Metal Fabrication/Replacement:
Next step was to begin on another aspect that is somewhat controversial, an integrated cage/structure. I mentioned the uses of the car earlier in the thread, and, to me, it was important to protect for anything that can be thrown at it while not pigeon holing the car into a track car that can be street driven. I have read many posts, threads, articles, etc… on cages in street cars and I agree they pose a risk for someone sans helmet. I stumbled upon a single thread quite a long ways back that showed an older Nova (I think it was a Nova) with an integrated cage INSIDE the existing structure. Cue the creative juices and some quick eyeballing told me I could get pretty darn close to replicating. I took a lot of photos and sketched up my plan in Microsoft paint, aka my hobbyist AutoCAD. The main objectives were:
- Strengthen the upper structure
- Tie front and rear together more rigidly
- Protect for rollover/accident
- Still allow for 4 passengers on street safely
To do this, I did not plan a sanctioned cage, rather a cage like structure for the car. This system will be considered 6 point inside with ties to the front tubular suspension at the firewall. I am not planning a dash bar or door bars, but will have a removable rear down bar cross brace and harness bar for track use. All other bars are planned to be tucked into the existing structure or have panels built around them to remove a single point of impact in the unlikely event of an incident (things like the Main hoop top section at the roof and Main hoop vertical runs.
As far as material, I am only planning to run this car in SCCA and other comparable rule events. Due to that, I spec’ed the materials from SCCA’s rulebook, and a 1.5 OD .120 wall DOM tube is allowable for 3000+lb cars. My guess is when I’m done I will fall right at that mark, so I wanted to protect for that possibility. This also allowed for a 4.5 center line bend radius, which was preferred in this application.
I spent quite a bit of time planning and discussing with the people I’ve built other cars with to make sure my thoughts weren’t pipe dreams and began fabricating. I started by running a piece of tape under the roof between the inner structure taught to get a measure of the roofs curvature (at least a 10 point representation, and then translated that inner shape to cardboard as a template (at least half the car).