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E46 M3 (2001-2006) Engine: S54 - Max Hp: 333 hp at 7,900 rpm / 262 lb/ft at 4,900 rpm
Total Produced: 45,000+ - Years Produced: 2001 to 2006.


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Old Tue, Sep-06-2016, 06:19:48 PM   #41
VinceSE2
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Default ("Subframe") RACP cracking and separation - How common, what models?

I got a little bit more done today.
Heres a pic of a second layer to the left rear mount. My objective is to primarily add material where the failures occur, and to obtain a digressive plate thickness towards the perimeters. There will be epoxy between the layers, and rivets to clamp them together, as well as tie the plate layers to the bases of the threaded receivers.



This picture shows how I've made a small indentation to make the inner layer sit tight against the indentation of the RACP. There will then be a rivet tying into the mounting point of the threaded receiver (to which the spot welds attach on post feb 2000 built E46's).



Here's a pic of the spot welds mentioned above.






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Old Tue, Sep-06-2016, 08:39:25 PM   #42
slater
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Default Re: ("Subframe") RACP cracking and separation - How common, what models?

awesome, vince!

is the goal for the rivets to replace the spot welds? (i.e., we drill out the spot welds and rivet the plates to the RACP in those holes?)

peter
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Old Wed, Sep-07-2016, 09:44:02 AM   #43
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Default Re: ("Subframe") RACP cracking and separation - How common, what models?

Quote:
Originally Posted by ninertriplezero View Post
Vince, I'm definitely going to get these and pair them with your bar/gusset kit. Awesome work. It's a lot of fun watching your dev work in progress.

I have a question that may be obvious, but I'm new here so I'll ask it... Would any hairline cracks/ broken spot welds all need to be repaired via welding before your kit(s) are applied?

Just realized I never responded to the spot weld part of your question.

I'll be drilling the appropriate size rivet hole in the center of any popped spot weld. And add a 4,8mm rivet with washers to replace the popped spot weld. That way there won't need to be any welding done during a epoxy/rivet installation.

The two popped spot welds in the upper right corner of this picture are good examples of spot welds I'll be riveting later on.



Quote:
Originally Posted by slater View Post
awesome, vince!

is the goal for the rivets to replace the spot welds? (i.e., we drill out the spot welds and rivet the plates to the RACP in those holes?)

peter

No, not really. I'll be saving any and all spot welds that aren't popped or damaged, and try my best to get the rivets in between spot welds (if there are any spot welds near by).




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Old Wed, Sep-07-2016, 09:21:06 PM   #44
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Default Re: ("Subframe") RACP cracking and separation - How common, what models?

And so the first VincePlate set is installed!










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Old Thu, Sep-08-2016, 06:32:00 AM   #45
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Default Re: ("Subframe") RACP cracking and separation - How common, what models?

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Originally Posted by forzanerazzurri View Post
I think based on all the evidence and given how old the cars are getting its safe to assume you have cracking until proven otherwise. Its just crazy that something this serious was missed in the engineering and development of the car. I mean the ability for the RACP to withstand the demands of the car should be a pretty low level requirement for any car company.
Well said.

It's indeed quite ridiculous.
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Old Thu, Sep-08-2016, 07:18:50 AM   #46
VinceSE2
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Default Re: ("Subframe") RACP cracking and separation - How common, what models?

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Originally Posted by RYM3 View Post
Well said.



It's indeed quite ridiculous.


I also fully agree.
Here's a picture I've been working on to help explain the design flaw. I'll soon be adding it, along with explanatory text, to post #1




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Old Fri, Sep-09-2016, 06:28:25 PM   #47
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Default Re: ("Subframe") RACP cracking and separation - How common, what models?

Quote:
Originally Posted by forzanerazzurri View Post
I think based on all the evidence and given how old the cars are getting its safe to assume you have cracking until proven otherwise.
Absolutely. The sticky threads indicating otherwise are out of date, but the older thinking for now seems too stubborn to acknowledge the newer findings.

I had mild visible cracking but once the floor was adequately revealed there were loads of small failures.

Quote:
Originally Posted by forzanerazzurri View Post
Its just crazy that something this serious was missed in the engineering and development of the car. I mean the ability for the RACP to withstand the demands of the car should be a pretty low level requirement for any car company.
I disagree here slightly. I assume the engineers at bmw are probably top notch.

The receivers are not directly connected to the frame rails ON PURPOSE. Why?
A simple theory is they had a competing design mandate that conflicted with making a stronger floor/load path.
Secondly testing is often the first to get sacrificed when a deadline is fixed.

The front shock tower area is another potential failure point that most I've engaged seem to be ok with ignoring. I'm not though.
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Last edited by jdev; Fri, Sep-09-2016 at 06:41:34 PM.
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Old Mon, Sep-12-2016, 03:04:15 AM   #48
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Default Re: ("Subframe") RACP cracking and separation - How common, what models?

Quote:
Originally Posted by VinceSE2 View Post
And so the first VincePlate set is installed!
awesome work vince!

how are the other 3 locations coming along?

peter
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Old Mon, Sep-12-2016, 06:54:39 PM   #49
VinceSE2
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Default Re: ("Subframe") RACP cracking and separation - How common, what models?

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Originally Posted by slater View Post
awesome work vince!



how are the other 3 locations coming along?



peter


Thanks! And thanks for asking, here's a couple of pictures of the current status.

The first layer of the right rear mount:



And the first layer of the left front mount:



I'll hopefully have some more to share tomorrow.


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Old Mon, Sep-12-2016, 07:11:02 PM   #50
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Default Re: ("Subframe") RACP cracking and separation - How common, what models?

that's spectacular, vince - thanks! REALLY looking forward to the progress!
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Discussing ("Subframe") RACP cracking and separation - How common, what models? in the E46 M3 (2001-2006) Forum - Engine: S54 - Max Hp: 333 hp at 7,900 rpm / 262 lb/ft at 4,900 rpm
Total Produced: 45,000+ - Years Produced: 2001 to 2006. at BMW M3 Forum.com (E30 M3 | E36 M3 | E46 M3 | E92 M3 | F80/X)