Mechanical details of the forthcoming BMW M3 sedan and BMW M4 coupe have finally been released, with a 3.0-litre twin-turbocharged six-cylinder engine and six-speed manual transmission now officially confirmed.
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BMW has announced both M3 and M4 models will weigh "just under" 1500kg and be powered by a "high-revving" (more than 7500rpm) 3.0-litre in-line six-cylinder putting out "approximately" 316kW and peak torque "far beyond" 500Nm thanks to the use of two mono-scroll turbochargers.

In terms of specific outputs, the M3 and M4 engine produces around 105kW per litre of capacity, and based on 500-550Nm, 166-183Nm/litre. These numbers place it ahead of benchmark production six-cylinder engines such as the 3.8-litre twin-turbo Porsche 911 Turbo (101kW/litre and 174Nm/litre) and 3.6-litre twin-turbo Cadillac CTS (87Nm/litre and 162Nm/litre). In terms of specific power output, it also falls just shy of the 3.8-litre twin-turbo Nissan GT-R (107kW/litre) but beats it for specific torque output (165Nm/litre).

New BMW M3/M4 Engine

BMW says while the figures improve on the outgoing 309kW/400Nm naturally aspirated 4.0-litre V8-powered M3 "by well over 30 per cent" fuel consumption and emissions have also been reduced by "around 25 per cent".

This has been aided by using light-weight carbonfibre reinforced plastic (CFRP) on the roof, roof bow, drive shaft and front end strut brace, as well as a boot lid made of a carbonfibre-shield moulding compound (C-SMC).

Both cars will come as standard with a six-speed manual transmission with an automatic downshift rev-matching feature. A seven-speed dual-clutch automatic transmission will be optional and is accompanied by an integrated launch control function. Regardless of the gearbox selected, power will be transferred to the rear wheels via a new Active M limited-slip differential that, unlike the mechanical system used by the outgoing M3, employs an electric actuator to constantly vary the locking effect as required.

BMW M GmbH president Friedrich Nitschke said the BMW M3 sedan and M4 coupe represent an ongoing commitment to the performance division’s philosophy of blending motor sport genes and uncompromised everyday usability within an emotionally rich overall concept.

BMW M3, M4 - C-SMC Boot

"The engine is the heart of every M model, and the example fitted in the two new cars combines the virtues of a high-revving naturally aspirated unit with the strengths of turbocharger technology," Nitschke said.

"The BMW M3 and BMW M4 take motor sport technology from the track to the road, and thousands of laps of the legendary Nurburgring Nordschleife – the world’s most demanding race track – have readied the new models for that transition."

The M3 and M4 are due to arrive locally in mid 2014 following an anticipated twin premiere at January’s Detroit auto show.

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BMW M3, M4 - 4