Spun Crank Hub 6MT

SLOWESTN54

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My close friends N54 Unfortunately spun a Crank hub yesterday, The cherry on top was that i was driving....

The car is Rwd and manual, has FBO+inlets running 17psi through daw stage 2's, on a E50 tune with 8*'s of timing in it. This was the 5th pull maybe on this map. Before this he was on a safe 14psi pump gas tune. Car has 160k miles on it, no prior work related to the crank hub. Also it has a factory dual mass flywheel.

The events prior to it happening, I was doing a flyby for him so he could record. I slightly brake boosted 2nd, and as i clutched in to go to third the engine died with a unpleasant noise.

Diagnoses so far is that the crank bolt backed out.
 

SlowE93

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My close friends N54 Unfortunately spun a Crank hub yesterday, The cherry on top was that i was driving....

The car is Rwd and manual, has FBO+inlets running 17psi through daw stage 2's, on a E50 tune with 8*'s of timing in it. This was the 5th pull maybe on this map. Before this he was on a safe 14psi pump gas tune. Car has 160k miles on it, no prior work related to the crank hub. Also it has a factory dual mass flywheel.

The events prior to it happening, I was doing a flyby for him so he could record. I slightly brake boosted 2nd, and as i clutched in to go to third the engine died with a unpleasant noise.

Diagnoses so far is that the crank bolt backed out.
So the only thing we know for 100% fact is....
























Your name should be N54_DESTROYER
 

RuskiRacer

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Id Need to have him sign a contract before id let him drive my car. Lots of fine print in the contract as well
 
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RuskiRacer

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Manual transmission cars seem to be the most affected by this issue by a long shot
 

SLOWESTN54

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How though ? I can see with a money shift...but it damn near looked like he was cruising 🤷🏾‍♂️
I believe its the shock factor of when you release the clutch. The torque convertor dampens the shifts in a automatic. Normally the dual mass dampens the the shock in a manual, hence i specified that it has a factory dual mass.
 
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Torgus

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Sucks.

Sorry for you and your friend.

So brake boost in 2nd, go WOT, clutch in to switch to 3rd and it let go? before you got into 3rd and went WOT again? What a PITA. You usually hear about them letting go at higher hp, but it has to be just the shock to make the bolt back out. Stupid BMW design.

I seriously wonder if the https://www.hackengineering.co.uk/product/ked-crank-bolt-capture-plate-n54/ would have helped? I have heard back and forth these do something or nothing.

Sucks all around.
 
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RuskiRacer

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What clutch setup on the car? Oem clutch? Makes me really think the crankhub bolt may have been messed with in the past. Because I'm running a 230k mile motor on 23+ psi on a 6875 and it takes my rolling anti lag hits well and everything. Has to be more hp atleast than the daws maybe not more torque.
 

SlowE93

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Sucks.

Sorry for you and your friend.

So brake boost in 2nd, go WOT, clutch in to switch to 3rd and it let go? before you got into 3rd and went WOT again? What a PITA. You usually hear about them letting go at higher hp, but it has to be just the shock to make the bolt back out. Stupid BMW design.

I seriously wonder if the https://www.hackengineering.co.uk/product/ked-crank-bolt-capture-plate-n54/ would have helped? I have heard back and forth these do something or nothing.

Sucks all around.
Those shits do NOTHING. I've said it over and over again 😡
 

RuskiRacer

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I fail to see how stepping on the clutch "shocks" anything.
I broke 2 axles and would think that creates a bigger "shock" as I was WOT
It wouldn't must've happened before he clutched in and he just noticed it as he clutched in
 
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SLOWESTN54

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Feb 9, 2021
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So brake boost in 2nd, go WOT, clutch in to switch to 3rd and it let go? before you got into 3rd and went WOT again? What a PITA. You usually hear about them letting go at higher hp, but it has to be just the shock to make the bolt back out. Stupid BMW design.
I fail to see how stepping on the clutch "shocks" anything.
It wouldn't must've happened before he clutched in and he just noticed it as he clutched in
I listened closely it definitely went through second fine, when I released the clutch to hit 3rd is when it let go.

@RuskiRacer We'll be pulling the motor this Thursday. Ill let you know what clutch was in it, It couldn't of been stock. You think a stock or a "is" clutch would hold over 500whp for a few pulls?

Luckily we all keep a spare, he's bringing it over tomorrow, car won't be down for long.