BMW M6 UK Launch

Press Release

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BMW's V10 wins hearts and minds: The perfect ten

Highlights

• The most sophisticated BMW production car engine ever

• 2005 International Engine of the Year

• Formula 1-inspired technology and manufacturing processes

• In-house electronic 'brain' making 200 million calculations per second

• Naturally aspirated for engineering purity

Designed and built by BMW, the ten-cylinder heart of the M6 is forged from Formula 1 principles, and is officially the best engine in the world.

International Engine of the Year

Nearly ninety years after BMW began its life producing aero engines, the judges of the 2005 International Engine of the Year awards unequivocally crowned BMW's new V10 naturally-aspirated powerplant as the number one engine in the world. More successful than any other manufacturer in these highly regarded industry awards, with 26 trophies in all, BMW rightly prides itself that the engines it produces today offer the finest blend of power, response, and economy. A blend wrapped in an emotional aura distilled in the sound of an M engine at full throttle.

With a history steeped in the production of first aeroplane engines, then racing and road-going motorcycle and car engines, it is only natural that BMW offers the widest choice of engine configurations of any brand worldwide. One, two and four-cylinder motorcycle engines and four, six, eight, 12 and now ten-cylinder engines make BMW the most prolific of all.

First high revving V10 engine in a production car

The V10 petrol engine has so far been the exclusive preserve of racing cars and exotic low volume sports cars. 2005's M cars (M5 / M6) break the mould as the first series production cars equipped with a high revving V10. This five-litre unit produces 507hp allied to a torque of 520 Newton metres with an engine speed peak at 8,250rpm.

Equally impressively, these statistics are achieved without any form of forced induction: this is a pure thoroughbred that achieves a specific power output of no less than 101.4hp per litre - a remarkable result from such a large capacity engine.

Achieving a new performance benchmark

507 horsepower is a new peak for BMW, but achieving this milestone is more than just a matter of increasing power. In order to stand out in an ever-increasing market for performance cars it was essential to balance the power with an engine performance fit for the fastest ever M car.

BMW engineers considered three possible routes to boost performance:

· increase cubic capacity thereby raising torque,

· forced induction via a turbocharger or supercharger or,

· develop a high revving engine to increase torque

The conclusion was that there is more to an engine than pure output. Acceleration characteristics and driving dynamics are equally, if not more, important, both of which are dependant on forward thrust and vehicle weight. The forward thrust delivered by the driven wheels is the result of the blend of torque, power and gearing. Would BMW's traditional concept of a high revving engine with a close ratio gearbox and an appropriate final drive ratio realise this blend and unleash the desired drive forces and driving experience?

Separating the wheat from the chaff

Deploying the cubic capacity or forced induction route may well deliver the similar power and torque statistics, but both routes present drawbacks.

Increasing the engine size adds weight at the front of the car, requires more space under the bonnet and increases fuel consumption. Supercharged engines also have drawbacks. Rarely do they excel in the fuel economy stakes and their response to driver inputs is never as spontaneous as a purebred normally aspirated unit. Forced induction engines also offer very high levels of torque, but therefore require massively reinforced, and therefore heavy, drivetrains.

High revving, instant power, naturally

So, BMW M engineers chose the third option of a high-revving, naturally aspirated engine as the perfect solution for the new M5 and M6. It was a far more challenging approach and much more difficult to bring such a concept to reality but, in BMW M's view, it was worth these sacrifices for the purity and integrity of the whole design.

This solution only adds 20 Nm of torque to the engine's spiritual predecessor, the E39 M5's 5.0-litre V8, but it is the sophisticated combination of power, torque and gearing that places it on a new plane as far as driving dynamics is concerned. It reaches maximum torque at 6,100rpm and 450Nm is available from 3,500rpm. This is a very wide engine speed range for such an engine and fully exploitable through the car's seven speed SMG manual transmission.

Brains and brawn

But the beauty of this engine is that it combines traditional engineering principles with the most technologically advanced electronic systems. It truly is unique.

Mastermind

BMW's V10 is controlled by the MS S65 engine management system that can perform over 200 million individual calculations per second, a new record for a regular production car engine. Made up of more than 1,000 individual components it co-ordinates all engine and gearbox functions via different control units.

This is not a component bought in from outside BMW: the hardware, software and functioning of MS S65 are all BMW M in-house developments and it is one of the main reasons for the M6's outstanding performance and emissions data.

High engine speeds demand high performance electronics

The demands placed on the MS S65 control unit are many and varied. Not least by the engineers' insistence of a naturally aspirated high-revving engine and the large number of control and regulation tasks required. Therefore the control unit has three 32-bit processors that perform an incredible 200 million individual calculations per second.

Compare this to the not exactly slovenly E46 M3 control unit presented only four years ago and the new system represents a performance increase by a factor of eight. It has ten times the memory capacity too.

The brain behind the brawn

Receiving over 50 input signals, the system calculates the optimum ignition point, the ideal cylinder charge and the injection quantity for each individual cylinder on each individual combustion cycle. At the same time MS S65 calculates the optimum camshaft angle and the ideal position for each of the ten individually controlled throttle butterflies, and then makes the necessary adjustment.

The system also manages many ancillary functions:

• It manages the electronic throttle valve control on a power and torque matrix according to a potentiometer on the accelerator pedal. This meets the driver's wish for power and performance. The power and torque manager adjusts requests by adding power signals from auxiliary engine units such as the air conditioning compressor and the alternator.

• Functions such as idle speed control, emission control and knock control are also coordinated and aligned to the maximum and minimum output and torque curves permitted by DSC (Dynamic Stability Control) and EDFC (Engine Drag Force Control). The target output and torque calculated in this way is maintained while taking into account the current ignition angle.

• MS S65 also carries comprehensive on-board diagnosis for use by BMW service engineers.

• The engine management system manages new and innovative ionic current technology to manage engine 'knock', misfiring and combustion 'misses'. See more detail at the end of this section.

• A 'Power' button beside the gear lever allows a 400hp or 507hp engine programme to be selected. Each time the M6 is started it is in P400 mode: in other words, the engine is programmed to deliver 'only' 400hp. This is to suit normal urban traffic conditions when the driver doesn't necessarily want 507hp on tap. Pressing the POWER button brings in the full 507 horses. The 507hp setting can be pre-selected in MDrive Manager and activated immediately from the MDrive button on the steering wheel, along with other bespoke selections. See section 5 for more details.

The V10's electronic wizardry is working its magic on tried and trusted, but still state-of-the-art, BMW engineering principles. Since the launch of Bi-VANOS technology on the E36 M3, BMW's engines have been fine-tuned to offer the best systems for air intake and exhaust.

Breathe in

The new V10 engine features Bi-VANOS variable camshaft control pioneered on the 1995 M3, and now available across the range of petrol models. This latest incarnation ensures the optimum charge cycle helping to achieve very short adjustment times.

The adjustments of camshaft position relative to the crankshaft are infinitely variable and map-controlled. The Bi-VANOS allows a variation of the angle of the intake cam by up to 66° while the outlet varies by a maximum of 37° relative to the crank. These angle adjustments are a function of accelerator position.

In practice this means increased performance, an improved torque curve, optimal response to driver inputs, lower fuel consumption and fewer emissions. For example, at the lower end of the load and engine speed range the engine increases valve overlap thereby boosting internal gas recirculation. This reduces charge cycle losses and lowers fuel consumption.

The M Bi-VANOS technology requires very high oil pressures to achieve ultra-precise high-speed camshaft adjustment. A radial piston pump in the crank chamber increases engine oil pressure to 80 bar and this map-controlled high-pressure adjustment permits optimum angles, precise ignition points and injection quality under all conditions.

Breathe out

Although the intake system contributes a considerable amount to the performance of the new M6 engine, the importance of the exhaust cannot be underestimated.

Two stainless steel 5 into 1, equal length, tubular manifolds carry the exhaust gases from the engine. To achieve exact pipe diameters, the seamless pipes are formed from the inside using an interior high pressure forming technique (hydroforming) at a pressure of up to 800 bar. The pipe walls have a thickness of just 0.8mm, a sign of the M engineers' incredible attention to detail.

A paragon of cleanliness

Two trimetal-coated catalytic converters per exhaust clean the exhaust gases to meet European EU4 and American LEV2 standards. There are two underfloor catalysts and two more close to the engine. In conjunction with the thin-walled exhaust manifolds, these catalysts quickly reach their optimum operating temperature, even after a cold start.

The exhaust gases finally leave the system through four prominent tail pipes that give the M6 so much character from the rear and they produce a symphony for car lovers, both inside the car and out. A sound that echoes the spiritual home of M GmbH, the Nurburgring - where all BMWs are tested to the limits.

Motorsport technology takes to the road

With M born of a desire to replicate motorsport performance in a road-going car, it will not escape the notice of aficionados that the new M6 engine shares the V10 configuration with the most recent of BMW's F1 engines. It is not, of course, directly related, it is a 5.0 litre and the F1 engine is a 3.0 litre - but apart from sharing the V10 layout, it is a high-revving engine like the F1 unit and much inspiration for the electronics and engine design was drawn from F1 experience.

The high-speed nature of the engine is a case in point. The new ten-cylinder has broken the 8,000rpm barrier reaching a maximum of 8,250rpm. At 8,000rpm each piston covers 20 metres a second. At 18,000rpm the pistons of the F1 engine move at 25 metres per second. The difference is that the M engine must last for the life of the M6 while the F1 engine only has to travel 500 miles or so.

It is abundantly clear that the M6 engine has basic technological principles, production methods and materials in common with the F1 engine. It is the product of technological transfer.

The M6 blocks are cast at the BMW light alloy foundry in Landshut, the same place as the F1 engines. The engine features a Formula 1-inspired bedplate design for the crankcase that provides a compact and extremely stiff configuration to withstand the very high engine speeds, combustion pressures and high temperatures. Finally, another motorsport-inspired technology is that each of the ten cylinders has its own throttle butterfly and each cylinder bank is served by its own activator.

Technical Highlights

Weightwatcher

Every gram counts when building an engine to the lowest possible weight. The weight saving measures made in the new BMW M6 engine are too numerous to detail but below are a few highlights:

• The very stiff and finely balanced crankshaft made of forged high tensile steel carried in six bearings weighs a mere 21.8kgs.

• Each piston is made of high temperature resistant aluminium alloy with an iron coating and weighs only 481.7 grams including gudgeon pins and piston rings.

• Each fracture split connecting rod is 140.7mm long and made of high strength 70MnVS4 steel. They weigh 623 grams each including the bearing shells.

• The two aluminium cylinder heads of the V10 engine are also produced at the BMW light alloy foundry in Landshut. They feature integrated air ducts that are important for rapid catalytic converter warm-up. Each has four valves per cylinder, with valves actuated by spherical tappets with hydraulic valve play compensation. The tappet diameter has been reduced to 28mm and each one weighs only 31 grams.

Compact engine design

• The two cylinder banks are angled at 90° in a Vee configuration with a 17mm offset. 90° was chosen due to low vibration and good balancing properties.

• The cylinder crankcases are cast using low pressure gravity die-casting and are made of hypereutetic aluminium-silicon alloy. This special alloy contains 17 per cent silicon. There is no need for cylinder liners, so the iron-coated pistons run in uncoated bores.

• The M6 engine is a short stroke engine: that is to say the bore at 92mm is broader than the stroke at 75.2mm. Overall capacity is 4,999cc.

• The piston compression height is 27.4mm and the compression ratio is 12:1.

• Diameters of the valves are 35mm (intake) and 30.5mm (exhaust).

• The valves are exclusive to the BMW V10 unit. Each has a shaft only 5mm in diameter thereby improving intake flow.

• Hydraulic valve play compensation automatically provides optimum valve adjustment at all times. This lowers maintenance costs for the customer and ensures the correct valve adjustment at all times.

• Cross flow cooling concept ensures even temperature distribution in the cylinder head and the reduction of temperature peaks. It also minimises pressure losses in the cooling system.

Ten individual throttle valves

Each of the ten cylinders has its own throttle butterfly and each cylinder bank is served by its own activator. This is another system pioneered in motorsport.