[aerokubectl]

Originally Posted by dirtydesmo

All those things you are listing aren’t adversely impacted
from mph, only rpm and load... again.

For real break in you want varying rpm and load, you want to slowly and progressively increase heat, rpm, and load during I initial break-in.

I guarantee you these cars are all fully broken in, driven and revved from 2k to redline at all load levels before they are shipped out

Mechanical engineering is actually a science and the bulk of what’s in your owners manual is marketing science....

I actually have a mechanical engineering degree and it's embarrassing to see all the BS spread here lmao. None of you have any clue on the materials used in the gearing, what the impact specific lubricants have and how it all works under temp and load. Randomly saying shit like mechanical engineering is a science proves nothing and it does a diservice to actual engineers.

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

[MrOhnoez]

Originally Posted by oshalygin

I actually have a mechanical engineering degree and it's embarrassing to see all the BS spread here lmao. None of you have any clue on the materials used in the gearing, what the impact specific lubricants have and how it all works under temp and load. Randomly saying shit like mechanical engineering is a science proves nothing and it does a diservice to actual engineers.

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

That wouldn't work so well with test drives. I'm sure there is also some sort of liability there. Claiming a car can do "X" at time of sale but NOT before 1200 miles I'm sure someone would sue for something...

[CSBM5]

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.

[slowestM2]

Originally Posted by oshalygin

I actually have a mechanical engineering degree and it's embarrassing to see all the BS spread here lmao. None of you have any clue on the materials used in the gearing, what the impact specific lubricants have and how it all works under temp and load. Randomly saying shit like mechanical engineering is a science proves nothing and it does a diservice to actual engineers.

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

Why does any auto manufacturer exist?

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...

[zenmaster]

Originally Posted by dirtydesmo

If anything you said was actually true the differential
And trans fluid would be drained after break-in mileage, but they aren’t...

My break in work order says differential fluid (and engine oil) was changed. Transmission fluid was not.

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.

[CSBM5]

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).

[slowestM2]

Originally Posted by zenmaster

My break in work order says differential fluid (and engine oil) was changed. Transmission fluid was not.

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.

BMW isn't building cars for 2nd owners and people buying out of warranty.

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

[akkando]

[QUOTE=Poochie;23847020]

Some say the break in is more for the differential and transmission.

[cptobvious]

[QUOTE=akkando;23850188]

Originally Posted by Poochie

Some say the break in is more for the differential and transmission.

Ah... that makes sense too.

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!

[chris719]

Originally Posted by CSBM5

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).

What if the new Z4 with the same differential doesn't get a 1200 mile service?

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.

[chris719]

Originally Posted by zenmaster

My break in work order says differential fluid (and engine oil) was changed. Transmission fluid was not.

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.

Was your car a DCT? My Z4M had the MT transmission fluid replaced at the break-in service. I guess they feel the DCT is a lifetime fluid.

Maybe they put a stop to it after techs kept destroying DCTs by filling them with MT fluid when the E92 came out.

[CSBM5]

Originally Posted by chris719

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).

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.

[chris719]

Originally Posted by CSBM5

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.

Since you know all about the design, I guess you know exactly what materials are in this diff and if it's been pre-bedded in or not before delivery to BMW for installation, and you have the FMEA / reliability analysis data on it. I am also sure you were in the meetings at BMW where they decided it was still crucial and necessary to do it.

You might be right, but you're still making an educated guess, just like everyone else.

[aerokubectl]

Originally Posted by CSBM5

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.

Lmao, ok man. I never disagreed with your assessment that there's a break in period for various components. What I disagree with is the fact that you can sit there and say that without a specific protocol for a break in, the car will never achieve the rated performance or that it would negatively impact long term reliability.

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

[chris719]

Originally Posted by oshalygin

Lmao, ok man. I never disagreed with your assessment that there's a break in period for various components. What I disagree with is the fact that you can sit there and say that without a specific protocol for a break in, the car will never achieve the rated performance or that it would negatively impact long term reliability.

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

Exactly, since he does not have access to any of the data that you would need to come to a sound conclusion, his hypothesis is just as much conjecture as anyone else's in this thread.

[zenmaster]

Originally Posted by dirtydesmo

BMW isn't building cars for 2nd owners and people buying out of warranty.

The third option is 1st owners that simply drive their cars more.

[zenmaster]

Originally Posted by chris719

Was your car a DCT? My Z4M had the MT transmission fluid replaced at the break-in service. I guess they feel the DCT is a lifetime fluid.

Maybe they put a stop to it after techs kept destroying DCTs by filling them with MT fluid when the E92 came out.

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.

[CSBM5]

Originally Posted by chris719

Since you know all about the design, I guess you know exactly what materials are in this diff and if it's been pre-bedded in or not before delivery to BMW for installation, and you have the FMEA / reliability analysis data on it. I am also sure you were in the meetings at BMW where they decided it was still crucial and necessary to do it.

You might be right, but you're still making an educated guess, just like everyone else.

It's a very simple rule that I've used for many decades -- follow the money. If BMW is willing to spend millions of dollars per year changing differential lube at 1200 miles on M-cars, and owners of said cars mostly have zero clue about it (i.e. it's not a marketing exploitable scheme), there is clearly in *their opinion, not mine* a reason behind their plan. I'm simply stating the obvious -- said reason is break-in material removal from differential lube. The source of said contamination is either from the bevel gears, the LSD discs, or both. Unless you know of another reason that you're keeping hidden?

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.

[CSBM5]

Originally Posted by oshalygin

Lmao, ok man. I never disagreed with your assessment that there's a break in period for various components. What I disagree with is the fact that you can sit there and say that without a specific protocol for a break in, the car will never achieve the rated performance or that it would negatively impact long term reliability.

Now you're assigning your belief about what I've stated and trying to apply it inappropriately. A clutch disc that isn't properly bedded in will likely not achieve its rated clamping load. This is from BMW's empirical data which they published many years ago during the S62 era. It's not my data; I'm simply restating what we all know is the case about clutch discs and fresh flywheels/pressure plates for which BMW has published their actual empirical information -- it's BMW's data and their recommendation that I've restated here. If their published data doesn't fit your opinion, that's fine, who cares.

[Bee Pee]

Originally Posted by ryem3

Wow, so we're looking at 330 to 400 whp. No wonder this thing feels a lot faster. Seems to pull harder at all points of the rev band. And I definitely feel limited keeping the thing under 5500 rpm.

I smell a rat re m2c stock output.

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

[aerokubectl]

Originally Posted by CSBM5

Now you're assigning your belief about what I've stated and trying to apply it inappropriately. A clutch disc that isn't properly bedded in will likely not achieve its rated clamping load. This is from BMW's empirical data which they published many years ago during the S62 era. It's not my data; I'm simply restating what we all know is the case about clutch discs and fresh flywheels/pressure plates for which BMW has published their actual empirical information -- it's BMW's data and their recommendation that I've restated here. If their published data doesn't fit your opinion, that's fine, who cares.

Care to share a link to said study and reference to the exact materials/loads seen in an M2c? It's not that I don't believe you, I just want to see this study where they predicted the future in their study.

Since empirical data exists, I'm excited to review it !

[chris719]

Originally Posted by CSBM5

Now you're assigning your belief about what I've stated and trying to apply it inappropriately. A clutch disc that isn't properly bedded in will likely not achieve its rated clamping load. This is from BMW's empirical data which they published many years ago during the S62 era. It's not my data; I'm simply restating what we all know is the case about clutch discs and fresh flywheels/pressure plates for which BMW has published their actual empirical information -- it's BMW's data and their recommendation that I've restated here. If their published data doesn't fit your opinion, that's fine, who cares.

S62 is a 23 year old design at this point. I don't doubt that the general wisdom is the same, but unless you have access to the actual, current data you don't know anything more than anyone else on the outside.

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.