F30POST
F30POST
2012-2015 BMW 3-Series and 4-Series Forum
BMW Garage BMW Meets Register Search Today's Posts Mark Forums Read
BMW 3-Series and 4-Series Forum (F30 / F32) | F30POST > 2012-2019 BMW 3 and 4-Series Forums > General F30 Sedan / F32 Coupe / F36 Gran Coupe Forum > BMW Announces 320i and 320i xDrive for U.S. Market priced at $33,445
GetBMWParts
Post Reply
 
Thread Tools Search this Thread
      01-23-2013, 01:59 PM   #309
bradleyland
TIM YOYO
United_States
21
Rep
1,778
Posts

 
Drives: 2013 M3
Join Date: Jun 2010
Location: Vero Beach, FL

iTrader: (0)

Garage List
Quote:
Originally Posted by f11tw View Post
+1

In November last year, a technical training session on N20 engine was offered to selective customers by a BMW dealer in Beijing, China. During the session the BMW trainer basically confirmed that the top shape of the piston head is different in 20i and 28i models. This is consistent with what one would logically derive from the compression ratio formula - reduced clearance volume resulting in higher compression ratio (11: 1 as in the case of 20i).

Unfortunately the post in the hyperlink below is in Chinese. However I think the pics might still be interesting to have a look at. In addition to an N20 engine torn apart, one gets to see many of the key components in this engine, as well as a few close-up shots of the pistons.

http://club.autohome.com.cn/bbs/thre...7972169-1.html
If you view the page in Chrome, you can translate. They talk about the compression ratios after the photo of the chart showing the compression ratios for each model.
__________________
His: 2013 ///M3 - Interlagos Blue Black M-DCT
Hers: 2013 X3 28i - N20 Mineral Silver / Sand Beige / Premium, Tech
Past: 2010 135i - TiAg Coral Red 6MT ///M-Sport
Appreciate 0
      01-23-2013, 04:35 PM   #310
clarence
Lieutenant Colonel
23
Rep
1,544
Posts

 
Drives: F30 328i M-Sport
Join Date: Mar 2006
Location: Hong Kong

iTrader: (0)

Quote:
Originally Posted by bradleyland View Post
Why would they say anything? That's just spinning the absence of information in order to support your argument.

That's *your* theory. I just don't think it holds water. I know enough about manufacturing to know that the kinds of variances you're talking about would make the production of an engine very expensive.
That's the same for all sides of arguments.
If u work in the computer industry u'll know that when yields improve some of those binned can actually be graded higher, that's why some components can be overclocked using stock settings.
Don't u think by making a detuned engine they're utilising nearly all the available production?

Last edited by clarence; 01-23-2013 at 04:56 PM.
Appreciate 0
      01-23-2013, 04:44 PM   #311
clarence
Lieutenant Colonel
23
Rep
1,544
Posts

 
Drives: F30 328i M-Sport
Join Date: Mar 2006
Location: Hong Kong

iTrader: (0)

Quote:
Originally Posted by f11tw View Post
+1

In November last year, a technical training session on N20 engine was offered to selective customers by a BMW dealer in Beijing, China. During the session the BMW trainer basically confirmed that the top shape of the piston head is different in 20i and 28i models. This is consistent with what one would logically derive from the compression ratio formula - reduced clearance volume resulting in higher compression ratio (11: 1 as in the case of 20i).

Unfortunately the post in the hyperlink below is in Chinese. However I think the pics might still be interesting to have a look at. In addition to an N20 engine torn apart, one gets to see many of the key components in this engine, as well as a few close-up shots of the pistons.

http://club.autohome.com.cn/bbs/thre...7972169-1.html
The N20 20i fitted to E84 & F25 have same compression as N20 28i, so do others for certain markets.
The Q&A said in theory if u change the pistons & ECU u'll get a 28i, but they do not support that idea.
Appreciate 0
      01-23-2013, 11:18 PM   #312
f11tw
New Member
0
Rep
10
Posts

 
Drives: BMW F11
Join Date: Jan 2013
Location: Taiwan

iTrader: (0)

Quote:
Originally Posted by clarence View Post
The N20 20i fitted to E84 & F25 have same compression as N20 28i, so do others for certain markets.
The Q&A said in theory if u change the pistons & ECU u'll get a 28i, but they do not support that idea.
Let's separate the discussion into two parts:

Regarding the 11:1 compression ratio (high CR) 20i engine on RWD 320i and 520i: although there is no direct evidence against the "binning" theory, at least now there is solid proof that the variance in quality is not "the only" difference between the high CR 20i engine and the 28i engine. BMW needs some limiting factors on the 20i engine so that they can preserve the differentiation between 20i and 28i engines, especially in their bread and butter segments - 3ers and 5ers. IMHO, they cleverly use the different shape of the piston head to achieve the objective - higher compression ratio subjects the engine to higher probability of knocking when adding boost, and it would be more than a small job to replace the pistons. There could be other forces at work which we may not fully understand yet, e.g. limp mode by DME software.

The previous discussion among you, E90fleet, and others have greatly benefited the community in advancing the understanding about N20 platform before 320i is available in US. I myself appreciate that very much. However I think the discussion about the piston was missing previously.

As to why BMW chooses to use the low-compression version of the N20 20i on X1, X3, Z4, and even x-Drive version of 320i and 520i, it would be another interesting discussion and more understanding of the platform may be discovered in that process. However it does not change the fact about the high CR 20i engine. Check realoem for the part number of the pistons in different engines and you'll know.
Appreciate 0
      01-23-2013, 11:59 PM   #313
clarence
Lieutenant Colonel
23
Rep
1,544
Posts

 
Drives: F30 328i M-Sport
Join Date: Mar 2006
Location: Hong Kong

iTrader: (0)

Quote:
Originally Posted by f11tw View Post
Let's separate the discussion into two parts:

Regarding the 11:1 compression ratio (high CR) 20i engine on RWD 320i and 520i: although there is no direct evidence against the "binning" theory, at least now there is solid proof that the variance in quality is not "the only" difference between the high CR 20i engine and the 28i engine. BMW needs some limiting factors on the 20i engine so that they can preserve the differentiation between 20i and 28i engines, especially in their bread and butter segments - 3ers and 5ers. IMHO, they cleverly use the different shape of the piston head to achieve the objective - higher compression ratio subjects the engine to higher probability of knocking when adding boost, and it would be more than a small job to replace the pistons. There could be other forces at work which we may not fully understand yet, e.g. limp mode by DME software.

The previous discussion among you, E90fleet, and others have greatly benefited the community in advancing the understanding about N20 platform before 320i is available in US. I myself appreciate that very much. However I think the discussion about the piston was missing previously.

As to why BMW chooses to use the low-compression version of the N20 20i on X1, X3, Z4, and even x-Drive version of 320i and 520i, it would be another interesting discussion and more understanding of the platform may be discovered in that process. However it does not change the fact about the high CR 20i engine. Check realoem for the part number of the pistons in different engines and you'll know.
Yes, at that time, which was quite a long time ago last yr, we did discuss abt the difference in compression ratio & some of the differences in part numbers. There were no detailed discussion abt pistons cos no teardown was available then. If I remember correctly, from the ETK at that time, the early batch of U0 was all of the low compression variety.
As to why they made 11:1 version of the 20i (remember it takes R&D resources to increase the CR of the engine due to need to redesign the pistons), I think it has more to do with efficiency gain. Limiting tuning potential is a useful by-product. As the max boost is reduced, they can increase CR w/o risk of detonation.
As for the low CR version, I think we shall leave it as it is for the time being.

http://www.f30post.com/forums/showth...&highlight=N20
http://www.f30post.com/forums/showth...&highlight=N20

Last edited by clarence; 01-24-2013 at 12:08 AM.
Appreciate 0
      01-24-2013, 09:14 AM   #314
grimlock
Lieutenant Colonel
59
Rep
1,811
Posts

 
Drives: F10 N52B30@255PS
Join Date: Sep 2010
Location: Hong Kong

iTrader: (0)

I know nothing about the N20 or the f30 but let me attempt to provide some insights from logic.

1.The n20 in '20s and 28s are mostly identical because BMW wants to reduce costs.
2.It makes sense to differ a few components to make it uneconomical for people to buy '20s and remake them as legit '28s. But not too much (as it costs more), just up to the price difference in the models.
3. Binning engines is stupid; if the differences are so large, the engines would fall apart!!!
4. You can make a '20 as fast as a 28 without changing the hardware differences, by a cheap tune. Although it is not exactly the same, the performance is.
Appreciate 0
      01-24-2013, 09:48 AM   #315
bradleyland
TIM YOYO
United_States
21
Rep
1,778
Posts

 
Drives: 2013 M3
Join Date: Jun 2010
Location: Vero Beach, FL

iTrader: (0)

Garage List
Quote:
Originally Posted by clarence View Post
That's the same for all sides of arguments.
If u work in the computer industry u'll know that when yields improve some of those binned can actually be graded higher, that's why some components can be overclocked using stock settings.
Don't u think by making a detuned engine they're utilising nearly all the available production?
I'm well acquainted with semiconductors (p–n junction anyone?). I'm also well aware of the binning required in the semiconductor industry. However, comparing the two is... well, stupid. There's no other way to say it.

a) Semiconductor manufacturing is much, a much, much younger technology than metal casting and machining.

b) The tolerances for semiconductor performance operate on a nanometer scale, versus engine tolerances. Even for interference fit parts, tolerances are typically 0.0000 inch (ten-thousandths of an inch). There are 2540 nanometers in 0.0001 inches. So, the precision required to manufacture a semiconductor is several orders of magnitude greater than high-precision machine work.

c) Binning and yields are an effect of the technology limits encountered in semiconductor manufacturing. This is not something that engineers intentionally designed in to the process. In other words, it's not desirable. If semiconductor manufacturers could eliminate binning tomorrow, they would. Why would we (humans), having the technology required to manufacture on a nanometer scale, settle for binning in something as well known, and well developed, as metal machine work?

I do not accept the binning assertion on the basis that I don't believe it is necessary. Stated another way, I don't believe that BMW would have significant enough yield issues when manufacturing the N20 to necessitate binning. There is, otherwise, no justification for the binning hypothesis.
__________________
His: 2013 ///M3 - Interlagos Blue Black M-DCT
Hers: 2013 X3 28i - N20 Mineral Silver / Sand Beige / Premium, Tech
Past: 2010 135i - TiAg Coral Red 6MT ///M-Sport
Appreciate 0
      01-24-2013, 10:19 AM   #316
sean10mm
Private First Class
sean10mm's Avatar
United_States
1
Rep
195
Posts

 
Drives: '13 335i xDrive 6MT ZDH
Join Date: Oct 2012
Location: USA

iTrader: (0)

Quote:
Originally Posted by bradleyland View Post
I'm well acquainted with semiconductors (pn junction anyone?). I'm also well aware of the binning required in the semiconductor industry. However, comparing the two is... well, stupid. There's no other way to say it.

a) Semiconductor manufacturing is much, a much, much younger technology than metal casting and machining.

b) The tolerances for semiconductor performance operate on a nanometer scale, versus engine tolerances. Even for interference fit parts, tolerances are typically 0.0000 inch (ten-thousandths of an inch). There are 2540 nanometers in 0.0001 inches. So, the precision required to manufacture a semiconductor is several orders of magnitude greater than high-precision machine work.

c) Binning and yields are an effect of the technology limits encountered in semiconductor manufacturing. This is not something that engineers intentionally designed in to the process. In other words, it's not desirable. If semiconductor manufacturers could eliminate binning tomorrow, they would. Why would we (humans), having the technology required to manufacture on a nanometer scale, settle for binning in something as well known, and well developed, as metal machine work?

I do not accept the binning assertion on the basis that I don't believe it is necessary. Stated another way, I don't believe that BMW would have significant enough yield issues when manufacturing the N20 to necessitate binning. There is, otherwise, no justification for the binning hypothesis.
Semiconductor industry veteran here chiming in to agree with you. The idea that BMW is binning engines based on dyno results is insane. Comparing semiconductor manufacturing and automotive engineering isn't even apples and oranges, it's like comparing apples and elephants.

Put another way, BMW would have to be the most incompetent engine builder in the automotive industry to be seeing enough variation in engine-to-engine horsepower for binning to make sense. Henry Ford probably didn't see a 33% variance in horsepower from one Model T engine to the next, so I'm pretty sure BMW isn't seeing it now building the N20 with fucking robots.
Appreciate 0
      01-24-2013, 11:06 AM   #317
CarFan
Private First Class
United_States
1
Rep
175
Posts

 
Drives: 2013 X5 3.5 Premium
Join Date: Mar 2012
Location: United States

iTrader: (0)

Garage List
Quote:
Originally Posted by grimlock View Post
I know nothing about the N20 or the f30 but let me attempt to provide some insights from logic.

1.The n20 in '20s and 28s are mostly identical because BMW wants to reduce costs.
2.It makes sense to differ a few components to make it uneconomical for people to buy '20s and remake them as legit '28s. But not too much (as it costs more), just up to the price difference in the models.
3. Binning engines is stupid; if the differences are so large, the engines would fall apart!!!
4. You can make a '20 as fast as a 28 without changing the hardware differences, by a cheap tune. Although it is not exactly the same, the performance is.
+1

I am simply unconvinced that the variation levels in output are so substantial that this explain 20 versus 28. Far too expensive a way to determine which engines are supplied and if true it likely means that a significant number of engines go over 300 hp and others can't even get 150. That's a severe design flaw and of the many things known about BMW engines, being under-engineered is not one of their characteristics.
Appreciate 0
      01-24-2013, 11:19 AM   #318
grimlock
Lieutenant Colonel
59
Rep
1,811
Posts

 
Drives: F10 N52B30@255PS
Join Date: Sep 2010
Location: Hong Kong

iTrader: (0)

Quote:
Originally Posted by CarFan View Post
+1

I am simply unconvinced that the variation levels in output are so substantial that this explain 20 versus 28. Far too expensive a way to determine which engines are supplied and if true it likely means that a significant number of engines go over 300 hp and others can't even get 150. That's a severe design flaw and of the many things known about BMW engines, being under-engineered is not one of their characteristics.
Not to mention impossible if the laws of physics are to hold.
You are just burning fuel in a chamber, unless there is something wrong with the air input, friction is the only other thing that can eliminate from performance. If you had any siginificant friction causing this, the part would wear out and break. I mean it's not really possible unless something is malfunctioning.
Appreciate 0
      01-24-2013, 12:35 PM   #319
bradleyland
TIM YOYO
United_States
21
Rep
1,778
Posts

 
Drives: 2013 M3
Join Date: Jun 2010
Location: Vero Beach, FL

iTrader: (0)

Garage List
To be fair, and I can't believe I'm even offering any explanation for this viewpoint, Clarence isn't claiming that the variation accounts for the full difference between the engines. As far as I can tell, he's claiming that some engines, when dyno'd, do not produce the full baseline horsepower expected from the N20 240 HP version. So for example:
  1. Engine rolls off the assembly line and dynos 228 HP (5% lower than expected)
  2. This fails to meet the benchmark, and the engine is then "binned" as a 180 HP version

This is where things get janky. We must assume at this point that the engine will circle back in to some stage of the production where it is re-flashed with the 180 HP ECU package and re-run on the dyno, because we can't simply sell the 180 HP version with "just under" the output of the 240 HP version. That isn't supported by user submitted dyno evidence either.

In order for the scenario described above to make any sense at all, the following conditions must be true:
  • BMW's engine manufacturing has a high defect rate
  • Producing, dyno testing, reflashing, and dyno testing again is less expensive than simply engineering two versions of the engine

I find both of these claims dubious at best.

So it's either all this bullshit, or BMW simply engineered the two engines accordingly and we haven't discovered exactly what component it is that they changed yet.

Which is more probable?
__________________
His: 2013 ///M3 - Interlagos Blue Black M-DCT
Hers: 2013 X3 28i - N20 Mineral Silver / Sand Beige / Premium, Tech
Past: 2010 135i - TiAg Coral Red 6MT ///M-Sport
Appreciate 0
      01-24-2013, 01:42 PM   #320
clarence
Lieutenant Colonel
23
Rep
1,544
Posts

 
Drives: F30 328i M-Sport
Join Date: Mar 2006
Location: Hong Kong

iTrader: (0)

Quote:
Originally Posted by bradleyland View Post
To be fair, and I can't believe I'm even offering any explanation for this viewpoint, Clarence isn't claiming that the variation accounts for the full difference between the engines. As far as I can tell, he's claiming that some engines, when dyno'd, do not produce the full baseline horsepower expected from the N20 240 HP version. So for example:
  1. Engine rolls off the assembly line and dynos 228 HP (5% lower than expected)
  2. This fails to meet the benchmark, and the engine is then "binned" as a 180 HP version

This is where things get janky. We must assume at this point that the engine will circle back in to some stage of the production where it is re-flashed with the 180 HP ECU package and re-run on the dyno, because we can't simply sell the 180 HP version with "just under" the output of the 240 HP version. That isn't supported by user submitted dyno evidence either.

In order for the scenario described above to make any sense at all, the following conditions must be true:
  • BMW's engine manufacturing has a high defect rate
  • Producing, dyno testing, reflashing, and dyno testing again is less expensive than simply engineering two versions of the engine

I find both of these claims dubious at best.

So it's either all this bullshit, or BMW simply engineered the two engines accordingly and we haven't discovered exactly what component it is that they changed yet.

Which is more probable?
Thank you, I've never said the variations can be that big. All I've said is anything less than 245ps can be sold as a U0 after reflashing. Reflashing can be done at the dyno station & after that the engine can be tested again. The engine can stay at the dyno station thruout the process. Also, peak power & torque are not the only criterias, there's also the power & torque curves, amongst other things (e.g. whether the engine produces at least the baseline power & torque thruout the rev range). Strictly speaking they cannot sell the engine as a 28i even if it misses one of these measurements by a hair (e.g. <1%, & I assume that's the biggest variation they're going to get). We have no idea how strict their standards are, & judging by the dyno plots of various O0s in stock form, it can be that by just meeting the baseline is for them considered a failure.

We've already discovered long ago (early last yr to be precise) that there are 2 versions of the U0 engine - one with 11:1 compression & the other with 10:1 compression. The high compression version (fitted to most F30 & F10/11) have unique pistons as described in the Chinese article above. In fact the technical training staff from BMW China confirmed that, for the high compression version, the only physical difference between a U0 & O0 is the pistons. All other mechanical components are identical. Therefore the high compression version is always destined to be a U0 from the very first step in the assembly process.

What's interesting is the low compression version. That engine, fitted to all E84, F25 & some F30s & F10/11s (namely the xDrive version & some specific markets), is identical to O0 part for part. The low compression version did use a different turbo during periods of time in late 2011 (according to ETK), but after that the turbo is the same. For this version of the N20 it's up to u to think how BMW chooses which ones have the priviledge to be a U0 & not a O0.

So far nobody has posted a dyno plot of the U0 in stock form, but the Chinese article did suggest that, like the O0, the factory claims are conservative.
Appreciate 0
      01-24-2013, 02:23 PM   #321
bradleyland
TIM YOYO
United_States
21
Rep
1,778
Posts

 
Drives: 2013 M3
Join Date: Jun 2010
Location: Vero Beach, FL

iTrader: (0)

Garage List
So what happens when they're short on defect engines? Do they simply down-bin competent engines? They'd have to, because current automobile manufacturing strategies don't include stocking warehouses full of engines for no good reason. That means we should see '20i engines on the market that are fully capable of '28i output.

BMW isn't renowned for their super-short supply chains, but they're not sloppy either. The problem with binning is that it relies on a statistical distribution of yields in large runs. Microprocessors are manufactured in much larger lots than engines, so it works for them. Processors are also sold a lot like commodities. Fluctuations in pricing at at the low-end can occur independently of price changes at the high end. There are price constraints, but the defect rate in microprocessors follows a curve that is often similar to the pricing curve (until much later in production). This is not coincidence. All of this is an emergent (bottom-up) system based on the fact that microprocessor manufacturing pushes the boundaries of our best technology.

This model makes no sense with automobiles where customers dictate orders. BMW can't simply release engines to market in whatever quantities they want. They have orders to fill. BMW doesn't release a batch of cars on to the market; BMW dealers order their cars just like a customer can.

Imagine the difficulty in aligning the defect rate of engine design and manufacture to anticipated customer demand. If the defect rate turns out too high, BMW has to eat that loss. The price window for their car line up is too tight for them to treat their engines as commodities subject to internal supply side fluctuations. This is something they would *have* to control tightly or they'd be giving up a significant competitive advantage to every other manufacturer.

The short version is that, not only does it not make sense from an engineering perspective, it doesn't make sense from a supply chain and economic perspective either. Not buying it.
__________________
His: 2013 ///M3 - Interlagos Blue Black M-DCT
Hers: 2013 X3 28i - N20 Mineral Silver / Sand Beige / Premium, Tech
Past: 2010 135i - TiAg Coral Red 6MT ///M-Sport
Appreciate 0
      01-24-2013, 02:33 PM   #322
grimlock
Lieutenant Colonel
59
Rep
1,811
Posts

 
Drives: F10 N52B30@255PS
Join Date: Sep 2010
Location: Hong Kong

iTrader: (0)

It makes it far more complicated than it is worth it, especially given the ground assumption that inherent differences are very, very small, say in the 1% range.

It's more logical for BMW to fit different turbos and cooling (as mentioned b4) so that increasing the output of the 20i without changing these components is not recommended.
Probably less than 1/20 20i's sold will be chipped so BMW would just let these guys have the free lunch that only costs them what 4-5k USD and they don't have to mess around with different components to spite the knowledgeable DIYer.
Appreciate 0
      01-24-2013, 04:00 PM   #323
clarence
Lieutenant Colonel
23
Rep
1,544
Posts

 
Drives: F30 328i M-Sport
Join Date: Mar 2006
Location: Hong Kong

iTrader: (0)

Quote:
Originally Posted by bradleyland View Post
So what happens when they're short on defect engines? Do they simply down-bin competent engines? They'd have to, because current automobile manufacturing strategies don't include stocking warehouses full of engines for no good reason. That means we should see '20i engines on the market that are fully capable of '28i output.
So u're now saying BMW doesn't have a consistent & predictable defect rate. I would say they already have enough statistics on the N20 as it's already in production for over 2 yrs. They know roughly how many units per mth that are considered as defective, everything else being equal. So wht do u think they'll do to those defective units, junk them? If they run out of defective units then they'll have to use good units, but it's only for the low compression version cos the high compression version is built as a U0 right from the start. It bears no extra cost to them as the BOM is the same for the whole N20 family (see the article).

There will be no impact to the supply chain etc. etc. cos, the defect rates are very likely to be lower than demand for the low compression version. It will only become a problem if the defect rates are higher than the demand as u said (unlikely in this case). Also the lead time for the engines are abt 1-1.5 mth (only 2 plants in Europe supplies the world), so they have enough time to plan production allocation.

Do customers really dictate orders? Sometimes they do but sometimes that's not the case. Frequently in the past they had to subsidise certain versions or models in order to fill the production capacity (e.g. F07 in Europe & Asia). They also sometimes do release a batch of cars to the market, with certain incentives to certain importers.

Last edited by clarence; 01-24-2013 at 04:14 PM.
Appreciate 0
      01-24-2013, 04:10 PM   #324
clarence
Lieutenant Colonel
23
Rep
1,544
Posts

 
Drives: F30 328i M-Sport
Join Date: Mar 2006
Location: Hong Kong

iTrader: (0)

Quote:
Originally Posted by grimlock View Post
It makes it far more complicated than it is worth it, especially given the ground assumption that inherent differences are very, very small, say in the 1% range.

It's more logical for BMW to fit different turbos and cooling (as mentioned b4) so that increasing the output of the 20i without changing these components is not recommended.
Probably less than 1/20 20i's sold will be chipped so BMW would just let these guys have the free lunch that only costs them what 4-5k USD and they don't have to mess around with different components to spite the knowledgeable DIYer.
As mentioned before, the high compression version have different pistons but the low compression version is identical (again confirmed by ETK & BMW China technical rep). So how do they choose between identical engines to be a 20i & a 28i (talking abt low compression version only)? Randomly? Or is it better to use defective ones or underperforming ones (for a 28i) & detune it to be in-spec for a 20i? How complicated can that be when the defective rates are low?
Appreciate 0
      01-24-2013, 04:16 PM   #325
bradleyland
TIM YOYO
United_States
21
Rep
1,778
Posts

 
Drives: 2013 M3
Join Date: Jun 2010
Location: Vero Beach, FL

iTrader: (0)

Garage List
Quote:
Originally Posted by clarence View Post
So u're now saying BMW doesn't have a consistent & predictable defect rate.
No, that's not what what I'm saying at all. I never said anything like that. If anything, I'd say that they're able to build engines in a way that identifies defects before the engine reaches the dyno, and that each engine is built from beginning to end as it's final outcome intends. It's very easy, and cost effective, to recycle out-of-spec components like a block or head casting. Verification of dimensional accuracy is 100% automated, so it's a cheap way to dramatically reduce the very kind of variances you're claiming results in this binning approach.

Quote:
Originally Posted by clarence View Post
I would say they already have enough statistics on the N20 as it's already in production for over 2 yrs. They know roughly how many units per mth that are considered as defective, everything else being equal. So wht do u think they'll do to those defective units, junk them? If they run out of defective units then they'll have to use good units, but it's only for the low compression version cos the high compression version is built as a U0 right from the start. It bears no extra cost to them as the BOM is the same for the whole N20 family (see the article).
You should really step back and listen to what you're saying. Essentially, it's one way for one engine, and an entirely other way for another. They're able to build U0 engines entirely to spec, but the O0 engines are binned according to their output. Does that make any sense at all?


Quote:
Originally Posted by clarence View Post
As mentioned before, the high compression version have different pistons but the low compression version is identical (again confirmed by ETK & BMW China technical rep). So how do they choose between identical engines to be a 20i & a 28i (talking abt low compression version only)? Randomly? Or is it better to use defective ones or underperforming ones (for a 28i) & detune it to be in-spec for a 20i? How complicated can that be when the defective rates are low?
So you (or someone) has verified every single part number and every aspect of the software running on these two engines? There is a gulf of difference between "they are identical" and "we have not identified a difference".
__________________
His: 2013 ///M3 - Interlagos Blue Black M-DCT
Hers: 2013 X3 28i - N20 Mineral Silver / Sand Beige / Premium, Tech
Past: 2010 135i - TiAg Coral Red 6MT ///M-Sport
Appreciate 0
      01-24-2013, 04:41 PM   #326
clarence
Lieutenant Colonel
23
Rep
1,544
Posts

 
Drives: F30 328i M-Sport
Join Date: Mar 2006
Location: Hong Kong

iTrader: (0)

Quote:
Originally Posted by bradleyland View Post
You should really step back and listen to what you're saying. Essentially, it's one way for one engine, and an entirely other way for another. They're able to build U0 engines entirely to spec, but the O0 engines are binned according to their output. Does that make any sense at all?
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.



Quote:
Originally Posted by bradleyland View Post
So you (or someone) has verified every single part number and every aspect of the software running on these two engines? There is a gulf of difference between "they are identical" and "we have not identified a difference".
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.
Appreciate 0
      01-24-2013, 04:57 PM   #327
Propagator
Captain
9
Rep
808
Posts

 
Drives: 2011 328i LMB 6MT
Join Date: Dec 2006
Location: CA

iTrader: (0)

Clarence, the biggest problem with your binning argument is that it doesn't explain at all why tuners are not able to get the same level of power out of x20i as the x28i ON THE DYNO.

I am sure some level of binning exist in any manufacturing. But, let's think about this hypothetical binning of yours. The ones that pass the test are the ones that can generate ~240HP for a reasonable amount of mileage, say 100K, without blowing up. And the ones that fail are the ones that can't generate the same power at the same boost, so they would detune it and sell it as x20i.

BUT, this does not mean that the failed ones would blow up as soon as you up the boost to 328i level, even if your conjecture was true. It could mean that when the boost gets turned up, the longevity of the engine will fall below the acceptable level. But that alone will most definitely not stop a tuner from bumping up the power and selling the reflash. No aftermarket company is going to do a 100k mile test to see if the tune holds up.

Now, it could be that BMW has put extra guard against high boost in the software to prevent people from pushing these "defective" engines too far. But if that is the case, then the direct reason for the tuners' supposed inability to get the power is NOT the quality of the engine, but the software. It could be that once they crack the software, the owners with the tune may find that their engines break down after 50k miles. But that hasn't happened, apparently because people can't make big power out of it. This very strongly suggests that binning cannot be the only, and even the most relevant, explanation for this problem.
Appreciate 0
      01-24-2013, 05:31 PM   #328
bradleyland
TIM YOYO
United_States
21
Rep
1,778
Posts

 
Drives: 2013 M3
Join Date: Jun 2010
Location: Vero Beach, FL

iTrader: (0)

Garage List
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.
__________________
His: 2013 ///M3 - Interlagos Blue Black M-DCT
Hers: 2013 X3 28i - N20 Mineral Silver / Sand Beige / Premium, Tech
Past: 2010 135i - TiAg Coral Red 6MT ///M-Sport
Appreciate 0
      01-24-2013, 06:58 PM   #329
Jamesons Viggen
Brigadier General
United_States
50
Rep
3,573
Posts

 
Drives: '98 M Roadster stg 2+ S/C
Join Date: Jul 2012
Location: Rochester Hills MI

iTrader: (3)

I am a Saab guy. I am used to this. There was the 2.0t and 2.0T, nearly identical engines with differing outputs. Same with the b235r and b235e which had different valves and or pistons besides the ecu tune.
__________________
'98 M Roadster S/C @11-16ps
'06 Saab 9-5 wagon 5mt Aero+ Tuned
Appreciate 0
      01-24-2013, 10:59 PM   #330
clarence
Lieutenant Colonel
23
Rep
1,544
Posts

 
Drives: F30 328i M-Sport
Join Date: Mar 2006
Location: Hong Kong

iTrader: (0)

Quote:
Originally Posted by bradleyland View Post
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.
Tho I have not researched into minute details over other BMW engines, they have been offering this "single type of engine in various states of tunes" for many years. The binning approach, I suspect, is only good for turbocharged engines as they're more stressed than NA engines (hence the need for more precise tolerances & construction methods).
BMW offers turbo diesel engines that are of a single family but in various different outputs for many years, so if indeed that's whts going on then they're not new to the game (& neither is for other European makes).


Quote:
Originally Posted by bradleyland View Post
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.
There are bound to be variations in outputs, however small, so it's just a way of cost savings.
Appreciate 0
Post Reply

Bookmarks

Tags
3 series f30, 3 series f30 forum, 3 series forum, bmw 3 series forum, bmw 3-series f30, bmw 320i, bmw 320i forum, bmw f30, bmw f30 3-series, bmw f30 forum, f30 3-series, f30 3-series forum, f30 forum, f30 forums

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump


All times are GMT -5. The time now is 10:00 AM.




f30post
Powered by vBulletin® Version 3.7.0
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
1Addicts.com, BIMMERPOST.com, E90Post.com, F30Post.com, M3Post.com, ZPost.com, 5Post.com, 6Post.com, 7Post.com, XBimmers.com logo and trademark are properties of BIMMERPOST