Originally Posted by bimmerjph
The N55 isn't that old. It came out for the 2011 model year I believe.
There are a few reasons why they aren't using the S54 anymore. One is that the is literally nothing left to be done to that engine. BMW got nearly everything that engine has to offer. It was the ultimate iteration of the M52* (which came out in 94) based engines. And the second is that it isn't as efficient (fuel wise) as the N55.
But yeah I do agree with you BMW has taken this efficiency thing a bit too far IMHO.
*Yes I meant M52. The difference between the M52TU and the M54 consists of a slightly different intake manifold shape, a slightly tweaked exhaust manifold, and it switched to an electronic throttle control. So the M54 is very very very similar to the M52.
If BMW were
to use the N55, I hope it is a helleva lot stronger than the one that I have in my 2011 135.
Coming from the N54 in my 2008 135, there is a noticeable difference in the pulling power of those two motors. honestly, the N54 just kept wanting to go...and the N55 just...doesn't.
Not saying they can't make it a beast for the new M3/M4, but in my mind there will have to be significant upgrades. It just doesn't seem to be on the same level as the N54...
This is all based on the presumption that there will not be a bespoked ///M engine, which would obviously eliminate those concerns...
Current - 2011 N55/DCT E82 135i--Lemans Blue, Gray Leather, M Sport, Premium
Past BMWs: 2008 E82 135 - AW, N54, MT
2007 E92 328 - JB, N52, MT, ZSP (traded in for 135)
2007 E92 328 - JB, N52, MT (retired by a drunk driver)