First details: New M3’s V8 firepower revealed

WE SAW the next-generation M3 super-coupe emerge as a thinly disguised concept car two weeks ago at the Geneva motor show – now BMW has revealed details of the bahnstorming new high-revving V8 that will power it.

Confirmed for release in Australia by the end of this year - following its global production debut at the Frankfurt motor show in September - the redesigned E92 M3 two-door will, as widely predicted, be powered by a 4.0-litre V8 that produces in excess of 300kW.

Derived from the M5 sedan and M6 coupe and convertible's 5.0-litre V10, the M3’s first ever V8 displaces 3.999 litres and revs to a stratospheric 8400rpm cut-out (even higher than the V10’s 8250rpm rev-limiter).

Exact claimed outputs are 309kW (420hp) at 8300rpm and a bullocking 400Nm of torque at 3900rpm. BMW says 85 per cent of peak torque is on tap from 6500rpm, and that 340Nm is available from 2000rpm.

While at least one of those figures significantly eclipses the numbers offered by the twin-turbo 335i coupe (225kW at 5800rpm and 400Nm from just 1300rpm), which was released as the flagship of the all-new E92 3 Series Coupe line-up in October, critics will point out they fail to better the performance of the upcoming M3’s most direct rivals.

The Mercedes-Benz CLK63 AMG coupe musters 354kW and 630Nm from its 6.2-litre V8 and Audi’s brilliant RS4 quattro's 4.2-litre V8 packs an identical 309kW punch as well as 430Nm of torque.

However, the new M3 will be in another league when it comes to power-to-weight ratios and should undercut its German competitors by about 250kg and 350kg respectively. Based on the new E92 coupe, which at 1405kg sheds 15kg in base 323i guise compared to its E46 320Ci predecessor, the M3 will be considerably lighter than the 1650kg RS4 sedan and the corpulent CLK63 AMG (1755kg).

The current M3 weighs 1525kg and its successor’s widespread use of lightweight components means it is unlikely to exceed that.

And although its bespoke exterior design and cutting edge new technology (and the fact that top-shelf six-cylinder 3 Series coupe pricing now stands at $108,500 for the 335i – a big $14,600 up on the 330Ci it replaces here) means the new M3 will carry a higher pricetag than its E46 forebear ($140,000), it will also undercut its opposition on price.

The RS4 sedan carries a $164,500 sticker, while the CLK63 coupe’s asking price is near enough to $200,000. Next year’s all-new Lexus IS-F is also expected to offers stiff performance and pricing competition, the former thanks to a circa-300kW 5.0-litre V8.

BMW has revealed no details of the new transmission that will be mated to the high-revving V8 underneath the M3’s power-domed aluminium bonnet, but expect to see a conventional six-speed manual version to become available first.

This will be followed by either the seven-speed SMG automated manual as seen in the M5/M6 or, in what would be a drastic departure from BMW’s SMG gearbox tradition, a much-speculated VW DSG-style double-clutch robotized manual transmission.

As expected, the M3’s V8 is closely related to the M5’s 5.0-litre V10 and features the same 90-degree cylinder angle, the same 500cc cylinder displacement, the same offset crank pin arrangement (despite the fact the V8’s superior inherent balance doesn’t necessitate it), the same individual throttle butterfly set-up (in this case eight instead of 10) and the same oversquare cylinder proportions, via 92.0mm and 75.2mm bore and stroke dimensions.

Likewise, the all-alloy M3 V8 employs a high 12.0:1 compression ratio, double-VANOS inlet and exhaust valve timing technology, and 35mm and 30.5mm intake and exhaust valve dimensions to deliver a specific power output that also exceeds the impressive 100hp-per-litre mark at 105hp/L.

Weighing in at 202kg (15kg lighter than the current M3’s 252kW/365Nm 3.2-litre straight six), the all-new V8 is claimed to be one of the world’s lightest V8s, and features wet sump lubrication and twin oil pumps to deliver what’s claimed to be reliable lubrication at lateral and longitudinal forces of up to 1.4g.

The new V8 is Euro IV emissions-compliant and comprises a short, forged crankshaft that weighs just 20kg, as well as a fibreglass airbox and air funnels, but its most significant new feature is Brake Energy Regeneration technology, which offers superior off-throttle alternator control to recharge the battery - a system that will filter down to other BMW models.

Read more: BMW's next M3 breaks cover