10-14-2018, 03:49 AM | #45 | |
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Do you guys realize how dumb it would be to design something and provide strong suggestions in the owners manual that nobody reads to ensure the longevity of the vehicle? If any engineer was so concerned with break in being a big deal you know what would happen? The car would basically be set to limp mode for the first 1500 miles. But I digress...it's more fun to just read these comments and laugh inside |
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10-14-2018, 04:31 AM | #46 | |
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10-14-2018, 06:57 AM | #47 |
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Well one thing internet forums do quickly show you is who you would and would not hire as engineers for your company.
For an "engineer" to believe something like a mass produced differential bevel gear experiences no mating surface break-in during the early life cycle process simply shows that said engineer perhaps needs remedial training. Similarly, to believe that a clutch disc doesn't require a break-in period to mate fully with the flywheel and pressure plate in order to achieve it's maximum rated clamping force is asinine. In fact, a clutch can easily be ruined by ignoring this needed process; ruined from the standpoint of never being able to achieve rating clamping force. Yet you see this BS all the time on the web with "engineers" claiming there is no such break-in process. ME is a "science" and all of the above are provable and known facts. Beliefs on the other hand are just that. I guess in the modern world were facts don't matter, it's pointless to have such a discussion on a random internet site.
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10-14-2018, 11:27 AM | #48 | |
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To make money? Is there money in building cars that last 10 years now No! You engineer and design a car to run flawlessly during its warranty period and for it to fall apart after, that’s how you maximize profits... Last edited by slowestM2; 10-14-2018 at 12:16 PM.. Reason: MISTAKES WERE MADE |
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10-14-2018, 11:32 AM | #49 | |
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I see the logic in not building to last past warranty, but the actual logic would be to last at least as long as competitor's regardless of warranty. Gotta maintain a reputation. |
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10-14-2018, 11:36 AM | #50 |
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BMW pays out a humongous sum of money on M-cars draining and replacing differential lube during the 1200 mile service. This is directly a result of bevel gear break-in and LSD clutch pack break-in particles from the initial mating period they want out of there. I think anyone can say with authority that if BMW engineering didn't win this battle with the Finance group, there's no way they'd be paying for this service (times 10s of thousands of cars per year).
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10-14-2018, 12:16 PM | #51 | |
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The only people they are concerned with are the people buying/leasing brand new cars. The cars depreciate to half value over 5 years... no money to be made with the peasants. Selling and leasing 40-100k dollar cars to people that can afford new ones every 3-6 years is where there bread and butter is. Good to know the diff fluid is changed, that is one of the few pieces that in break in if it sees a lot of abuse can create quite a bit of metal, but thats what the metallic drain plug is for |
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10-14-2018, 05:45 PM | #53 | |
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[QUOTE=akkando;23850188]
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Okay, good! I feel better about having meticulously, anally followed all the guidelines! 1) My diff and transmission will thank me, and 2) I didn't accidentally kill myself - always a plus! |
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10-14-2018, 06:19 PM | #54 | |
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I am not saying it is a bad idea to change the fluid, we all agree it may have a longer life if it's done. If not doing it was so deleterious though, why does Porsche not even have a 1200 or 2000 mile fluid change for 911s with the same electronically actuated clutch-pack type differential? I am pretty sure Porsche could get away with the adding cost of a fluid change to a 911 GT3, given that people are paying huge amounts over sticker for them. You are also guilty of armchair engineering here if you don't have access to the design documentation from the supplier of the differential (GKN made the old one, not sure about the new one). My point is, none of us know all the reasons they do the 1200 mile service still. I am sure it was a battle that engineering won years ago, maybe it's something that hasn't been revisited. German corporate culture can be very rigid. |
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10-14-2018, 06:22 PM | #55 | |
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Maybe they put a stop to it after techs kept destroying DCTs by filling them with MT fluid when the E92 came out. |
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10-14-2018, 06:31 PM | #56 |
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It's not "armchair engineering" when there are exactly two potential sources for break-in wear material to be deposited into differential lube, and one simply states those as the reason BMW chooses to spend many millions of dollars per year to remove that lube at the 1200 mile service. Unless you have the belief that they are doing this diff lube change as some marketing ploy. LSD clutch discs absolutely bed into their spring plates similar to a transmission clutch disc. Stating a fact is not armchair engineering. Speculating on why some manufacturers choose not to change diff lube early would immediately enter armchair guessing as to the reasons.
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10-14-2018, 06:39 PM | #57 | |
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You might be right, but you're still making an educated guess, just like everyone else. |
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10-14-2018, 06:43 PM | #58 | |
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Also lmao at remedial training. You do realize that mechanical engineering is a broad study and hardly anyone specializes in automotive? Hell its a 4 year degree where the first two years are filled with physics math and other hoopla from GE. As someone that has done FSAE in school and participated as an evaluator, your statements would get eaten alive at comp. But that's neither here nor there...I stand by statemrnt, break in is mostly "err on the side of caution" than a science or hard rule |
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10-14-2018, 06:55 PM | #59 | |
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10-14-2018, 07:20 PM | #60 |
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10-14-2018, 07:27 PM | #61 |
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Yes it was a DCT. The main question would be how much particulates are in there. The engine is definitely going to have some during break in. I've gotten an N54 lab tested to prove it. But how much is too much. Is the factory diff fluid special? And if the average owner doesn't care due to turning over the car quickly, then no big deal.
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10-15-2018, 07:05 AM | #62 | |
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Similarly, BMW has published their empirically derived clutch disc to pressure plate and flywheel break-in instructions long ago. They zeroed in on 800-1000 shifts done under low to moderate load conditions during a period where no excessive slippage or major power transfer is allowed. I've simply restated that many times, but apparently BMW's own engineering team's empirical data is worthless to a few here who would rather ridicule and spread false impressions. BMW published break-in instructions for the clutch in the M2C owner's manual; however, they've translated it into "300 miles" which may or may not achieve what they target. It's the best you can do when marketing won't allow you to put what you want there. They're assuming that 300 miles achieves enough shifting done moderately in the majority of cases.
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10-15-2018, 07:17 AM | #63 | |
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10-15-2018, 07:20 AM | #64 | ||
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A difference of 70whp (M2C over OG M2) would yield far more than 1s -1.5s improvement 100-200kph ie m2 low to mid 11s vs M2C low 10s
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10-16-2018, 03:36 AM | #65 | |
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Since empirical data exists, I'm excited to review it ! |
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10-16-2018, 04:19 AM | #66 | |
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Bet you $100 that the Z4 M40i with the same exact differential that's in the M2 doesn't get a 1200 mile fluid change. |
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