BMW M5: Muscles from Munich

The numbers are in and all bets are off.

Bavarian Motor Works has announced the official specifications of it's 10-cylinder engine, and figures like 520Nm and 8250rpm are simply astounding.

In keeping with its racing bloodline, the M5 surpasses the magical 100bhp per litre output, and its specific output is in fact on par with that of many serious racing cars.

While BMW is best known for its popular inline or straight engines, it has proven that it also knows how to tune a V-configured powerplant - and Porsche, Audi and Mercedes-Benz will no doubt be disseminating every last tidbit of this information as BMW gears up for what could be its most important launch in history.

The new M5 will be a super saloon unlike any other in that it's large-capacity, 10-cylinder engine will spin freely past 8000rpm, and you can thank years of Formula One technical know-how for that.

For the E60 M5 sedan is due on sale in Australia mid-2005, and the engine shares more than just its number of cylinders with the Formula 1 engine that powers the BMW WilliamsF1 team, which we'll get to later.

As you would expect from BMW M, this high-performance normally aspirated engine generates enormous pulling force over its entire speed range, and it's light too, tipping the scales @ 240 kilograms.

The M5's V10 boasts a cubic capacity of 5.0-litres and produces a maximum output of 378kW (507bhp) and a maximum torque of 520 Newton metres, making the M5 the most powerful production model in the BMW line-up.

5.0-litre V10 Specs:

378kW @ 7750rpm
520Nm @ 6100rpm

BMW is confident the new M5 will outperform its competition when it comes to acceleration as well.

Torque of 450Nm is already on tap @ 3500rpm and 80 per cent of maximum torque is available @ up to 5500rpm, which is a wide speed range for an engine of this calibre.

Before we go any further, let's look at how V10 is able to rev so freely and with such a high rev ceiling:

The 5.0-litre V10 boasts a redline of 8250rpm and compared to the previous M5 V8 engine, performance has increased by a whopping 25 per cent.

The twin five-cylinder banks of the V10 are arranged at an angle of 90° to achieve a mass balance of the crankshaft drive, optimised for low vibration and increased comfort.

The extremely stiff crankshaft is supported by six bearings the one-piece aluminium cylinder heads of the are arranged in banks.

The V10 power unit features 4-valves per cylinder, a typical BMW trait, and all valvetrain components are of low mass.

Thus, the M engines feature for the first time low-weight, flow-optimised 5mm shaft valves, spherical valve tappets with hydraulic valve play compensation and single valve springs.

All this results in a considerable mass reduction, which is a prerequisite for a high-revving engine.

The bi-VANOS variable valve timing featured in the new M5 engine ensures increased performance, an improved torque curve, optimum responsiveness, lower consumption and fewer emissions.

Thanks to the bi-VANOS technology, intake and outlet valves are always opened and closed at precisely the right moment.

The naturally aspirated engine uses ten flow-optimised intake trumpets to “inhale” air from two intake plenums. Each cylinder has its own throttle, a feature typical of racing cars.

All throttles are actuated simultaneously and are electronically controlled in order to make the engine highly responsive in the lower speed range, as well as to achieve an immediate response of the vehicle at the high end of the performance spectrum.

The exhaust system of the new M5 engine is another important facet of achieving the manic 378kW of power, and so is understandably made of [seamless] stainless steel and has a dual-flow design all the way to the silencers/mufflers.

The exhaust gases leave the system through four tailpipes, now a regular M trademark and the exhaust system also complies with the European EU4 and the US LEV2 emission standards.

The engine management system (codenamed MS S65) is the central factor behind the V10's outstanding performance and emission data. With more than 1,000 individual components, this engine management system is unparalleled in its package density.

Its processors are the most powerful currently approved for use in automobiles, as high engine speeds and comprehensive management and control tasks demand the utmost from this system. Just hope it never gets a virus then, or the engine's stuffed.

Another feature that BMW will be pushing when it launches the M5 is the new 7-speed SMG gearbox, that promises to make the most of the engine by getting to the power to the rear wheels with the tiniest of delays.

BMW M is the first manufacturer worldwide to offer a 7-speed sequential gearbox, but you can bet that Mercedes is not far behind. Even more highly refined than the previous six-speed transmission, the seven-speed SMG gearbox enables manual gear selection with ultra-short shifting times as well as comfortable cruising thanks to the automatic gear selection mode, and it is technically designed to handle a torque of up to 550 Newton metres and engine speeds of up to 8500rpm. Here's looking at a CSL model to see such figures.

The purpose of the additional 7th gear is to reduce engine speed and torque gaps.

The new seven-speed SMG gearbox allows gears to be changed using the central gearshift lever or via paddles mounted on the steering wheel. Compared to the previous SMG transmission, gear change times are increased by 20 per cent, which is incredibly impressive, considering the the previous version was remarkably quick anyway.

The advantage for the M5 driver is a smooth and super slick gear-change, accomplished at speeds impossible to reach even by the most proficient driver, thus smoothing out the traditional imperfections in the power flow through the gears.

BMW is adamant that M5 drivers will feel an almost jerk-free power delivery when punching the throttle, from standstill all the way up to its top speed.

Thanks to the SMG's drivelogic function, the driver can choose from eleven gear change options, which enable them to adapt the SMG's characteristics to their very own style of motoring.

Six of these programs can be preselected in the sequential manual gearbox mode (S mode), and the spectrum ranges from balanced dynamic to very sporty. With the gearbox in the S mode, the driver always shifts gears manually.

Whenever the driver activates the Launch Control function, the SMG Drivelogic shifts gears shortly before the maximum engine speed is reached at precisely the right moment and with optimum slip until the M5 reaches its top speed.

In critical situations, when the driver shifts down on a slippery surface, for example, the gearbox opens the clutch in the fraction of a second in order to prevent the M5 from swerving out of control in the event of excessive drag torque at the driven wheels.

The most powerful production engine in the company's history is manufactured along with other BMW special engines on a highly flexible production line at the BMW plant in Munich, Germany.

The most stringent quality standards are met in the mechanical production and assembly of the high-revving engine. As the materials and components are exposed to heavy loads, extremely high demands are placed on surface quality and production tolerances.

Some parts and components are processed at a precision of up to one thousandth of a millimetre.

So there you have it - BMW's most powerful engine ever built will probably also be one of the best burnout tools ever built as well, and though no 0-100km/h times were supplied, expect a 4.6 second time -- possibly less if overall weight can be kept to a minimum.

The high revving V10 will no doubt go down in history as one of the most powerful naturally aspirated 5.0-litre engines ever built, and is a testament to BMW M division's technical prowess. Did we mention 378kW and 520Nm?

The M5 is due on sale in Australia mid-2005 and pricing and further specification details will be announced closer to launch, but rest assured it won't come cheap.