BMW boosts power for M3 and M4

BMW has confirmed its forthcoming new M4 and M3 performance twins will get more power and torque than the outgoing models, despite a one-litre reduction in engine capacity.

The German car-maker is retiring the outgoing M3’s naturally aspirated 4.0-litre V8 in favour of a new twin-turbocharged 3.0-litre in-line six-cylinder petrol engine producing 316kW of power and "far beyond" 500Nm of peak torque.

This represents an 7kW boost in power over the V8, while torque is up by 100Nm, or “well over 30 per cent”, for the new models ahead of their expected local debut next year.

BMW is also claiming a 25 per cent improvement in fuel efficiency with the new engine, pointing to a possible new figure of around 9.3 litres per 100 kilometres, compared to 12.4L/100km in the current model.

As well as the smaller capacity engine, the reduced fuel consumption can be also put down to weight-saving measures including extensive use of carbon-fibre reinforced plastic (CFRP) on the body and in some mechanical components.

While BMW fitted the previous generation M3 Coupe with a CFRP roof, both the new M3 sedan and M4 Coupe will benefit from the light-weight material.

The kerb weight of the M4 is reduced to less than 1500kg, which is a drop of around 80kg over the outgoing model. BMW says this was to ensure “outstanding driving dynamics and exemplary efficiency”.

Perhaps unsurprisingly, BMW tested the M3 and M4 on the Nordschleife circuit of the famed Nurburgring track in German and the company says the motor sport expertise of its M engineers can be felt in the performance of the cars.

In fact, it went a step further by asking BMW DTM drivers Bruno Spengler and Timo Glock to test the cars and assess the suspension, tyres and powertrian at Nurburgring, providing feedback to the M engineers.

The twin-turbo engine comprises two mono-scroll turbochargers, direct injection, Valvetronic variable valve timing and variable camshaft timing.

BMW says the variable valve and camshaft timing provides “fully variable control of intake valve lift” and allows smoother delivery of power and greater efficiency, while allowing for sharper throttle responses.

Electrically controlled flaps near the rear muffler in the twin-pipe exhaust system ensure the M3 and M4 produce a “BMW M sound which is striking and unmistakable over the entire engine speed range, as well as giving precise feedback on engine load”.

Both vehicles will be matched with a standard six-speed manual gearbox that is 12kg lighter than the previous unit, assisting the car’s optimum weight distribution.

According to BMW, the gearbox works more quietly than before, and blips the throttle on downshift, which previously only occurred when mated to the double-clutch transmission.

The optional seven-speed M double-clutch transmission features a manual mode that does not interrupt the flow of power, a launch control function for an extra kick from a standing start, and the choice of different modes for comfort, performance or economy.

The redesigned rear axle is lighter thanks to the use of forged aluminum, while the connection between the rear axle sub-frame and the body is borrowed from BMW motor sport.

Even the tyres have been engineered in tandem with the rest of the car since the start of development. The specially developed forged wheels are said to have an impact on the dynamics and efficiency of the new models.

A new electro-mechanical steering system has been developed for the new models, and BMW claims it offers precise feedback and a direct steering feel.

Comfort, Sport and Sport+ modes adjust the steering feel and suspension settings to suit the driver.

BMW ripped the covers off the gold-coloured M4 concept at the Pebble Beach Concours d’Elegance in the US in August, revealing a slightly more aggressive design than the current M3 Coupe with two huge air intakes flanking a lower air dam cooling the engine and brakes.

A crease runs along the side, between the chunky wheel arches that house the huge 20-inch wheels, while the rear features a lip spoiler built into the boot.

Unfortunately, the images released by BMW this week show a pair of camouflaged M test cars and do not reveal anything further about the final design of the production model.

While BMW Australia is yet to confirm a release date for the M3 and M4 locally, it is expected to arrive sometime next year, possibly in the first half with a cabriolet version to follow shortly after.