[Tonester]

I finally had a chance to type up this post....

Prior to Super Lap Battle I revamped my car so that it can be 100% for the competition. On the list was to revise front aero, rebuild/Balance Motons, and most importantly repair/reinforce my subframe + bushings.

I got a care package from TMS which included, monoball bushings for the control arm, solid subframe and diff bushings. I quickly went to work and tore the car apart, I dropped the complete rear end to find a pretty severely cracked subframe.

My subframe has been cracked for about a year now and I've been keeping a close eye on it, however it is more severe than I had expected since I could only see a small portion of the crack I wasn't expecting it to be as bad as it is.

Seeing that my car is a 95% track car I wanted to really reinforce the factory subframe, I made custom subframe mounting plates that are a little thicker than ones that you can get on the market. Upon removal of the chassis undercoating we found very light hairline cracks on the crease of the chassis as well as each mounting point on the rear subframe mounts. From there we welded all the cracks and extra welds around the mounting points to prevent further failure later down the line. We also drilled extra holes in the reinforcement plates around the mounting points to spot weld for more penetration between the plate and the chassis.

In between welding/cooling periods we were installing all the bushings we received from TMS. Pressing the subframe bushings in/out was quite a pain, however we shoved all the bushings into the freezer which helped but 1/2 way through you can see the bushing heat up and it would get more and more difficult as you get to the end.

I also did other top secret mods but that info will be released later on. :shifty:

On completion of everything the car felt awesome! I swear the car actually rides better than it did w/ the oem bushings. It could be a combination of the custom work I did along with the monoball bushings for the control arm, the monoball bushing would give the rear spring a more consistent spring rate since it removes the flex from the inner bushing.

Photos:

Cracks!!!



Starting the repair/extra welds



After repair/extra welds



Thicker plates, extra spot welds to the chassis from the reinforcement plate



TMS Goodies



TMS Subframe bushings installed



TMS Monoball bushings



TMS Diff bushings

[Gearhead999s]

Just to be clear is this a E46 or E92 M3?

[IND-Distribution]

Look like an E46 M3 to me.

[008]

My E46 was torn apart after 3 years on the track. Rear subframe but also in the front where the body meets the chassis at the suspension pick up. Welded it which stop the cracking but I don't think they are up to that amount of tracking without constant maintenance and reinforcement. I've always wanted to do solid bushings on my cars but never have. Great mod, maybe the E92 will get some.

[onefastman]

Your teeth will fall out with those bushings

[Tonester]

Originally Posted by onefastman

Your teeth will fall out with those bushings

Actually no, its not as bad as you think.

[aus]

Still waiting on E46 or E92....

[jml]

E46 - pretty obvious from the pics.

[aus]

Do we have the same potential issues given how heavy our cars are?
You'd think BMW would have addressed this in the E46's since it was a problem in the E36 already.

[FStop7]

The E46 had terrible issues with subframe damage. Not likely to be repeated on the E9x - the chassis has been around for so long that it would likely have already surfaced as a problem.

[swamp2]

Come on get with the program...


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