Floor Pan Breaking in the trunk?

[BMWLA]

I have heard that the floor pan in the trunk can break with big HP and solid diff mounts. I have some poping going on from the back end when I launch hard :shock:.

Has any one had any breakage back there?

[Rigmaster]

more of an E36/E46 problem.

I'm sure it's possible in an E30, especially with an M5X/S5X swap- but it's not exactly a common problem. Shouldn't be too hard to fix/reinforce unless you let it go too long before you try to fix it.

[FredK]

I think Stu had a problem in his S50US swapped car, after tens of thousands of miles. He welded and reinforced the area. I don't think he was running a solid diff mount, though.

[DCColegrove]

The rear diff mounting point at the body is kind of like a paint can lid...

Breakage isn't such a problem yet... (that I've seen)

However the flex certainly isn't a good thing...

Mason and I are actually working on addressing the issue right now with a modified rear brace "system" that will also reinforce the trunk floor.

We'll probably have it out in several months...