E70 strut brace.

[rh71]

^ so they are strut braces/bars no?

At great risk to myself in waking my kid when grabbing the keys, I ran out to take these pics:

[X5X]

Thats exactly how my engine bay looks like.

[JCL]

Originally Posted by rh71

^ so they are strut braces/bars no?

No, they are not strut braces in the traditional sense, because you don't have any struts to brace on an E70. The 'strut' being referred to in strut braces is a McPherson strut, and the top of it (under the dome) locates the suspension. A strut brace running across the vehicle transversely ties the two of them together to maintain front end alignment under extreme cornering loads.

The two short braces are struts in the generic sense of a strut being a horizontal or vertical support member, in the same sense that you have struts holding up the hatchback, but these struts appear to be strengthening the dash panel torsionally, since they are called 'dome to dash panel struts' as Viperfreak posted.

[rh71]

^ thanks, what about the front bar if that is not "maintaining front end alignment" either?

I can see pics of strut/stress bars on a Z4 here: http://www.bavauto.com/lview.asp?img..._99_85_011.jpg ... mounting points are obviously different. Just curious what the point of our bars are.

[JCL]

Originally Posted by rh71

^ thanks, what about the front bar if that is not "maintaining front end alignment" either?

I can see pics of strut/stress bars on a Z4 here: Bavarian Autosport | Product Closeup ... mounting points are obviously different. Just curious what the point of our bars are.

I am not sure what the front brace is doing specifically, but I imagine it helps stiffen up the front end. That could be for crash impact ratings, to mount some component (like the air duct shown), to stop rattles, or any number of things. Thinking about it, the E70 fenders are totally prefabricated by an outside supplier with the outer and inner fender, lights, etc, before BMW assembles the vehicle, so perhaps this brace just ties together the two fender modules.

The photo you linked shows a silver coloured strut bar. The Z4 actually has struts under those domes, so it makes sense that someone might want to add one. Those triangulated bars look like the X5 dash panel braces, so they are likely doing the same thing, bracing the dash panel.