Recently, we were contacted by member @
Jonsey about building a custom 4-point roll bar for his FR-S, and of course were were more than happy to oblige.
We based the design off an 8-point cage, since we wanted to have the option open to upgrade to a full cage later. Therefore all tubing sizes and landing plate dimensions are done per NASA & SCCA roll cage spec. At his request, we added some extra reinforcement like double diagonals on the rear roll hoop support, and some horizontal bars between the main hoop and hoop support landing plates.
Everything was modeled in CAD before we got started, to make sure everyone was on the same page with the design and predict any potential snags or challenges.
This also gave us the opportunity to trace and cut out landing plate templates, meaning they dropped in perfectly saving quite a bit of time. Here are some pictures of the current state of the build. We're waiting on side mounts for the seats to show up so we can properly position the harness bar, then we'll weld everything up and send it to paint.
We also found this somewhat concerning damage to the rear outboard driver's seat mount:
Over the years, our guys have installed probably hundreds of race seats, and no one has seen this sort of failure before. We'll be patching it up and reinforcing it, but this is a great indication of why racecars have to have harnesses mounted to the chassis, not the seat mounts.
(Edit for clarity: This car did not have harnesses mounted to the seat.)
We'll also be doing seats and fire system installation in the car while it's in our shop, so we'll update this thread as things progress. Thanks for reading!
Jake