Quote:
Originally Posted by atomic837
As I still drive my 2009 135i (N54 engine) alongside my 2017 M2 (N55), I have the ability to do direct comparisons.
As it pertains to turbo lag in these cars, when I first picked up my M2, my initial perception was that it had significantly more lag than my 135i. From stomping on the throttle to full thrust, it seemed like a full second. This is irrespective of the driving mode it is in. Point blank, the 135i still feels like it is more eager to get up and go. It taps out in the high RPMs, and the M2 at full boost is a faster car, but the power responsiveness is slower.
Over the past few months something donned on me.... Maybe it's not the turbo lag that I'm feeling between the two cars as much as the raw NA power curve. My hunch is that the N54 engine, off turbo, has far more grunt than the N55 does. The extra grunt of the 135i "covers up" the turbo lag to full boost, providing for a very responsive driving experience, especially around town. Likewise, the M2 and its N55 engine really requires its turbo to make it a formidable engine... So in that initial accelerator press, the lack of its raw NA power is very noticeable to me (comparatively speaking).
Can anyone with experience in these two engines concur? Perhaps someone with both a 1M and an M2? I do recall discussion back in 2010 that the N55 was a bit lacking compared to its predecessor, favoring efficiency over power and responsiveness.
Would be interested to hear educated opinions on this.
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I drove my 2008 135i right up to the arrival of my M2. I am not sure I agree with the assessment that the turbo lag is larger. But part of that would be how you drive, and what RPM you start from when you want to giddy up. My impression was that the N54 had more of a kick in the pants boost typical of a twin turbo, while the N55 was smoother (from the twin-scroll single turbo design) - so you might feel that as lag if you were looking at the rate of power feed at similar rpm. Not sure what the dyno charts look like side by side, but it feels that way to me. I tend to stay above 2000 rpm at cruising speed and above 3K if I am trying to be sporty (and above 4K if... never mind)... so what happens at low rpms does not bother me.
When I want it to giddy up and I am at a decent RPM, it goes... not enough lag to complain about IMHO. It is a turbo though, so it will be laggy if you are slumming in the 1-2K range.
As others have said, drive it like an M car and you will be fine!