Subframe Dropped and cracks found

[VinceSE2]

Mybe Im playing devil's advocate here, id like to see the extent of damage after plates are done and foam. I haven't been able to pull up any examples mysefd, maybe someone can post some links?

Although I’ve learnt over the years that sometimes all the facts and evidence in the world is not enough, here’s an old archived thread of mine from m3f that explains this very well.

It contains at least 5 examples of cars that, even though they have been plated (foam makes no technical difference as it strengthens the same area as plates), have failed just like I have described.

Please be aware though that this takes a while to load as it’s in some sort of archive.
So anyone interested in reading it, PLEASE BE PATIENT
Also, it won’t open inside of Tapatalk

https://web.archive.org/web/20170731214304/http%3A//www.m3forum.net/m3forum/showthread.php?t=555302

Sent from my iPhone using Tapatalk

[VinceSE2]

Tried pasting the content from the archive here, but no pictures come through.

But here’s one I copied to show you where the foam goes. And hopefully you’ll understand why it makes no difference




And here are two pictures that clearly show cracks and chassis separation on two different cars that where plated

[pawelgawel]

Thank YOU! appreciate all this info

[martin.oconnor]

Although I’ve learnt over the years that sometimes all the facts and evidence in the world is not enough, here’s an old archived thread of mine from m3f that explains this very well.

Sorry - but this is not 'all the evidence in the world'.

The question is not that this type of failure can occur - it is how likely is it to occur.

When I was deciding which subframe strengthening strategy to go with back in 2016-2017 I looked for evidence that this failure mode was common. I found just a smattering of reports (in contrast to reports of mount failures, which are legion). Many of these cars are approaching 20 years old now and if this were a common failure mode E46 forums would be overrun with reports. So I decided to use foam on the four mounts.

The cost/possible-benefit ratio of the above approach seemed well beyond reasonable for me, particularly given the invasive nature of the solution and reliance on the skills of the person installing it.

The notion that all E46 M3s are ticking timebombs that will eventually exhibit this failure model seems to go well beyond the empirical evidence.

[Tbonem3]

Agreed Martin.

I've been around a while, and all of the big 3 are overblown. Hell, even the cars with broken vanos exh hub tabs keep plugging along just fine. Intake bolts shearing or working loose is uncommon as well, and only afflicts 05/06s as far as I can tell. Way more 200k cars with original bearings than sub 100k with spun ones. Very very few reports of RACP issues after plates/bushings job - and even then we don't know how well the job was done in those cases. And at this point, it's not a case of "well, not enough time or miles have passed for us to know yet."

It's like people claiming COVID is deadly because the news says so and their over weight, diabetic uncle died. Reality is different than perception.

[lemoose]

It's like people claiming COVID is deadly because the news says so and their over weight, diabetic uncle died. Reality is different than perception.

Not sure what news you're watching/reading that is trying to convince you that the virus is definitively going to kill you. The main narrative I've gotten is that we don't have the infrastructure to reliably deal with .1-1% of the entire population being hospitalized for the same thing within a sub-12 month timeframe.

[enjoy_m3]

Well, here is how I found out about my problem.

https://www.youtube.com/c/RedishMotorsportbmw/videos

You'll have to scroll through the older videos which they do explain failure points on the e46 chassis that Vince was also mentioning. They actually say all e46 chassis have this issue. They have a lot of videos with different varying types of failures on the e46. They're the only shop I know of that are doing this kind of extensive repair/restore on RACP.

I had reinforced subframe done by Kevin (kaiv). Took the car a couple of track days and upon pre-track inspection, I found small crack in the seam sealer. That's when I decided to get the vincebar and found the reddish motorsport videos.
And out of curiosity, I took off the seam sealer in the areas Reddish mentioned. There wasn't any visible damage until I took out the seam sealer and found the failed spot welds. I guess the only way to really find out if you have the issue is to remove the seam sealer in your car if you're willing to.

[t3ddftw]

holy hell, at basic shop rates of $100/hr this is sounding more like a $5k job than the $3k I was kinda planning on. curious if others who have had this done have any feedback?

I'm about $2000 into this project doing everything except the welding. This price includes replacement bushings and balljoints for everything in the rear subframe.


My 2006 with 100,040 miles zero cracks and one spot weld failure (located on the topside of the RACP).

I installed the CMP plates along with their "Stage 1.5" plates which similarly to the Redish V3 tie the chassis legs to the RACP without a cross bar.

-Ted

[jet_dogg]

Agreed Martin.

I've been around a while, and all of the big 3 are overblown. Hell, even the cars with broken vanos exh hub tabs keep plugging along just fine. Intake bolts shearing or working loose is uncommon as well, and only afflicts 05/06s as far as I can tell. Way more 200k cars with original bearings than sub 100k with spun ones. Very very few reports of RACP issues after plates/bushings job - and even then we don't know how well the job was done in those cases. And at this point, it's not a case of "well, not enough time or miles have passed for us to know yet."

It's like people claiming COVID is deadly because the news says so and their over weight, diabetic uncle died. Reality is different than perception.

I think it will eventually affect all cars produced just at different rates. It's also a case of people not knowing about the internal chassis conditions of their cars. I am of the opinion, however, that the root cause of this is failed subframe bushings percussing against the panel with varying load inputs (and no less because of a loosely mounted differential twisting about its carrier).

Though contrary to forum dogma, I have solid diff bushings going in as well. Monoball everything on the street too.