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Join Date: Feb 2008
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BMW M3 and M4 unveiled
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The BMW M3 is back, faster and more powerful than ever. But this time around it can only be had as a sedan, and with turbocharged six-cylinder power for the very first time in a move that dispenses with a distinguished quarter century of BMW M division tradition of placing high revving naturally aspirated engines into its iconic 3-Series-based performance model.
- New 317kW six-cylinder turbocharged engine
Pictured here in production car guise for the first time, the new 317kW four-door M3 sedan will be joined from the outset of sales in 2014 by its sister model, the sleeker M4 coupe - a mechanically identical two-door previewed in lightly veiled concept car guise at the Pebble Beach concourse in California earlier this year.
The new BMW M3 sedan and BMW M4 coupe are planned to make their public debut at the Detroit motor show in early January prior to the start of Australian sales during the latter half of 2014. Prices are yet to be announced, though officials have signaled they are likely to rise over predecessor models in line with what BMW describes as added performance potential and greater equipment levels.
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At the heart of BMW’s latest M3 and its more sporting M4 sibling is a brand new twin-turbocharged in-line six-cylinder direct injection petrol engine. The 3.0-litre unit is based around the German car maker’s familiar N55 engine with 84.0mm bore and 89.6mm stroke measurements, although such are the changes to the aluminium block, cylinder head, induction and exhaust systems and internal architecture that BMW’s M division describes it as being all-new.
Among the developments BMW’s M division is talking up ahead of the public debut for the M3 sedan and M4 coupe next month is the engine’s patented induction process known under the title M TwinPower Turbo. It eschews the twin scroll principle of BMW’s regular engines for a system that uses two low inertia turbochargers running a maximum 1.3 bar of boost pressure and fed by a compact water-to-air intercooler system mounted atop the engine. Weight saving features such as a magnesium sump sees the new engine tip the scales 10kg under that of its predecessor at a claimed 205kg.
With 317kW developed on a band of revs between 5500 and 7300rpm and 550Nm of torque between 1850 and 5500rpm, the blown six-cylinder delivers 8kW and 150Nm more than the naturally-aspirated 4.0-litre V8 mill it succeeds. An impressive 106kW per litre – some 29kW more than its predecessor through the effects of forced induction and other efficiency gains, also endows it with the highest specific output of any series production M division engine to date.
With familiar M division technology such as Valvetronic variable valve timing and Double VANOS continuously variable camshaft timing, the new six-cylinder revs to 7600rpm – 600rpm less than the V8 it replaces. But with its peak torque delivered 2050rpm earlier, BMW claims the new unit delivers far greater flexibility across a wider range of revs.
While billed as the most powerful series production engine to find its way into the M3, the new in-line six-cylinder, codenamed S55 B30, is the smallest capacity engine to be used by BMW’s M division since the discontinuation of the first-generation M3 and its naturally aspirated 2.3-litre four-cylinder powerplant, the S14 B23, back in 1991.
In combination with BMW’s efforts to pare weight from its new performance car duo, including the use of carbon fibre reinforced plastic and other lightweight materials, the added reserves help improve the weight to weight ratio of the M3 sedan and M4 coupe over their respective predecessors by 2.0kg per kilowatt, with both boasting 4.8kg per kilogram. By comparison, the latest Porsche 911 Carrera S boasts 4.7kg per kilowatt.
Channeling the drive to the rear wheels is a standard six-speed manual gearbox. The Getrag-produced unit has been developed from scratch and is claimed to be a 12kg lighter than the unit used in the outgoing fifth-generation M3. Among its innovations is dry sump lubrication, a double plate clutch to handle the added torque loading, carbon-ceramic friction linings within the synchroniser rings and a blip function on downshifts. The individual ratios are also shorter than before, with the final drive dropping from a previous 3.85:1 to 3.46:1 for added pace off the line.
Buyers will also be able to choose an optional seven-speed M Double Clutch Transmission (DTC), again from Getrag, with remote paddle shifters. A development of the unit used in the M5, it allows the driver to choose between manual or automatic modes. Further features include launch control and a so-called smoky burnout program – the latter permitting a degree of wheel spin while the car is travelling at low speeds. To help improve on-the-limit handling, it also receives stability clutch control, which opens the clutches when sensors detect understeer (or front-end push) to reduce drive and bring it back on line.
Both gearboxes receive an automatic stop/start function, together with brake energy regeneration and optimum shift indicator. Despite BMW’s earlier claims that the DTC unit is just 20kg heavier than the manual gearbox, the official weight figures reveal it comes with a 40kg penalty over the manual.
In a new driveline development, the new M3 and M4 adopt a carbon fibre reinforced plastic propshaft. Constructed as a single component with no centre bearing, it is claimed to bring a 40 per cent weight saving on the previous M3’s steel driveshaft while providing a reduction in rotating masses for improved driveline efficiency.
The new driveshaft is allied to hollow output shafts at the rear within the Active M differential, which continues to use an electronically controlled multi plate clutch to provide a varying degree of lock up between 0 and 100 per cent depending on prevailing traction.
With an official 0-100km/h time of 4.3sec in standard six-speed manual guise, the new M3 and M4 are not only a significant 0.5sec quicker than their respective predecessors to the traditional benchmark but they also match the time quoted for the more powerful M5, which receives a seven-speed dual clutch gearbox as standard. With their optional seven-speed dual clutch gearbox on board, their 0-100km/h time drops to an official 4.1sec, quicker even than the M6.
BMW also says the new M3 and M4 will run the standing kilometer – now an essential figure in performance claims among Germany’s performance car elite – in 22.2sec. As with all BMW M division models, top speed is limited to 250km/h. An optional M Driver’s Package raises it to limited 280km/h.
The improvement in straight line performance is combined with a dramatic improvement in fuel economy. Official figures point to a combined cycle average of 8.8L/100km in manual guise and 8.3L/100km with the DTC gearbox – figures that point to respective CO2 emissions of 204g/km and 194g/km. The previous M3 sedan and M3 Coupe boasted figures of 12.4L/100km in manual and 11.2L/100km in DTC forms, for CO2 figures of 290g/km and 263g/km respectively.
The exterior styling changes over the 3- and 4-Series have largely been driven by the need to provide the engine bay with added cooling capacity as well as accommodate a widened chassis. The most significant visual modifications are centred around the front bumper, which receives an edgier design and three large ducts – the outer units boasting BMW’s so-called air curtains for more efficient channeling of air.
Further alterations are directed at the bonnet, which receives a characteristic power dome to better accommodate the engine and provide adequate pedestrian crash protection, and the front fenders, which are more heavily fared and adopt an air breather to extract hot air out of the engine bay.
Further back, there are new two-tone exterior mirror housings and more substantial sills underneath the doors, while the rear receives widened fenders to house rear wheels that are wider in than those of predecessor models as well as a re-profiled bumper with integrated vents to extact hot air from the rear differential and BMW M division’s signature quad-tailpipe treatment.
In a continuation of earlier efforts to shed weight from its performance orientated M division models, BMW has provided both the M3 sedan and M4 coupe with a carbon fibre reinforced plastic (CFRP) roof panel for a reduction of 5kg and 6kg respectively. The bonnet and front panels on each car are fashioned from aluminium. According to official figures, the M3 sedan as dropped 85kg over its four-door predecessor at 1520kg in manual guise, while the similar specified M4 coupe is 83kg lighter than the old M3 coupe at 1497kg.
The reduction in weight is significant given that both of BMW’s new M cars have grown in dimensions; the M3 sedan, codenamed F80, is 91mm longer, 70mm wider and 23mm higher than before, while the M4 coupe, known internally as the F82, gains 56mm in length and 65mm in width but is 42mm lower than the outgoing fourth-generation M3 coupe.
While they rely on the same basic high-strength steel platform structure as the standard 3- and 4-series, the new M3 and M4 receive a largely bespoke chassis with reduced ride height and noticeably wider tracks, which have increased by 34mm up front and 18mm at the rear to 1579mm and 1603mm respectively to provide BMW’s latest in a long line of illustrious M cars with a truly sporting stance.
The suspension, a traditional MacPherson strut (front) and multi-link (rear) system, has also been extensively reworked, with lightweight components and new mounting processes claimed to have reduced unsprung masses and significantly boosted rigidity over the outgoing M3.
Key changes include the adoption of substantial carbon fibre strut brace, aluminium control arms, wheel carries and sub-frames up front, bringing about a 5kg reduction in weight. The rear has also been extensively revised with aluminium control arms and wheel carries and an axle that is bolted directly to body without the use of rubber bushings, shaving 3kg off the weight.
“Mounting for the rear differential within the rear axle subframe, which is bolted to the body structure, has allowed us to achieve a new level of handling precision, but without neglecting comfort,” says Albert Biermann, BMW M division development boss, of the new cars.
The suspension supports standard 18-inch wheels – 9 inches wide up front and 10 inches wide at the rear. They come shod shod with 255/40 profile front and 275/40 profile rear tyres. Buyers can also choose optional 19-inch wheels with the same profile rubber.
An optional Adaptive M Suspension brings variable damping control in three different modes: Comfort, Sport and Sport Plus – each of which boasts its own individual stability control calibration.
In line with standard 3- and 4-series models, the new M3 and M4 also receive an electro-mechanical steering system with a ServoTronic function that adjust the level of assistance according to speed. Developed in partnership with ZF, it also offers the driver of the choice of three modes at the touch of a button: Comfort, Sport and Sport Plus.
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http://theage.drive.com.au/motor-new...212-2z77p.html
And the M3 and M4 look HAWT!!!! yes please
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