andris

Without getting too specific, no we don't seam-weld the whole body. There is some strategic welding done to the chassis in areas it needs it, but we don't do the full stitching of every single panel. The cage is well integrated into the chassis and provides a significant increase in torsional stiffness. Without any real data, I'd hazard a guess that seam welding the whole body might only make 1/10th of the cage's contribution to torsional stiffness, but this is really just a guess. There are likely very few who have gone as far as computer modeling the stiffness increase provided by seam-welding. This would be the realm of a 100% factory effort with an unlimited budget. For the most part, i think there are just the people who do it because they think it helps, and those who don't do it. I know that rally guys have good success with seam welding to prevent long-term stress fractures in the unibody, but I think this is more of a chassis longevity thing vs. stiffness. One other fairly important reason for not doing it is crash repair. It is a lot harder to replace sections of the unibody when you have to grind off strips of weld instead of just drilling out the spotwelds. The cars do get damaged somewhat regularly, and have to go to the bodyshop for new paint/parts. That is not to say that we or others wouldn't still do it if we had real concrete numbers on the benefit it provides If there is an advantage it is usually taken. I'm sure there are plenty of teams in our series who do it.

andris