Originally Posted by Uli_HH
If the rumor about an N55 engine in the M3/M4 is right, than thats are very bad news ... because that would be an decision only about cost issues ... and this meen the engine had to be as cheap as possible - that meen as much as common parts with the AG N55 as possible.
All you need to bring the N55 into the needed hp-numbers is to re-inforce the engine-block and crank-shaft-housing to withstand the higher pressure of an bigger turbossystem, that is needed to reach the hp-numbers. So they would simply put struts on the outstide of the crank-shaft-housing of the N55 to make it stronger ... and then add an turbo big enough to reach the 450hp margin ... this could be an single big TwinScroll-Turbo, two Standard-Turbos or an modified N57-S TriTurbosystem ... I would put my money on the first or the third alternative, because an BiTurbo on an I6 donīt allow the use of BMW favored TwinScroll-Turbosystem. And to reduce the big lag of such an big turbo BMW would use the patented eTurbo-System to drive the turbos at low rpm ... to create an N/A feeling.
This is simply the cheapest way to make an I6 turbo engine with ~450hp and probably the way BMW (not the M-GmbH!) decided to go ... if Scotts Infos are right ... and only marketing would quotes this as an heavily modified N55.
But for me ... "heavily modified" meens, that only the pure engine block layout comes from an standard AG-engine and all other parts are unique to the M-engine ... like it was the case with all M-GmbH engines before the totally unique S85/S65 engines.
P.S. ... but I have still some hope, that Scott isnīt right in this case and we get again an totally unique M engine in the F8x ... I know an new statement from an internal that we shouldnīt be afraid of the engine and that the current opinion in the internet and statements of an BMW US-official are not right.
I dont know what everyone is so suprised about, this is EXACTLY what BMW did with the new M5 and M6, so why is it a shock that they are using an existing block as the basis for the 'new' engine? If they did it for the top of the line M, no reason not to accept that the M3/M4 get to follow the same path, makes perfect sense in the new world of bmw