BMW M4, Porsche 911 Carrera S Comparative test: Can the M4 outperform the 911?
With its new 550 Nm biturbo six-cylinder engine, the BMW M4 aims to out-accelerate the Porsche 911 Carrera S. But can it also stay out in front in the corners?
At some point every car enthusiast dreams of owning a Porsche 911. However, not many can fulfil this dream. The rubbish thing about it: affordable alternatives are rare. But they do exist. For example, in the form of the BMW M4. Granted, it too is far from cheap; but it still costs more than 30,000 Euros less than a Porsche Carrera S – this is equivalent to the cost of a VW Golf GTI Performance.
The BMW M4 produces 431 bhp
And the BMW M4 ticks all of the boxes when it comes to holding its own against a 911: 431 bhp, 550 Nm of torque, alongside the chassis expertise of M GmbH, which is even highly esteemed by the Porsche engineers themselves. And it is precisely the latter that we now want to try out for ourselves.
Press on the start button in the BMW M4. The biturbo inline six-cylinder engine barks, almost like a racing engine – astonishingly raw when it comes to tone. The three-litre engine originally came from the 435i, but has received a general overhaul: cylinder head, crank case, connecting rod, pistons, crank shaft - all new. And of course two turbo chargers instead of one. In conjunction with the replaced manifolds and the stand-alone exhaust system, this results in an unusual six-cylinder tone.
What a shame that the sound doesn't really carry to the interior of the BMW M4. On the other hand, the outside world is practically bathed in sound waves. The three-litre engine snarls like a box engine, then nags like a 180-degree V8, before then releasing a fanfare of sound into the sky. The only complaint is that more of this should reach the driver's ear rather than dissipating into the environment.
The three-litre engine has plenty of thrust. Of course both of the BMW M4's turbo chargers have to get going first. However, even in the suction range, the chunky inline six-cylinder engine lets rip, the transition is smooth and results in vehement forward thrust at up to 7,300rpm. In addition, the seven-speed dual clutch transmission (3,900 Euros) always has the suitable drive position available. In the Sport plus position responds too heavily to the accelerator pedal – in city traffic it takes a lot of sensitivity to avoid jerking. And: If you switch to position three in the transmission settings, you'll have to live with rather leisurely gearing down.
BMW M4 in M2 mode in Hockenheim
However, we are now in Hockenheim on the short circuit and have carefully configured the BMW M4. There are two useful buttons on the steering wheel, M1 and M2, which can be freely assigned. Author's recommendation for the country road (M1): set the shock-absorbers to Comfort for the best traction, ESP to Sport mode for a slightly longer line, and set both the engine and steering to Sport also.
M2 comes in useful in the BMW M4 in Hockenheim: shock absorbers and engine to Sport plus, steering to Sport, and ESP off. This requires sensitivity on the accelerator, but produces the best result – otherwise the electronics are frequently called on to keep the 550 Nm in check.
The BMW M4 drives itself along the home straight, finally showing just under 200 km/h on the speedo. Hard braking: The front axle, already heavily laden by the engine, receives even more pressure – and the rear axle is relieved. The ABS intervenes, strong and long, to guarantee longitudinal stability. This affects the deceleration, as the evaluation of the measurements will shoe.
The BMW M4 requires sensitivity on the accelerator
Northern curve: the front tyres wail. If you steer into the corner too late, you will overrun – resulting in understeer until leaving the corner. So take it slower into the corner, and faster out. However, it is worthwhile making moderate use of the 550 Nm here, as otherwise the rear axle will kick out. If you take your foot off the gas, and it bites back relatively abruptly, which requires quick countersteer – or you can stabilise the car into a slight drift using the accelerator, although this affects the lap time. It takes a while to get into the BMW M4 groove and get to know the car's idiosyncrasies in Hockenheim. After a perfect lap, the stopwatch reads 1:13.6.
Can this undercut the Porsche? The Carrera S is fast, very fast. This much it has already proven to auto motor and sport many a time. However, the reputation as THE German sports car is very much its to lose. Is this piece of engineering, in which an in itself antiquated drive concept has been continually refined over generations, still able to compete? The dual begins with the acceleration test. Its wave of torque drives the 154 kilogram heavier BMW M4 to a speed of 100 two tenths faster. Revenge in the drive dynamics test: in the 18-metre slalom the lighter 911 has the advantage. The rear of the vehicle, which steers with you more when cornering, weaves through the cones with a touch more agility. The difference in the brakes is more pronounced. Here the heavy box engine behind the rear axle proves to be of advantage: it exerts pressure on the tail and the rear wheels can transfer greater braking power.Command and execution
The decision must be made in Hockenheim. The first surprise on the short circuit right from the start everything falls into place much more quickly in the Porsche 911. You only need one lap to accustom yourself, and then you can push it to the limit. Second surprise: the Porsche feels an entire vehicle class smaller than the BMW M4. It is in fact just two centimetres narrower – it is all a matter of feeling. The Carrera S communicates more directly: it implements commands more quickly and reports back more accurately. Third surprise: unlike in the M4, there is no understeer. Even when cornering on the brakes, the 911 gently pushes with the rear, positioning itself perfectly.No understeer in the Porsche 911
How things go from here is down to personal driving style. If you gently, but continually press down on the accelerator, the Porsche will carve wonderfully neutrally around the apex of the corner and can achieve a time of 1:11.8 min, thus faster than the BMW M4. If you lift off and then vigorously demand power, the rear-wheel drive sports car will drift smoothly around the corner . A little slower, granted, but it's also more fun – a 911 has never been so simple to drift.
Whether a basic Carrera S would corner just as briskly and decelerate so stably even after several laps is debatable. For the test car in Hockenheim is aided by drive dynamics options such as the sports chassis including anti-roll compensation (4,034 Euros) and ceramic brakes (8,509 Euros). This is added to the base price of 105,173 Euros, including the dual clutch transmission for 3,511 Euros. Yet in the end even the much poorer price-performance ratio does not prevent a narrow victory over the BMW M4, by a single point.
Date16 February 2015