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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 Thu, Jul-27-2017, 06:23:52 PM   #11
Kdubski
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Default Re: Subframe reinforcement difficulty

Thanks for the input guys. I figure my uncle's shop can get it done in 2-3 days tops on the lift. The only downside is they're not E46 connoisseurs, so they would fix the cracks, install the plates, and replace the bushings, and install the vincebar,but not all the little extra welds a BMW indy shop might.
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Old Fri, Jul-28-2017, 05:13:29 AM   #12
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Default Re: Subframe reinforcement difficulty

Hey Kdubski,

Sorry to hear you've discovered the cracks.

Have you got an photo's showing the severity of the damage? It can help determine what to expect and where you may find damage.

Looks like everyone is on the money, stop drill the ends of the cracks, weld them shut, grind them smooth and get some quality repair plates weld in. A good top side reinforcement is also the key for longevity.

Quote:
not all the little extra welds a BMW indy shop might
I thought I'd chime in and share some photo's of my own car when I repaired it to help explain where to look and have repaired to ensure the job is done correctly.

As you mentioned, you've discovered the rear left which (from my experience) is the equally as common as the front right. Here's how I found mine;





The next most common spot is generally the rear left wheel arch. It often initiates directly behind the dampener.

To repair this area the spot welds will need drilling and re-welding and I would recommend putting small stitch welds along the overlap on the outer face to strengthen this join.





I'm afraid I don't have any photo's of the next spot however, once the wheel arch join lets go it is not uncommon for the carrier panel to begin separating from the chassis rails. The best spot to look is the left chassis rail on the furthest back section of the flat part behind the rear seats.

You'll often find a variety of spot welds beneath the car have failed. Often either side of the wheel well just behind the subframe mounts among a variety of other places.

lastly, I just want to mention three other areas worth inspecting/ having repaired despite them not being visible without some cutting.

1, top welds of front two, rear subframe mounts. These are found beneath the rear seats. You will need to cut away a small area of sheet metal to expose them however, they are relatively common to crack once things get pear shaped underneath.

A fellow who did a bolt method repair detailed how to accurately locate them. I can look it up if you'd like?





2, I also recommend inspecting the top of the carrier panel which is beneath the curve section in front of the wheel well. I can dig up a larger picture of how to removed that sheet metal if you'd like?

This should be made visible during the installation of a top side support.

Essentially this crack initiates form a failed spot weld and has proven to be relatively common yet often missed.



Lastly, it's a fairly recent and uncommon issue however, having checked my own car as well as a friends while doing a RMS style underside resto, I found a small failure on the inner most edge of the RTA cup.

It likely will need cleaning to expose it however, it isn't too uncommon to find something like this.



I would recommend putting a small weld bead around the perimeter of each radius and repair any spot welds if they have popped.

It may not appear major however, one member hear experienced catastrophic failure to his race car and I believe it's worth doing if it has any potential at all of occurring. I'd hate to imagine how a street car on a track day would fair in comparison.

I hope he doesn't mind me sharing some photo's put on the forum however, this is how he found it. You can see that the spot welding holding the cup in popped and it simply fell away still intact and bolted together.





If you address all the above you should have a repair equal to or better than the majority of specialists could provide.

If you are after a top side support, I also manufacture one.

It is not hidden like Vince's however, in exchange is more rigid.

The kit picks up all 5 of the factory MIG welds holding the female threaded insert for the subframe mount within the carrier panel and ties into all spot welds down the length of the chassis leg resulting in ideal integration into the existing structure.
The chassis rails are a sandwich of more than one layer and by picking up the stress at the intended structural links rather than welded to the sheet metal around them, eliminates the potential for new stresses between these links in both the carrier panel an down the chassis leg.

The kit overlaps the entire top face of the carrier panel's rear mounts as well as the hidden crack (#2) detailed above to reinforce this area to compensate for fatigue and further increase rigidity.

If you're interested feel free to PM me. I sell the kit for ~$425 USD ($535 AUD) at current exchange rate + shipping.



Either way, let me know if there is anything I can do to help.

Last edited by AussieE46M3; Fri, Jul-28-2017 at 05:22:33 AM.
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Old Fri, Jul-28-2017, 01:15:07 PM   #13
Drewster
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Default Re: Subframe reinforcement difficulty

Quote:
Originally Posted by Kdubski View Post
Thanks for the input guys. I figure my uncle's shop can get it done in 2-3 days tops on the lift. The only downside is they're not E46 connoisseurs, so they would fix the cracks, install the plates, and replace the bushings, and install the vincebar,but not all the little extra welds a BMW indy shop might.
I would trust folks that I know, have some relationship with, and know how to weld far more than a "BMW indy shop"

Good luck - at least you caught it!
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Old Fri, Jul-28-2017, 09:16:22 PM   #14
90mtx
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Default Re: Subframe reinforcement difficulty

I just epoxied the VinceBar and VinceSkins in and it is fairly straight forward and easy. I did it in a two car garage on jack stands. Once you have all your tools, parts, supplies etc. You could get it done in over two weekends. Your results will vary of course, but if you are comfortable doing DIY stuff, go for it. You will cut your car for VinceBar, but once you get over that and measure more a few times and think about it you are good to go.

Jonathan
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Old Sat, Jul-29-2017, 03:19:14 AM   #15
AussieE46M3
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Default Re: Subframe reinforcement difficulty

If you've got cracks you'll want to weld them up before you put any plate system over the top.

Without closing the cracks, the panel cannot transfer stress as there's a literal gap in the load path. The skin would be isolated and the rivets would be under shear stress trying to elongate the holes and potentially initiate additional cracks.
Given the skin is thinner than the original structure and not uniform, I can't imagine it would fare any better if the cracks are not correctly repaired. The skin is a localised reinforcement just like any other plate.

To address the cracks and all the other problem areas correctly you're going to need some welding.
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Old Sat, Jul-29-2017, 06:13:55 AM   #16
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Default Re: Subframe reinforcement difficulty

Quote:
Originally Posted by AussieE46M3 View Post
Hey Kdubski,

Sorry to hear you've discovered the cracks.

Have you got an photo's showing the severity of the damage? It can help determine what to expect and where you may find damage.

Looks like everyone is on the money, stop drill the ends of the cracks, weld them shut, grind them smooth and get some quality repair plates weld in. A good top side reinforcement is also the key for longevity.



I thought I'd chime in and share some photo's of my own car when I repaired it to help explain where to look and have repaired to ensure the job is done correctly.

As you mentioned, you've discovered the rear left which (from my experience) is the equally as common as the front right. Here's how I found mine;





The next most common spot is generally the rear left wheel arch. It often initiates directly behind the dampener.

To repair this area the spot welds will need drilling and re-welding and I would recommend putting small stitch welds along the overlap on the outer face to strengthen this join.





I'm afraid I don't have any photo's of the next spot however, once the wheel arch join lets go it is not uncommon for the carrier panel to begin separating from the chassis rails. The best spot to look is the left chassis rail on the furthest back section of the flat part behind the rear seats.

You'll often find a variety of spot welds beneath the car have failed. Often either side of the wheel well just behind the subframe mounts among a variety of other places.

lastly, I just want to mention three other areas worth inspecting/ having repaired despite them not being visible without some cutting.

1, top welds of front two, rear subframe mounts. These are found beneath the rear seats. You will need to cut away a small area of sheet metal to expose them however, they are relatively common to crack once things get pear shaped underneath.

A fellow who did a bolt method repair detailed how to accurately locate them. I can look it up if you'd like?





2, I also recommend inspecting the top of the carrier panel which is beneath the curve section in front of the wheel well. I can dig up a larger picture of how to removed that sheet metal if you'd like?

This should be made visible during the installation of a top side support.

Essentially this crack initiates form a failed spot weld and has proven to be relatively common yet often missed.



Lastly, it's a fairly recent and uncommon issue however, having checked my own car as well as a friends while doing a RMS style underside resto, I found a small failure on the inner most edge of the RTA cup.

It likely will need cleaning to expose it however, it isn't too uncommon to find something like this.



I would recommend putting a small weld bead around the perimeter of each radius and repair any spot welds if they have popped.

It may not appear major however, one member hear experienced catastrophic failure to his race car and I believe it's worth doing if it has any potential at all of occurring. I'd hate to imagine how a street car on a track day would fair in comparison.

I hope he doesn't mind me sharing some photo's put on the forum however, this is how he found it. You can see that the spot welding holding the cup in popped and it simply fell away still intact and bolted together.





If you address all the above you should have a repair equal to or better than the majority of specialists could provide.

If you are after a top side support, I also manufacture one.

It is not hidden like Vince's however, in exchange is more rigid.

The kit picks up all 5 of the factory MIG welds holding the female threaded insert for the subframe mount within the carrier panel and ties into all spot welds down the length of the chassis leg resulting in ideal integration into the existing structure.
The chassis rails are a sandwich of more than one layer and by picking up the stress at the intended structural links rather than welded to the sheet metal around them, eliminates the potential for new stresses between these links in both the carrier panel an down the chassis leg.

The kit overlaps the entire top face of the carrier panel's rear mounts as well as the hidden crack (#2) detailed above to reinforce this area to compensate for fatigue and further increase rigidity.

If you're interested feel free to PM me. I sell the kit for ~$425 USD ($535 AUD) at current exchange rate + shipping.



Either way, let me know if there is anything I can do to help.
Would you say your reinforcement is easier to install than the vincebar installation?
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Old Sat, Jul-29-2017, 10:03:55 AM   #17
AussieE46M3
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Default Re: Subframe reinforcement difficulty

Hey M3 Pilot,

Quote:
Would you say your reinforcement is easier to install than the vincebar installation?
I would not say it is easier however, I would not say it's a whole lot more work either.

It requires a little bit more welding as it has to be installed in a set sequence. both need the same amount of cutting, prepping and preliminary welding prior to installation.

If you're interested, the installation manual is available online in PDF format. I've shared the link below. Basically the first 9 steps are identical however, differ from there onward.

http://cmpautoengineering.com/wp-con...l-Manual-2.pdf

I don't want to accidentally hijack someone else's post. If you have any questions about the kit or installation please feel free to PM me or inbox me on facebook. I'm generally much sooner to respond there so I'll include a link for that below.

Also, if anyone wants more information I'm always willing to help where I can. I'm open to giving input and discuss how best to approach the issue if you'd like. Feel free to contact me and I'll do my best to get back to anyone.

https://www.facebook.com/cmpauto/

I understand installing such a kit may not be cheap if outsourcing the fabrication. I have had it suggested in the past that I should make it a single pre-fabricated kit to speed up the install however, it's not possible to achieve the same level of integration and load distribution if it were.
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Old Sat, Jul-29-2017, 03:13:18 PM   #18
M3_Pilot
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Default Re: Subframe reinforcement difficulty

Quote:
Originally Posted by AussieE46M3 View Post
Hey M3 Pilot,



I would not say it is easier however, I would not say it's a whole lot more work either.

It requires a little bit more welding as it has to be installed in a set sequence. both need the same amount of cutting, prepping and preliminary welding prior to installation.

If you're interested, the installation manual is available online in PDF format. I've shared the link below. Basically the first 9 steps are identical however, differ from there onward.

http://cmpautoengineering.com/wp-con...l-Manual-2.pdf

I don't want to accidentally hijack someone else's post. If you have any questions about the kit or installation please feel free to PM me or inbox me on facebook. I'm generally much sooner to respond there so I'll include a link for that below.

Also, if anyone wants more information I'm always willing to help where I can. I'm open to giving input and discuss how best to approach the issue if you'd like. Feel free to contact me and I'll do my best to get back to anyone.

https://www.facebook.com/cmpauto/

I understand installing such a kit may not be cheap if outsourcing the fabrication. I have had it suggested in the past that I should make it a single pre-fabricated kit to speed up the install however, it's not possible to achieve the same level of integration and load distribution if it were.
Awesome, thanks.
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Old Sat, Jul-29-2017, 09:30:04 PM   #19
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Default Re: Subframe reinforcement difficulty

Vincebar is a separate project than plates/cracks.

You need to drop the assembly, fix the cracks and weld in some plates. Bushings as well if you like. Then you'll have your car back in running order and can do Vincebar whenever.
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Old Tue, Aug-01-2017, 12:43:22 PM   #20
90mtx
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Default Re: Subframe reinforcement difficulty

Not to away from the OP question about the level of difficulty, but to the OP do your research on welding vs epoxy. Each has people that swear by each and strong detractors of the "other" one. There is more than one way to fix the inherent design issue if the E46 chassis. Your car, your choice bit look in to the differences yourself.

Jonathan
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Discussing Subframe reinforcement difficulty 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)