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-   -   Any XIs with subframe cracks ??? (http://forum.e46fanatics.com/showthread.php?t=800682)

Mark M 10-26-2010 10:48 AM

Any XIs with subframe cracks ???
 
Over on M3Forums there are a handful of members dealing with cracked rear subframes. I know they cite the primary causes for rear subframe cracking is abrupt application of power / torque to the rear wheels, like launching the car, and/or worn RTABs.

Wondering if us XI boys have seen any issues? Had the dealer check mine last year and was given a thumbs up, no issues.

Anyone else?

TiAgXi 10-26-2010 10:57 AM

Xi's don't have subframe issues. Only crappy RWD cars have that problem.

Mark M 10-26-2010 02:32 PM

TiAg might not be too far from the truth here. My gut theory is that due to the AWD system, the rear subframe never sees enough torque to cause cracks.

However, conversely, due to the AWD system, our front control arm bushings wear faster due to the torque / power now pulling through the front axles.

Kubica 10-26-2010 04:01 PM

No.

The cause of subframe damage is poor welds that don't hold. Xi's dont have the bad welds, so no subframe issues.

Poor welds are poor welds. It doesn't matter how much/little power the rear wheels get- if the welds are bad, the welds are bad. You either have a cracked subframe, likely to get one in the future, or will most likely never get a cracked subframe.

Luckily all xi's fall into the third category, as do most e46's. It's the welder that determines if your car has potential subframe damage. E46's without poor welds won't have subframe issues. E46's with poor welds either have a cracked subframe, or the possibility of one in the future. Adding more power to a car with good welds isn't going to cause subframe damage. On the other hand, adding more power to a car with bad welds most likely increases the chances your subframe will crack.

Make sense?

xi_ter 10-26-2010 04:59 PM

The main difference is that there is a transfer case right in the middle of the car between the 2 drive lines. This stiffness between the front and rear differentials prevents the subframe movements in the RWD that cause the failures. Take a look under your xi and you'll see the strength from building the drivetrain this way.


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