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      01-24-2013, 05:31 PM   #328
bradleyland
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Quote:
Originally Posted by clarence View Post
Firstly u must distinguish between the high compression & low compression U0 engine. The high compression U0 engine cannot run at 28i's level of boost cos of detonation (even tho the turbo is identical) whereas the low compression ratio U0 can (as it's identical to O0). This is confirmed in the article by BMW China's technical rep (they build both U0 & O0 at Shenyang China). So the U0 is already less stressed than the O0. In any case the high compression one doesn't need binning at all cos all defective ones are junk as there's no lower state of tune than U0 for a N20. The low compression ones are tuned to U0 or O0 from binning. U0 & O0 is only the engine code for it's state of tune, other than that it doesn't identify anything else. So, U0=20i & O0=28i.
That's central to my point. For what other engines does BMW use this binning approach? Is this something new? I've never heard of it applied to complex assemblies like an entire engine. The output is strictly a sum of all the parts, and those parts are scrutinized throughout the process for the very purpose of eliminating final stage anomalies.

Quote:
Originally Posted by clarence View Post
We (a number of us) identified key parts for the low compression version & they have the same part number. The software is of course not the same (but the DME part number is identical). The "identical part" came, again, from the BMW China tech rep from the article. He explicitly said, when questioned, that the high compression U0 & low compression O0 is identical in every part except for the pistons.
That's good information, and it's closer to the source than anything I've seen thus far, but my spidey sense is still all lit up over the binning approach for something as complex as an engine.
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Past: 2010 135i - TiAg Coral Red 6MT ///M-Sport