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      12-31-2019, 10:05 AM   #1
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Tuned N55 crank hub issues

Curious if anyone has ever heard of a N55 crank hub spinning? Now that I am back in my og M2 I am contemplating doing some preventive maintenance, but I can't find anyone who has ever had an issue. Has anyone else heard anything?
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      12-31-2019, 10:18 AM   #2
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Even though the N55 runs the same crank hub design as the S55, the N55 doesn't produce enough power to cause a spun crank hub. Good piece of mind to have lol.
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      12-31-2019, 03:11 PM   #3
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Quote:
Originally Posted by hlm2c View Post
Even though the N55 runs the same crank hub design as the S55, the N55 doesn't produce enough power to cause a spun crank hub. Good piece of mind to have lol.
Not entirely the when story...

Power might not be the only relevant factor, if the hub spins it can spin at any power level and any rpm in the s55. The n54 shares the same hub and most tuned N54's and even high power turbo upgrade ones don't see the spinning hub issue. The only case I have heard was the VTT car, but they announced that as soon as they made their CBC so take that as you will... They could be a very rare case because they do make an exceptionally high amount of power.


I think the s55 spins easier due to a few features: the timing system drives two hpfps instead of one, the timing system also drives a larger oil pump, timing system also drives a water pump which is not electric on the s55, and the dct down shifts alot harder than non dct equipped N54's and n55's. This makes some sense since the s55's have been reported to spin even while cruising.


I've also seen higher horse power s55's soon easier than non s55 cars, though there has been a lot of debate as to why.
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      01-07-2020, 08:55 PM   #4
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Quote:
Originally Posted by F87source View Post
Quote:
Originally Posted by hlm2c View Post
Even though the N55 runs the same crank hub design as the S55, the N55 doesn't produce enough power to cause a spun crank hub. Good piece of mind to have lol.
Not entirely the when story...

Power might not be the only relevant factor, if the hub spins it can spin at any power level and any rpm in the s55. The n54 shares the same hub and most tuned N54's and even high power turbo upgrade ones don't see the spinning hub issue. The only case I have heard was the VTT car, but they announced that as soon as they made their CBC so take that as you will... They could be a very rare case because they do make an exceptionally high amount of power.


I think the s55 spins easier due to a few features: the timing system drives two hpfps instead of one, the timing system also drives a larger oil pump, timing system also drives a water pump which is not electric on the s55, and the dct down shifts alot harder than non dct equipped N54's and n55's. This makes some sense since the s55's have been reported to spin even while cruising.


I've also seen higher horse power s55's soon easier than non s55 cars, though there has been a lot of debate as to why.
Quote:
Originally Posted by F87source View Post
Quote:
Originally Posted by hlm2c View Post
Even though the N55 runs the same crank hub design as the S55, the N55 doesn't produce enough power to cause a spun crank hub. Good piece of mind to have lol.
Not entirely the when story...

Power might not be the only relevant factor, if the hub spins it can spin at any power level and any rpm in the s55. The n54 shares the same hub and most tuned N54's and even high power turbo upgrade ones don't see the spinning hub issue. The only case I have heard was the VTT car, but they announced that as soon as they made their CBC so take that as you will... They could be a very rare case because they do make an exceptionally high amount of power.


I think the s55 spins easier due to a few features: the timing system drives two hpfps instead of one, the timing system also drives a larger oil pump, timing system also drives a water pump which is not electric on the s55, and the dct down shifts alot harder than non dct equipped N54's and n55's. This makes some sense since the s55's have been reported to spin even while cruising.


I've also seen higher horse power s55's soon easier than non s55 cars, though there has been a lot of debate as to why.


This makes sense. I have yet to find one single person who has ever spun the crank hub on an N55 even when running PS2. I have seen a couple of cases where this happened on N54 but the power levels were just insane and still it seems to be extremely rare. Do you think the this could also be due to being a true twin turbo vs just a twin scroll?
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      01-07-2020, 09:54 PM   #5
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Quote:
Originally Posted by Msm1984 View Post
This makes sense. I have yet to find one single person who has ever spun the crank hub on an N55 even when running PS2. I have seen a couple of cases where this happened on N54 but the power levels were just insane and still it seems to be extremely rare. Do you think the this could also be due to being a true twin turbo vs just a twin scroll?
Turbo setup shouldn't have any effect, it could be possible if it was supercharged as it would be belt driven off the crank but since that's not the case as twin charged cars are so rare even outside of the bmw world that discussion should be irrelevant.

Anyways no imo being a twin turbo car vs. single turbo shouldn't have much of an effect if any.

Edit- twins could allows for faster spooling and more power down low when upgrading to larger turbos, but any effect would be minimal and shouldn't contribute to spinning the hub imo.
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      01-09-2020, 12:38 PM   #6
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I did see a TSB for the N55 bedplate. I didn't look into it much, so I don't know what model years it's for. But I remember someone said it's related to the crank hub.

EDIT: here is what I'm talking about.

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      01-10-2020, 04:19 AM   #7
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Quote:
Originally Posted by Anthony1s View Post
I did see a TSB for the N55 bedplate. I didn't look into it much, so I don't know what model years it's for. But I remember someone said it's related to the crank hub.

EDIT: here is what I'm talking about.

Interesting, ive heard of the new bed plate design for the S55 awhile back but I don't recall the year.

Btw where do you get TSB info from?
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      01-10-2020, 10:54 AM   #8
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Quote:
Originally Posted by F87source View Post
Interesting, ive heard of the new bed plate design for the S55 awhile back but I don't recall the year.

Btw where do you get TSB info from?
I installed remote access onto my dealer's computer while he was in the bathroom...

jk, I get theom from here. http://www.carproblemzoo.com/tsb/bmw/m2/
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      01-10-2020, 05:46 PM   #9
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Quote:
Originally Posted by F87source View Post
Interesting, ive heard of the new bed plate design for the S55 awhile back but I don't recall the year.

Btw where do you get TSB info from?
I was speaking with my service advisor today and he said that TSB only says to use loctite on the bedplate bolts. I used to be able to read the TSB repair procedures myself, so not sure if that website changed or if I was reading them on a different website. But there isn't a redesigned bedplate for us like the S55 had. Also was asking if I could get that TSB done as preventative maintenance and if TSB's were covered outside of warranty. Here's what he said.

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      01-10-2020, 06:18 PM   #10
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Quote:
Originally Posted by Anthony1s View Post
I was speaking with my service advisor today and he said that TSB only says to use loctite on the bedplate bolts. I used to be able to read the TSB repair procedures myself, so not sure if that website changed or if I was reading them on a different website. But there isn't a redesigned bedplate for us like the S55 had. Also was asking if I could get that TSB done as preventative maintenance and if TSB's were covered outside of warranty. Here's what he said.

Interesting, thanks for the info.

I wonder how much work it would take to diy it.
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