Originally Posted by ovekvam
But the M54B30 is not really relevant as comparison to the N13B16, as it has no turbo. The two engines have very different characteristics. The 116i feels almost like a diesel engine with its strong bottom end and lack of power at high RPM.
It is still strange to me that you think the diesel four feels like a superior engine under 4000 RPM. The sound and smoothness (and even smell) of the six is far superior in my opinion. It lacks the torque peak, but you can easily compensate by downshifting once or twice, and have plenty of power availabe. And of course glorious sound as well. Of course that will affect the fuel consumption, but in that case it is not down to which engine feels better, but which engine is cheapest to run. For me it is easy: Petrol feels superior, but is more expensive.
I am pretty sure the M54 is stronger than the diesel at really low RPM as well, like 800-1100.
If you go for some occational weekend fun on a trackday, you will use the RPM range all the way to the redline, and I am 100 percent sure that the M54B30 would put a bigger smile on your face than the diesel four.
The 116i is a rather boring engine that does not come close to the M54B30 in smoothness or sound or power. It does however run quite cheap, and it has practical low end grunt compared to the rather moderate power output. Compared to a 118d, the 116i will feel weak and slow in everyday traffic, but they have similar performance when pushed to the redline.
What you state is all correct. But the lack of low end torque and the high consumption are not compensated by the refinement and sound of the N54. The 116i will have its grunt lower, but not as much as the 118d, but the sound will not be much better either. So, really no competition: 118d every day.
The rare occasions you get on the circuit or the Nordschleiffe, will not be more thrilling with the 116i than the 118d. Than a 125i or M135i are what you need.