Quote:
Originally Posted by bradleyland
There's a much simpler explanation.
Engineering, as much as any other field, tends to develop a set of beliefs that are shared amongst the majority of people working in the field. Currently, one of these beliefs is that 500cc is the optimal cylinder size for efficiency. This belief is held in high regard at BMW. If you watch many of BMW's marketing videos, you'll hear engineering spokespeople mention it this magic number.
What do you get when you multiply 500 by 6? You get 3,000, which is the displacement of most BMW designed I6 engines.
What do you get when you multiply 500 by 8? You get 4,000, which is the displacement of the S65.
What do you get when you multiply 500 by 10? You get 5,000, which is the displacement of the S85.
The simplest explanation is most often the correct one. No conspiracies required to explain this one.
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The video explains
how the 500cc/cylinder came to be standardized across BMW's lineup as a
modular engine platform.
As to
why this is the case, of course BMW will tell you this is the best way to build efficient engines. Like you said yourself, it was a marketing video.
While there may be some engineering truth to that number of 500cc, economics is the underlying reason.
1)
Platform sharing
Application: This 500cc cylinder will share not only the same displacement, but the same bore/stroke, compression, piston, rings, etc.
The same cylinder architecture will be used across all engine configurations (inline-3, inline-4, inline-6, etc.) in modern BMW engines beginning with the B-series B37, B38, B47, B48, B58, etc.
Economics: BMW Group only needs one cylinder design (and various components only need to be designed once), which significantly reduces R&D costs, as well as increase efficiency in manufacturing, logistics, and parts availability. Consequently, this allows BMW to continue to expand on its product portfolio through parts sharing. This minimizes costs/increases profits, increases interchangeability of parts (minimizing lead times), reduces the need for special training and tooling for different engines (reduced labor/manufacturing costs), and enhances efficiency as a result.
1b) The S65 and S85 are unrelated to modular platform. While they share the 500cc/cylinder concept, the cylinder architecture is not the same as the new modular platform. In fact, the only engines the S65 and S85 are related to are to each other.
2)
Expanding Market Share
Taxation: BMW increasingly wants to target emerging markets across the world. In many markets outside of the US, vehicles are taxed based on engine displacement. For example, in mainland China, 3000cc represents quite a magical number, in that any engine larger than 3.0L is subject to a much higher tax.
China has already overtaken the US as the largest automobile market.
There is a high demand for [relatively] lower displacement vehicles, specifically engines under 3000cc where there is a significantly higher tax for engines exceeding that size. The modular platform with 500cc as a base allows flexibility in engine design and applications that will fall perfectly within tax brackets of various jurisdictions across all markets while reducing tradition limitations in manufacturing different size engines. BMW would no-longer have a problem manufacturing different size engines (in multiples of 500cc) since, as mentioned above, the parts and R&D sharing from this platform allows for quick, logistically sound, and cost-efficient manufacturing processes that increases BMW's ability to pump out engines of various cylinder counts simultaneously and at a high volume.
Quote:
Originally Posted by tallshortguy
They care about awards but they will not plan product development around the fact that they're "afraid" to compete with other companies engines. I highly doubt BMW doubts their ability to compete with any engine maker.
Besides that BMW had already stated before the S55 that they found .5liters/cylinder to be the most best configuration balancing performance and efficiency.
It's silly to suggest BMW engineers and design leads purposely didn't make the S55 a 3.2, 3.4, etc. liter engine because they were afraid of competing against McLaren's 3.8 V8 in a single category of an awards program.
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BMW doesn't design its engines or cars specifically to win awards, but the awards do matter.
Still, there is a reason BMW has stuck with 3.0L. The number is not an accident of history. It is a result of the long term goal of product expansion, market expansion and hence, platform sharing and economics (see above). Logistically and economically, it makes sense as a corporate business case. While the N55 is not technically part of the modular platform, it is the engine that kickstarted BMW's portfolio for expansion internationally.
Flexible power, efficient, and falls within 3.0L made it the engine of choice for BMW's expansion.
So yes, we actually won't see a 3.5L I-6, for example, from BMW anytime soon because of current economics. For BMW at this point in time, 3.0L is the magical number, and it is not mere coincidence.