Quote:
Originally Posted by newBMWownr
I'll be curious to see how they address the questions of NVH. The small displacement (relatively speaking for a modern 4 cylinder engine) should keep second-order shaking forces in check and I would be stunned if the engine didn't incorporate balance shafts. Other hopeful items would be magnetorheologic engine mounts (manufactured by Delphi and used by Porsche) that allow for changes in durometer based on engine speed. BMW also was very proud of the acoustics on the magnesium/aluminum block so perhaps some of that technology will make its way to the turbo 4. I would expect that the block in general will be very stiff and have a deep skirt design, as the N55 does, which will also control unintended NVH. Valvetronic and the lack of a throttle plate in the intake tract should allow them to tune induction noise in ways that make it sound pleasing to the ears. If not, perhaps electronic noise suppression (as Acura does) might allow for the tuning of undesirable frequencies.
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Well, a couple of things. Yes BMW could pull out all the stops and throw in twin balance shafts running at twice crank speed, active motor mounts, active noise cancellation, and whatever other gizmos they can think up to actually make this thing run like a BMW should, but guess what? Then they'll depending on a whole lot of tech toys and gizmos all to cover for an inferior (for a premium vehicle) engine configuration, and the same sorts of gizmos that BMW and the Germans generally don't have a good reputation for building reliably. Even Honda had issues with their active noise cancellation systems in the Honda Accord Hybrid a few years back, which covered up the weird noises that a V-6 engine running in 3-cylinder mode made. When the systems started to not work, it resulted in a lot of funny noises in the cabin which annoyed owners and Honda was clueless as to how to fix. Lots of people traded the car in, and Honda discontinued the model. I'd rather just have the straight-6 which doesn't need any of this crap.
Let's say BMW does get it completely right though and there's no issues at all with a brand new engine design and "active" noise cancellation and balancing systems (on a 1st year BMW design? heh...). It's still probably going to drive a whole lot different than an NA I-6 will. If you happen to like the driving characteristics of the N52, this is going to be a lot different. They'll probably use the low-RPM torque capabilities of the engine and gear it down so that you're never really breaking 3000rpm. It maximizes load on the engine, increases combustion efficiency and minimizes friction, and keeping the average RPM down will also reduce the NVH it'll be making. It most likely will NOT be the free-revving nicely sounding and singing style of power delivery that many love and the N52 delivers.