Jonsey's Roll Bar Build at GSpeed

[GSpeed]

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

[CarzCarzCarz]

Looks good, keep up the great work GSpeed!

[Jonsey]

Thanks for posting this up. I have been really happy with the process and it is exciting seeing this come to fruition.

Just one point of clarification, the car previously ran a Schroth Rallye 3 Harness properly mounted to the factory belt locations per the manufacturers instructions and not to the seat rails (GSpeed's comment was more of a general PSA). However, this is a concerning problem that others should be aware of to make sure to regularly inspect the seat mounting points. This car has several thousands of track miles and I am not an overly large guy at 210lbs.

[Bramick]

Driving the wheels and harness off your car! Great build. Can't wait to see the finished product.

[Jonsey]

Originally Posted by Bramick

Driving the wheels and harness off your car! Great build. Can't wait to see the finished product.

I see what you did there!

[Devil 86]

Wish I was in Texas. This looks fantastic! Are you guys planning on making a weld in roll bar with landing plates as beefy as those?

[ka-t_240]

Great work, what does something like this normally cost from you guys?

[GSpeed]

Originally Posted by Devil 86

Wish I was in Texas. This looks fantastic! Are you guys planning on making a weld in roll bar with landing plates as beefy as those?

In theory we could, yes. The landing plates were cut off CAD templates and took zero fitting after being tacked together on the bench. Just need to justify the demand.

Originally Posted by ka-t_240

Great work, what does something like this normally cost from you guys?

For the cage (including paint) it comes out a bit over $4k. That could be cheaper since this one is built with extra reinforcement, etc. and has about 35 hours of labor into it at this point.

[GSpeed]

Just to follow up on the failing seat mount, here's a picture of the repaired and reinforced mount:

[GSpeed]

Just picked up the car from paint. I LOVE the color, looks very striking in person, and surprisingly not very visible from the outside.







Need to finish some interior cleanup now that it's painted, then it's time for seats and fire system!

[Insurme1]

Which option is this green bar?

[GSpeed]

Originally Posted by Insurme1

Which option is this green bar?

I'm not sure what options you're referring to. This is a custom build, so we're building it to match what Jonsey wants.

[GSpeed]

In addition to a half-cage, we're also installing seats, fire system, and steering wheel.

As mentioned in other threads, we don't like any of the other seat mounts on the market for this platform, so we're now making our own out of formed 11ga steel:



Jonsey's going with a Sparco Circuit and Evo 2, both great seats:





The fire suppression system is a SPA Technique Fire Sense AFFF system, with five nozzles throughout the car. The bottle itself is mounted in the truck.



The pull-handle for the driver is to the right of the shifter. Far enough away to not be accidentally pulled, but close enough it can be quickly pulled if needed.



The mount is a sturdy steel piece, since if this handle ever has to be pulled, it will be yanked in a HURRY. You can also see the nozzle facing the passenger:



There's a secondary handle behind the passenger seat headrest that can be easily accessed by cornerworkers if needed:



The driver's side nozzle is just underneath the knee pad.



There's two nozzle on the passenger side of the engine bay, one over the fuel rails, and one by the surge tank.



The fifth nozzle is over the driver's side fuel rails.



It's always interesting installing fire systems, since you hope they never have to be used. We've learned over the years how important they are, though. At under $400 they're cheap insurance for the level of safety and protection they provide.

Thanks for reading! Feel free to reach out if there's any questions we can answer.

Jake

[Pat]

I LOVE this build. Jonsey, you're a fortunate guy. I can't wait to see you put this thing to good use.