View Single Post
      11-17-2011, 10:38 AM   #77
Uli_HH
Lieutenant
Uli_HH's Avatar
Germany
32
Rep
572
Posts

 
Drives: AW M3 E90)/ 523i Touring
Join Date: Nov 2005
Location: Hamburg Germany

iTrader: (0)

Nice to read ... to understand why the M3/M4 engine was choosen:

"What do you get when you take an inline six, fold it in half, and then spread the cylinder heads? I’ll give you a hint: it rhymes with “G-Fix.” A wave of speculation has risen in recent weeks, leaving many to believe that the next generation M3 will feature a V6 engine. Today, Opposite Lock takes a look at the controversy – and takes a controversial stand.

Like double-round headlamps, kidney grills, and Hofmeister kinks – inline six engines are synonymous with the brand. In fact, while BMW has long made V8s, V12s, and inline 4s – the inline 6 has always held a romantic office. Like the famed boxer twins of Motorrad, inline sixes are what first come to mind when looking at the elongated hoods of BMW cars. At a spiritual level, these engines are inseparable from the roundel.

It comes as no surprise then, that the BMW loyal are losing sleep over rumored V6 engines finding shelter under the hoods of future BMWs. The M3 is in many ways a halo car for the brand – so opening its hood to find a V6 underneath represents the greatest departure from tradition that BMW could possibly mount.

I am a traditionalist to the core, and trust me, it pains me to see the demise of the inline 6 M3. Of course, this pain has faded somewhat over the last 6 years wherein the M3 has been powered by a V8 – and a fabulous V8, mind you. Couple that with the fact that the first M3 featured an inline 4, and suddenly I6 reverence can seem a little unfounded – at least when it comes to what’s powering the M3.

Form must follow function. This doesn’t just apply to aero. To push the boundaries of what is possible (read: progress) and to achieve new possibilities through engineering, sometimes changes come as revolutions – not evolutions. There are many benefits to developing a V6 unit, and they must be weighed against the benefits of inline 6 design. “Form follows function” is a mantra I hold very close to my heart. It’s why I donned a dorky swim cap when contesting a triathlon. It’s why I insist on loading the toilet paper roll with the paper falling to the outside, not the inside of the dispenser. It’s also why I reserve a special hatred for fake air intakes used for aesthetic purposes only. If a design offends tradition but enhances function – all the power to it. “Bring it on,” I say.

The inline 6 engine layout is inherently the most balanced configuration possible, with reciprocating masses nicely cancelled out. These engines truly are, “silky smooth.” For this reason, they have long been chosen for large commercial applications, for example, most highway semi-trucks feature large diesel inline sixes. Naturally, in performance applications, this also lends itself to higher rev capabilities before grenading. The biggest draw back in the context of performance would be the length and height of an inline 6 engine. Obviously, standing the cylinders up vertically, and in the longest line possible, is not conducive to a low center of gravity, nor is it conducive to enhancing the front to rear weight bias of the car.

The V6 engine layout is not one of prestige – but it is one of function, particularly if coupled with BMW’s new cross-bank cylinder manifold technology. As in the S63 M engine, the turbos would be housed within the ‘V’ of the cylinder banks, thus making the engine incredibly compact. The blades of the turbines would be placed very close to the exhaust valves, thus decreasing lag. Also of benefit, the engine becomes slightly squatter with a lower center of gravity, and nearly half the length of the block can be eliminated, lending to better weight distribution and more nimble handling.

There are two paths to take with the V6 engine, utilizing either a more balanced 60 degree angle – allowing a 120 degree firing order – or utilizing the much rougher 90 degree design, which both feels, and sounds, less refined. The problem I see with BMW utilizing a 60 degree V design, is that it may not allow enough room to house the turbos within the V-bank. This could largely undo the argument for V6 implementation, since it likely hinges on the capitalization of a similar plumbing layout to the S63 V8 unit. Rumor has it that the M division has thus far been unable to smooth out the V6 concept engine to an acceptable level, and this also hints at a 90 degree V bank starting point. Of course, the biggest improvement expected from a turbo charged V6 design would come in the name of efficiency – with a likely target of a 30% decrease in fuel consumption. If the new M3 can offer increased performance with significantly less consumption and pollution, a good case will have been made for the controversial move to a V6.

On the topic of prestige, Formula 1 will be adopting turbo charged V6 engines in 2014. When it comes to engineering prestige, it’s tough to top the glamor of F1. An added benefit to V6 engines is found in that this configuration allows the engine to remain a stressed member – useful in such extreme performance applications.

Many among us still bemoan the move from high-rev naturally aspirated engines to the turbo units of today – and tomorrow. Those of us who have recently experienced the best BMW has to offer on the table of M design, however, are looking on the bright side. No, the new S63tu, as found in the F10 M5, does not rev to the stratosphere – and I lament this fact. But it does have a powerband spread from Monday to Sunday – and so much torque at the ready that the M5 is constantly fighting for grip. It is a magnificent car, and it is special because of its turbo engine – not despite it. The case in point: sometimes, progress is disguised as heresy, and embracing it – though difficult at first – is thrilling.

At this point, only a few well placed individuals know the fate of the next M3′s engine design. Should it be a V6 when finally released, I for one will not be found sitting on my couch sulking. I will more likely be found sitting behind the wheel, counter steering through a corner. Revolution can be a lot of fun, after all." (found on motor blog)

Last edited by Uli_HH; 11-18-2011 at 05:35 AM.