BMW M4 CS 2018
BMW M4 CS
The BMW M4 states its case as a compact high-performance coupe, the optional Competition Package gives it an extra edge, and the M4 GTS is an uncompromising sports car also designed for use on the track. And now the new limited-run special-edition BMW M4 CS fills the gap between its BMW M GmbH stablemates. With its eye-catching, emotionally powerful looks, it also raises the profile of the M4 range - and, by extension, the BMW M brand - another notch.
A new model-specific front splitter in exposed carbon fibre defines the face of the new BMW M4 CS, which cuts an unquestionably dominant and dynamic figure even when standing still. The car's athletic lines extend along the CFRP bonnet and powerdome, over the roof - with its shallow central channel - and the new, likewise carbon-fibre spoiler lip on the boot lid, to the rear diffuser and its four exhaust tailpipes, integrated with impeccable stylistic fluency. The shape of the M4 CS appears as if cut from a single mould, underlining the design aspirations of the modern sports coupe.
The extensive use of carbon fibre-reinforced plastic (CFRP) ensures that the new BMW M4 CS is extremely light; indeed, its kerb weight is just 1,580 kilograms (acc. to EU, excl. driver). As well as the rear diffuser, large sections of the body are also made from CFRP. The bonnet, for example, is around 25 per cent lighter than that of the BMW M4 as a result. BMW's many years of experience in the production of carbon-fibre components and carbon fibre-reinforced plastics has paid dividends with the new BMW M4 CS. Indeed, the CFRP roof is more than six kilograms lighter than a conventional metal item. Another benefit of this extremely light and yet highly robust composite material is the corresponding lowering of the car's centre of gravity, which endows the BMW M4 CS with even more agile handling.
Unlike the BMW M4 GTS, BMW has deliberately steered the M4 CS away from a focus on the track. For example, the front splitter is not adjustable and instead of a large, adjustable wing, the rear end sports an exposed-carbon-fibre Gurney - i.e. an aerodynamic spoiler lip running across the trailing edge of the boot lid that significantly reduces rear-axle lift once again compared to the M4 with Competition Package. In the interests of everyday practicality, the M4 CS also forgoes the roll cage fitted in the M4 GTS.
The BMW M4 CS was honed at the Nürburgring Nordschleife, one of the world's most exacting test tracks for high-performance sports cars - proof, if any were needed, that the new BMW M4 CS has been set up to deliver exceptional dynamics as well as unrestricted real-world usability. The M4 CS lapped the 'Ring in 7 min. 38 sec., which ranks it between the BMW M4 and the uncompromisingly track-focused M4 GTS.
The excellent dynamics of the new BMW M4 CS are rooted not only in a fresh round of suspension revisions over the M4 with Competition Package in terms of spring/damper settings, but also in a moderate increase in power for the six-cylinder in-line engine. Fitted in the M4 CS, it develops 460 hp - that's 10 hp more than in the M4 with Competition Package. Peak torque increases by 50 Nm (37 lb-ft) to 600 Nm (442 lb-ft).
Generous use of Alcantara and leather has allowed the development engineers and designers at BMW M GmbH to conjure up an interior with an enviable sporting feel. Paring down the passenger compartment to the essentials and, in so doing, achieving significant weight savings was also the declared aim with the interior door panels and the side trim in the rear compartment. Both are made from compacted natural fibres - renewable raw materials, in other words - and have been given a special carbon-fibre look. Conventional door pulls give way to lightweight loops in the BMW M4 CS. And yet, despite the rigorously sporty mindset embodied by its cabin and also expressed in the presence of lightweight M sports seats, passengers in the BMW M4 CS need not go without niceties such as single-zone automatic climate control and a high-quality, specially adapted version of the HiFi System Professional.
A sensational straight-six engine
The six-cylinder in-line engine has a great tradition at BMW, and in the new BMW M4 CS it is once again responsible for delivering performance par excellence. When compared to the M4 with Competition Package, maximum output has been increased by ten horsepower to 460 hp, which is on tap at 6,250 rpm. Peak torque of 600 Newton metres (442 lb-ft) is a whole ten per cent higher (M4 with Competition Package: 550 Nm / 405 lb-ft) and can be summoned up over a very wide rev range - from 4,000 rpm up to 5,380 rpm. These power reserves endow the new BMW M4 CS with supercar-like performance. The 0 to 100 km/h (62 mph) sprint is over in a breathtaking 3.9 seconds, for example. The top speed of the BMW M4 CS, which comes with the M Driver's Package as standard, is electronically limited to 280 km/h (174 mph).
The high power output of the 3.0-litre engine can be attributed to its free-revving design, as well as the inclusion of two turbochargers and extremely effective charge air cooling. The M TwinPower Turbo technology at work in the BMW M4 CS employs two very responsive mono-scroll turbochargers, which combine with High Precision Injection, VALVETRONIC variable valve timing and Double-VANOS fully variable camshaft control to ensure the six-cylinder unit can deliver its power to maximum effect. Charge pressure is built up continuously from just above idling speed, while the fully variable valve and camshaft timing helps to maintain a high efficiency factor. This not only enables the engine to generate its power continuously over a very wide rev band, it can do so very economically, too. Fuel consumption and therefore exhaust emissions remain low (fuel consumption combined: 8.4 l/100 km* [33.6 mpg imp]; CO2 emissions combined: 197 g/km*). The high-revving ability of this exceptionally refined six-cylinder unit likewise benefits from VALVETRONIC and Double-VANOS technology. As a result, the straight-six under the bonnet of the BMW M4 CS has an impressively high rated engine speed for a twin-turbocharged unit of 7,600 rpm.
Thanks to its closed-deck design, the six-cylinder engine's crankcase is remarkably rigid, paving the way for high cylinder pressures and very effective power output. The sleeveless cylinder walls, with their twin-wire, arc-sprayed coating, help to save weight. Another feature designed for top performance is the forged crankshaft boasting a lightweight design yet also high torsional strength. This keeps the rotating mass low and thereby makes the twin-turbo power unit even quicker to respond.
The engine's oil supply system is another technical highlight, while also showcasing the vast motor sport expertise of BMW M GmbH. It has been designed with the tough demands of track racing in mind and makes sure the six-cylinder in-line engine is kept supplied with lubricant at longitudinal and lateral forces of up to 1.4 g. The lightweight magnesium oil sump is fitted with an additional cover to limit the lubricant's surging movements, even during extreme driving manoeuvres such as abrupt changes of direction on a race track. An extra oil suction pump combines with a highly effective oil return system to ensure an unfailing supply of oil, even when performing extreme braking manoeuvres.
It goes without saying that an M power unit must come with the acoustics to match. In the new M4 CS, this is the task of a dual-branch sports exhaust system with a total of four tailpipes, which are neatly incorporated into the styling of the rear diffuser. Its exhaust back-pressure is as low as possible, something which is conducive to power build-up, and it is governed by a system of flaps. Positioned directly upstream from the rear silencers, the flaps are controlled electrically and are designed to provide optimum feedback on the engine's load state throughout the entire rev range as well as generating that unmistakable, sporty M sound. The driver can alter the way in which the system of flaps works by preselecting a driving mode.
Power is transmitted to the rear wheels of the new BMW M4 CS via the seven-speed M Double-Clutch Transmission (M DCT) with Drivelogic that has already been successfully used in the M4 and M4 GTS models. The extremely fast gear changes mean there is no interruption in power flow, while the M Launch Control function ensures flawless acceleration from a standing start. The M DCT unit operates fully automatically, but there are also shift paddles on the steering wheel for changing gear manually. In order to cope comfortably with even the most demanding operating conditions, the seven-speed transmission comes with a dedicated oil cooler.