of phase with the first scroll. In this way each turbocharger receives distinct exhaust pulses every 180 degrees of crankshaft rotation (from one of four cylinders). Furthermore, the two turbos receive exhaust pulses that are 90 degrees offset from each other. The result is that throttle response is sharpened and turbo lag is reduced to a minimum. The new engine also sports larger intake runners, larger air to liquid intercoolers and a tuned exhaust which results in the engine making power more quickly than previously possible. Finally, the S63Tü uses a maximum boost pressure of 1.5 bar (21.7 psi) versus 1.2 bar (17.4 psi) for the S63 engine.
BMW’s efficient High Precision direct fuel injection also plays a major role in this engine’s combination of high performance and fuel efficiency. High Precision direct fuel injection ensures an extremely precise supply of fuel to the combustion chambers. Injectors positioned centrally between the valves within immediate range of the spark plugs spray the fuel into the combustion chambers with maximum pressure of 200 bar (nearly 3000 psi), providing smooth and clean combustion. Innovative solenoid valve injectors in the new BMW M5/M6 engine use multiple injections per combustion cycle to achieve an extremely precise mixture preparation. The fuel also has a cooling effect on the combustion that allowed the M engineers to endow the engine with a high compression ratio of 10:1. This high compression ratio contributes to both performance and efficiency, while reducing exhaust emissions – and even has a positive effect on engine sound.
Throughout its history, the heart of the BMW M5 and M6 has been its high-revving, high output-per-liter engine fed by individual throttle plates. The new engine introduces VALVETRONIC variable valve control system to a BMW M engine – effectively providing 16 individual throttles.
VALVETRONIC is BMW’s patented fully variable valve control system that eliminates the need for conventional throttles. Engine power is instead controlled directly by varying the amount of lift of the intake valves. Pumping losses are minimized with this system and resulting in efficiency and torque improvements. VALVETRONIC has also sharpened the responsiveness of this engine compared to the V10 engine it replaces.
The M TwinPower Technology of the new V8 engine also includes BMW’s Double VANOS infinitely-variable valve timing system which optimizes the engine’s efficiency and generates high torque at low engine revs. In addition, a volume-controlled oil pump and a range of other EfficientDynamics measures deliver an extra boost to efficiency. The new BMW M5 and M6 feature both Brake Energy Regeneration and the Auto Start-Stop function, which automatically switches off the engine when the car comes to a stop.
The engine’s exhilarating thrust gives both models impressive acceleration. The instant power delivery and sustained thrust of the engine results in acceleration of 0 – 60 mph in 4.1 seconds for the Coupe and 4.2 seconds for the Convertible. The top speed of both models is electronically limited to 155 mph (250 km/h). The sprint for the BMW M5 from rest to the 60 mph (0-100 km/h) mark is all over in 4.2 seconds (4.3 for the 6-speed manual) and from that point progress continues with barely any let-up. Maximum speed is electronically restricted to 155 mph (250 km/h). While the engine’s output has increased by around 10% and maximum torque is up by more than 30%, the new BMW M5 and M6 models consume roughly 25% less fuel and have a highway range about 34% higher than their predecessors.
M TwinPower Turbo Technology also shapes the development of the V8 engine’s soundtrack. The concept of crossover exhaust manifolds plays a key role in delivering a multi-layered collage of sound. The twin-tailpipe exhaust system of the new BMW M5 and M6 runs largely in a straight line and has a large cross section. The two exhaust pipes feed into a single muffler from which the customary M quad tailpipes extend out through the far left and right-hand sides of the rear diffuser.
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