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Thread: e46 M3 control arm failure / Saturday Laguna race vid

  1. #1
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    e46 M3 control arm failure / Saturday Laguna race vid

    Here's two pics of the culprit.

    You can see it sheared where the taper begins. The control arms were replaced in January, 2005, so went through the '05 and '06 seasons (approx. 15 events) and three this year (2 races, 1 test weekend.) Never on slicks -- always Hoosiers or Toyos.

    Will most definitely respect the 2-season policy for CAs moving forward...

    ; )

    Car is fine -- mangled splitter and 1 cut up Hoosier from getting dragged through the litter at 11.





    Race vid here:

    http://m3ma420.com/BMWCCA.2007.4.21.wmv

    -Mike

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    How many miles were on this component (race and street if applicable)? You said Approx 17 events, do we assume 3 sessions per day, and 2 days per event?

    When was the bolt last torque/checked?

    It seems from the video you bottomed out on the rumble strips and possibly damaged the control arm at that time, and the braking force pushed it past its limit and it full sheared. I don't think this was from wear/tear, I think it was damaged physically and caused the premature failure.

    Looked like a ton of fun otherwise though, definitely one of the tracks i'd like to hit-up when/if I wenture out there.

    Also, what Lollipop bushing are you using?

    This is an example though that might prove worthy to make a custom outer ball joint.

  3. #3
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    Unreal Mike, did you kiss the wall? Thanks for sharing the vid!

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    He did not hit the wall. He was very lucky the failure occurred where it did at Laguna. If I had to choose where I was going to have a failure like that, that's about the only place at Laguna I'd choose.

    I'm glad you got lucky, Mike.....that could very easily have destroyed your car and put you in serious danger.

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    Awesome video.....except for that ending. But that was a nice save to keep it off the wall.
    Last edited by ///M3Matt; 04-24-2007 at 05:29 PM.

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    Quote Originally Posted by Steve J. View Post
    How many miles were on this component (race and street if applicable)? You said Approx 17 events, do we assume 3 sessions per day, and 2 days per event?
    Let's say 20 events, or 40 days of 4 x 30 min. sessions on average. (Prac / Prac / Qual / Race) or 'testing' sessions...

    Average the four most used tracks - Sears, Laguna, T-hill and Buttonwillow at 2.75 miles?

    There's a good approximation of your milage...

    Quote Originally Posted by Steve J. View Post
    When was the bolt last torque/checked?
    Assume you are talking about the 20mm and 18mm locknuts? Checked every post-weekend inspection and usually every pre-race setup.

    Quote Originally Posted by Steve J. View Post
    It seems from the video you bottomed out on the rumble strips and possibly damaged the control arm at that time, and the braking force pushed it past its limit and it full sheared. I don't think this was from wear/tear, I think it was damaged physically and caused the premature failure.
    It's possible the CA was damaged prior but FWIW there have been much rougher bounces in other races, etc. so I'd say the average dedicated-racecar e46 M3 control-arm lifespan might be two seasons...

    Quote Originally Posted by Steve J. View Post
    Also, what Lollipop bushing are you using?
    Standard Jay Morris issue.

    Quote Originally Posted by Steve J. View Post
    This is an example though that might prove worthy to make a custom outer ball joint.
    Absolutely, although in my case that'd be way down on the list...

    ; )

    Keep us posted on your progress.

  7. #7
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    great video......crazy ending.... WOOO WOOO WOOOO

    Element Tuning - 2008/2009 NJMP Redline Time Attack/Formula X Champions [Street & Modified]
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    Well, there are other issues known in that area of the suspension. Rolex motorsport fronts had to have the upright/hubs modified with a weld in gusset where the stud for the outer ball joint was, as it was shown to fail.

    When you checked those nuts you did not torque them extra correct, you just did a bolt check?

    I wonder if possibly it was from repeated re-torquing, and it caused a straight shear from stress through the hub onto the base of the ball joint/studs, I don't know there could be tons of explanations. However, I think that hit at the beginning is most likely the culprit.

    Unfortunately, its not the easiest thing to convert that balljoint to a "race" component, might just be easier to bite the bullet and replace the arm every other season,or maybe every season if you race a LOT like those lucky westcoasters Damn 12month nice weather!

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    Quote Originally Posted by Steve J. View Post
    I wonder if possibly it was from repeated re-torquing, and it caused a straight shear from stress through the hub onto the base of the ball joint/studs, I don't know there could be tons of explanations. However, I think that hit at the beginning is most likely the culprit.
    Steve, you bring up a good point. Some other folks have also wondered if the nut was over-tightened. The spec for the spindle-nut is 42 lbs., and while I checked precise torque every once in awhile, it is possible that during my normal maintenance the nut was tightened to more than 42 lbs.

    At any rate, I am implementing a 2-season policy for the CAs, moving forward.

    I would assume guys running slicks w/ OEM CAs will want to change them out at least once a season, if not twice?...

    Scott Lang -- believe you me you me it could've been disastrous. Hence the Hoo-ing in the vid!...

    ; )

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    Quote Originally Posted by 2pups View Post
    Scott Lang -- believe you me you me it could've been disastrous. Hence the Hoo-ing in the vid!...

    ; )
    LOL, didn't hear that, I watched with the sound turned down....didn't want the underlings at the office to think I was sitting around watching racing videos....sets a bad example....

  11. #11
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    nice vid, really enjoyed your comentary.
    Matt Williams -
    Current - 01 LSB M3
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    95 Alpine White/Yellow M3 - Stock, except for the stuff that isn't




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    What is the production date stamped on the failed control arm?



    I don't use them but I'm wondering if it could not also be a bad batch of ball joints due to poor steel. Hence a bad batch of control arms.

    I had a similar failure on my 7 , just 3minutes of driving time following a track event.

    m

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    If it makes you feel any better my front control arms lasted just the week-end at VIR with 280 slicks on the front. Last year they were changed twice during the season.

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    Quote Originally Posted by Gread View Post
    If it makes you feel any better my front control arms lasted just the week-end at VIR with 280 slicks on the front. Last year they were changed twice during the season.
    Seriously? Wow. That's scary.

    You know who to talk to. The RRT E36/E46 control arm setup with spherical bearings and hardened bolts never gave us any problems in two seasons. Either that, or you need some of the tubular arms that they are developing on our car.

  15. #15
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    Quote Originally Posted by mmark. View Post
    What is the production date stamped on the failed control arm?

    I don't use them but I'm wondering if it could not also be a bad batch of ball joints due to poor steel. Hence a bad batch of control arms.
    That seems to me like a typical failure of a BMW control arm. That tapered down area is a stress riser. Is it not Steve? or other engineers.

    The E30/E36 arms typically fail at the inner ball joint though, this E46 one failed at the outer. Good to know it didn't cause too much damage.

    Carlos.

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    How often are GAC GS E46 M3 teams changing front arms?

  17. #17
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    I have always seen the same inner joint failure the arms are known for anyway. It has never been in an issue because Turner is religous about the upkeep of my car and sees this problem on all of the serious track cars. I am seeing it more frequently now due to the increased amount of front grip generated.

    Bryan, the one issue I have about getting a custom front system from RRT, Evosport or Turner is liability. I spoke with all 3 companies about getting involved with "re-engineered" suspension pieces. I like Barry, Brad and Will enough to caution them about selling upgraded pieces to the public. We all know racing is horrendously expensive and regular maintenence is something that easily gets overlooked in the budget. If these guys offer a part and it fails causing serious injury or death a court will find them liable when sued. BMW can get away with it because they have never implied the part was sufficient for a racing application. A third party fix implicates the shop as taking the responibility for a stated or implied racing application and in todays crazy US legal system, liable for damages caused by it's failure. It's fine for RRT/Evosport to use their own parts on their own car, but I have cautioned them about selling it to the public even if I could benefit from it.

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    Quote Originally Posted by Gread View Post
    Bryan, the one issue I have about getting a custom front system from RRT, Evosport or Turner is liability. I spoke with all 3 companies about getting involved with "re-engineered" suspension pieces. I like Barry, Brad and Will enough to caution them about selling upgraded pieces to the public. We all know racing is horrendously expensive and regular maintenence is something that easily gets overlooked in the budget. If these guys offer a part and it fails causing serious injury or death a court will find them liable when sued. BMW can get away with it because they have never implied the part was sufficient for a racing application. A third party fix implicates the shop as taking the responibility for a stated or implied racing application and in todays crazy US legal system, liable for damages caused by it's failure. It's fine for RRT/Evosport to use their own parts on their own car, but I have cautioned them about selling it to the public even if I could benefit from it.
    Now that's a pretty extreme stance for someone who owns and runs a 500 whp race car.

    So, in your opinion, every company that puts their name on an adjustable rear lower control arm is taking a big risk? Or do you only see a problem with "modifying" BMW suspension pieces?

    Given the choice between worrying about my front control arms failing at speed if I don't replace them between every race and the option of having something that is more reliable and safer, I'm glad their are companies willing to take the risk to design and offer better suspension pieces for my race car. I'd rather crash knowing I had the best equipment I could rather than crash because I was running something that was never up to the task to begin with.

  19. #19
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    Greg, you can use that argument towards anything though...as you said, you can sue for anything. Whether its a busted pedal or failed wheel, you can argue the same for each.

  20. #20
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    Greg, What happens if your motor throws a rod, oils your tires and you crash? Same thing as a suspension part breaking. Should we all just run stock BMW parts on our cars???

    -tony
    Tony Colicchio
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    Motion Control Suspension factory authorized repair and rebuild facility, suspension design, set-up and parts fabrication. Rollcage, rollbar and chassis fabrication and repair.

  21. #21
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    It happens with stock/oem parts too. What do you think Recalls come from

  22. #22
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    I only caution because I have been sued in a similar situation and lost. The engine issue can be argued against having direct relationship with the safe handling of the vehicle. I understand people offer various pieces as upgrades and I use these without issue. I would use the RRT without issue on the front, but I have a competent shop completely review the vehicle after every event. Bryan and some of the other top contenders understand the requirements of running a top notch vehicle safely, but there are other people out there who don't and fail to give the time and resources necessary to protect themselves and others. I love the support the small outfits such as TC, RRT, Evo and Turner provide us who are willing to be responsible with the equipment and I would hate to see their good intentions cost them everything. Manufacturers have large legal teams and plenty of precedent standing in their pocket, the little guy does not.
    I wish I had 500 whp...

  23. #23
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    Quote Originally Posted by Gread View Post
    I wish I had 500 whp...
    That was the # circulating around the paddock. You and Stickley both disappear on the straights at a rate so fast that it's impossible to tell who has more power.

  24. #24
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    Greg, I hear you and fully understand what you are saying. Having said that, should I just take up knitting?

    -tony
    Tony Colicchio
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    Motion Control Suspension factory authorized repair and rebuild facility, suspension design, set-up and parts fabrication. Rollcage, rollbar and chassis fabrication and repair.

  25. #25
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    Could you post a closeup pic of the failed area of the stud? Hopefully the failure surface hasn't been molested too bad.

    Do you manage to find/keep the mating part. It may be possible to tell the failure mode.

    Also, threads = stress risers. Hopefully they are rolled.

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