Old thread I know, but I just wanted to comment on the N55 in my 335i.
I had a 135i with N54 right before I picked up my 335i Msport.
The N54 typically dyno'd with a bit more HP than the N55.
Having driven my 335i now for about 1400 miles, I am simply amazed at how much power this engine produces.
It also feels like big torque comes at a bit less rpm.
The really amazing part is that my 335i feels stronger/more powerful than my 135i N54 did. I have no dyno to back that up, just driving experience.
There is a long country road near my home where I have marked off a 1/4 mile. Take off in the 335i feels stronger, and by the end of the 1/4 my trap speed is at least 5mph higher than what I could get with my 135i.
The 135i is also a bit lighter than my 335i by 337lbs. That's a substantial weight difference.
The 135i was a MT and my 335i is sport AT.
Even to match the acceleration of the 135i my 335i has to be putting out more power. To beat it, it has to put out more still.
I bring this up because I'm thinking BMW upped the power in the newest N55, and may be waiting to make an official announcement about it when the new coupes arrive.
Other than that my 135i must have been a weak example of an N54 and my N55 must be an exceptional example.
Just to cover/match the 337lbs difference there has to be about
30hp/30lb ft more power. The sport AT isn't going to account for the higher trap speed, trap speed is about power output.
Anyway, this is all anecdotal. I'd love to see some dyno's from new 2013
335i's, just to see if there is something going on.