Originally Posted by Uli_HH
SORRY ... but I donīt beleave that the redline of the S55(?) would be higher than the S63Tü redline ... and 7.500rpm no way !!!
If they choose the V6 I think 7.500rpm redline were an good target ... but with an N55 like I6 with its long stroke and its long crank its simply too costly by materials to reach this target.
I think we could be happy if they reach 7.000rpm ... and also this I donīt rally beleave.
Let's look at piston speeds. US units, sorry Uli...
N55: 68.6 ft/s
S65: 69.1 ft/s
S63Tu: 70.1 ft/s
Thus non-stroked S55(?) at 7500 rpm: 73.5 ft/s
Stroked S55(?) to 3.2l at 7500 rpm: 78.4 ft/s
Ferrari 458: 79.7 ft/s
I know, I know don't compare BMW and Ferrari. That complaint falls flat though when looking at the S65, it is the closest to a Ferrari engine in any other production car.
From this I think it is fair to say that even a stroked 3.2l S55(?) could support a redline of 7500 rpm.
Of course there is the question of Valvetronic and its rpm limit. I've only heard rumors about that.