BMW on turbo trail

Blown six to power M3 and coupé sibling | by Andrew Frankel

What’s that dripping sound? It’s BMW starting the intermittent feed of information that will lead eventually to the unveiling of the new M3, hopefully early next year. In fact now that the 3-series coupé is called the 4-series, there’ll be an M4 (above) too, ensuring BMW’s naming strategy now covers most of England’s motorway network.

We’ve known for a while that the fabulous normally aspirated V8 motor in the current M3 was for the chop: in these days where car manufacturers must not only be environmentally model citizens but be seen to be so, the idea of building a car with a big V8 – just because that’s what the customer wants – is becoming increasingly anathema.

At the Alfa 4C launch a few weeks back I was lamenting its lack of a creamy V6 motor when a fellow hack leant across and said, “Alfa is dragging itself into the modern world – you should try it, too.”

Anyway, what has now been confirmed is that the M3 and M4 will be powered by a new variant of the 3-litre twin-turbo straight-six motor that’s been a BMW staple for many years now and is already in the M135i. Blowing at 1.3bar, it’s going to develop 424bhp and while that’s a mere 10 extra horses relative to its predecessor its performance will be characterised by its torque, which rises from under 300lb ft to more than 370lb ft at half the revs.

It’s going to be a very different kind of driving experience: you’ll be granted access to all the acceleration it has to offer at little more than idling speed, though if it provides anything like the throttle response or scalp-itching howl of the normally aspirated engine it replaces, it’ll be the first turbo engine in history to manage it. As the V8 was the last M-engine to breathe at atmospheric pressure, this now means the entire range from M135i to M6 now use turbos.

On the other hand, the last M3 was far too heavy and in its sometimes tricky handling, it showed. By using an inherently lighter shell and then using carbon-fibre-reinforced plastic for items as diverse as the roof and propshaft, BMW has pared its weight back from over 1650kg to under 1500kg, which should have a transformative effect on the driving experience. Better news too for those who feared three-pedal footwells would soon also be a thing of the past: BMW has confirmed that the M3 will come with a six-speed manual gearbox as standard and a double-clutch transmission as an optional extra.