E36 Safety and IT

[europeanspec]

The "modifications" he is talking about is to keep the sub-frame, shock towers and strut towers from tearing out of the car. I guess you could wait until they fail, but that is ridiculous. With the M3, BMW fixed the problem. The repair pieces are available through BMW. They don't provide any advantage other than being able to keep the tub from coming apart.

Are you allowed to fix a chassis or do you have to throw it out when something happens to it?

[lateapex911]

So the whole thing just rips out and ends up at teh side of the road at once!?

[Xian]

You can fix the chassis in accordance with factory repair methods. FWIW, many Honda products have problems with the rear subframe tearing out too... we just inspect it regularly and fix it when it happens.

[Ron Earp]

It seems that about every twelve months the E36 subframe debate pops up.

[seckerich]

Never saw a tear in metal that could not be fixed with a simple tig weld. Legal and strong without the drama. Drill a 1/8 inch hole at the end of the crack and fill as needed. Every part on a race car should have a life cycle and get replaced before it breaks.

[dyoungre]

Isn't there a documented service procedure for E36s that instructs technicians to repair the subframe mounting location cracks? If so, I would think it would therefore be an accepted reinforcement,IF the repair procedure were provided at a prtest or inspection

[JLawton]

Isn't there a documented service procedure for E36s that instructs technicians to repair the subframe mounting location cracks? If so, I would think it would therefore be an accepted reinforcement,IF the repair procedure were provided at a prtest or inspection

Everytime this discussion comes up (once a year??), the BMW guys say that reinforcing is the proper official BMW repair procedure for this problem.......... but we have yet to actually see any documentation..........


.

[Doc Bro]

So the whole thing just rips out and ends up at teh side of the road at once!?

Kinda...

Last year at NHMS Dave hit some Oil Dry in Nascar 1&2 in his e36, and lost traction, then regained traction with a quick slide ocurring. On corner exit he knew something had happened beyond the loss of grip. He immediately pulled the car in. Dan immediately checked the subframe mounts and noticed a crack. Loaded the car and called it a weekend. When Dan put the car on the lift he noticed it had ALL cracked, including breaking the trans mounts and the motor mounts....literally ripped the driveline out of the car. Took him a week to fix......how's that for a failure from Oil Dry?

R

[Greg Amy]

...how's that for a failure from Oil Dry?

I HIGHLY doubt all that damaged was caused in that one moment; the amount of stress needed to rip sheet metal to that magnitude in one instant is absurdly immense, far more than even the vaulted awesomeness of a BMW can generate (even without the SIR ). I'm much more likely to believe that this damage had been propagating for quite some time, with a small crack fatiguing and growing to the point where a minor incident as you describe finally allowed it to break across a critical area.

Sounds more like lack of adequate on-going inspection of a critical safety area, to me.

GA

[Doc Bro]

I HIGHLY doubt all that damaged was caused in that one moment; the amount of stress needed to rip sheet metal to that magnitude in one instant is absurdly immense, far more than even the vaulted awesomeness of a BMW can generate (even without the SIR ). I'm much more likely to believe that this damage had been propagating for quite some time, with a small crack fatiguing and growing to the point where a minor incident as you describe finally allowed it to break across a critical area.

Sounds more like lack of adequate on-going inspection of a critical safety area, to me.

GA

While what your saying makes sense I doubt highly it's true. The e36 we're talking about is METICULOUSLY prepped and maintained. That car has more nut & bolt jobs done to it than the rest of the ITR field combined, and is constantly on the lift or alignment machine.

When the subframe mounts go (and there aren't that many of them) they go quick....BMW motor mounts are made of paper mache- I don't think that grand scale Newtonian force is necessary to cause serious damage.

R

[Greg Amy]

Rob, sheet metal failures like this are due to fatigue, something that happens over many cycles, not catastrophically. Just as it's impossible for you to pull apart a paper clip with your bare hands, you can easily break one apart by bending it several cycles, starting a crack, and then it comes apart.

It's simply not possible that this car's subframe/chassis/sheet metal failed all of a sudden due to driving through oil dry and then catching grip. No way. What this means is, regardless of meticulousness of prep (and I know who you're talking about, and I'm aware of their reputation, ad I agree with you), a chassis crack was missed during inspection and that crack was allowed to propagate to the point of failure...

If we were to consider these kind of items "safety concerns" and thus deserved of special treatment/mods, then we open the Pandora's Box of just about any parts subject to failure being allowed to be improved. Just ain't gonna happen. - GA