Good suggestion SCG. If I get a chance, I may try plugging it back into ANSYS and seeing what it says just for kicks. I wish I could lose the driver and engine and some other stuff so I could get a real space frame.
I'd be curious to see how much that tube will really do since the sides of the frame don't appears to be as stiff as the transmission tunnel under torsional loading. Even if that brace is stiffer, if the stuff its attached to isn't it probably won't carry the torsional load like we'd hope.
The safety point is valid. The one thing that makes that tube missing less scary is the support from the rear structure. The 'box' that the rear supsension mounts to should be a pretty good structure for the hoop braces to mount to. The pic shows how this all ties in.
Right now elbow room is the driving factor against adding more stuff there but I'll find out for sure once I get a chassis together with the steering and everything else. If it fits, I'll probably toss it in.
I've seen a few cars with the side bars like I've pictured below in the pic with the full cage; if time and space permit, I may go with these since they'll also double as side impact protection.
Puk, that block is just 6061 aluminum. The stud on the balljoint is tapered (1.5" taper per foot) so all I had to do was drill a hole and ream it until the 'joint' on the balljoint was in the correct position for the suspension geometry. The castle nut can sit inside of the upright then.
The balljoint is made by Afco and its part number 20034. The threaded housing is also from Afco and its part number 20043.