Paulyy

I welcome people to post photos of their Roll cages and to what specification built to (FIA, CAMS ect) and if it's registered/approved or not. Reason being is that I've seen some silly designs that i know wouldn't be approved.

I've been searching quite a lot, just to get ideas on how specific sections are made but photos are missing on a lot of threads and google is sort of helpful.

Discussion is welcome and please it on topic.

Thanks.

Humboldtgrin

Noahs944

Finally finished today. Built this under FIA specs, with the exception of using a "Halo" hoop overhead.

Paulyy

Why not! just put details on manufacture and standards.

looking good! Are you allowed to do the hoop? i noticed it on your thread. Are you allowed to get yours registered with that?
Should post more photos. Thanks!

951and944S

Whoa...., having previously stated many times here, the racing content is way underrepresented here.....so when I see a topic like this, I get exited about it.

This is right up my alley, all things race car construction.

Paully, I think you'd be better off asking specific questions....., but

The first real step is defining realistic target weight of your car, as finished without the driver as most sanctioning bodies lay out material parameters based on that.
For us, with these particular cars, it's either above or below 2500#.

Let's start there and I'd be happy to walk with you the whole way through this.
I have cage design software that I can replicate any tube bend that you can visualize and give me specs for that I can reproduce in the software and post it here to view.

T

MAGK944

Noahs944

P,
It'll be good around here because the Halo is an acceptable method & one of the 3 listed in the manual which I've referenced.
All proper cage builds have this in common: very snug fit next to body. This becomes very difficult to fully weld around the tube joints. There are some solutions to overcome this problem, such as square tube blocks to insert under the tubes once the cage is welded, or holes in the floor which are later plated over. I built my cage with windshield "in". Some people cut the roof off. This was a lesson in difficulty and I'm so glad it's done!

Paulyy

You are right about that!
i've actually started, I've made the main hoop, Lateral half roll bars (from the main hoop, around the door to the dash to the floor) so all the main bends are done.
I've got the Back Stays done (rear main hoop supports) and braced. The main hoop has the X in it.

I now wish i had asked earlier. I had to remake the Lateral half roll bars as i wasn't happy with the first set i made. (it was hard to find a photo on how high people make these and how close to the wind screen. and just general placement of bars.

Tomorrow i plan on doing the roof and get started on the side intrusion bars.

I am using 1.75" x 0.095" tubes for my main roll bar and 1.5” x 0.095” for the rest of the bars.

The car (924) is getting built for club sprint class in time attack. Which needs to be street registered and aero with in limits. Weight needs to be at least 1026 kgs / 2262 lbs. (curb weight - 5%)
I need to keep some of the interior like dash and door cards.
Im not going to over do the cage, just to CAMS specifications. So i wont need to do an X bar in the rear and roof.

Noahs944

Other common themes of proper cages include:
-gussets. Always used to re-inforce tubes or joints, but there are at least 3 different accepted methods (1mm thick plate "taco wrap" over tubes as in FIA), 3/8" thick plate welded to side of tubes, or round tube). But you need to consult the regs.

Noahs944

P,
WOW! You're way ahead here. 944Sand 951 is definitely "the man" and he (and others) are far more knowledgeable than I. But if you don't mind I will still engage in the community conversation. Are you installing a dash "knee" bar or the tubes that go forwards from the pillars to firewall?

951and944S

Well then, consider going further forward with the door opening bars than the dash will allow.
I am a fan of keeping a portion of the factory dash too as it keeps the cars appearance as a recognizable 924/944.
I cut the dash left and right most outer A/C vents and go all the way forward that the front cowl will allow and then I connect the dash to the roll cage with a short 1" box tube and dash mount flange.

I don't have pics to load here at work but I think I had posted these in one of Noah's threads if he could find and link.

Software has selections for Inside, center and outside DIMS, so on bars where tight clearance is target (keep consistent gap to door roof line), I make accurate measurements of the space and use outside dimensions in the software. The software allows you to "verify" with a measuring tool so I can open a 3D representation of my bar and rewrite my bends in .1 degree until I achieve as close a tolerance as I chose when compared to the known space measurement of the car.

T

Paulyy

Yes i'll be making gussets with 1mm plate and dimple died.
FYI - CAMS is our National Sporting Authority and delegated this responsibility by the Federation Internationale de’l Automobile (FIA)

He is definitely "the man" he's helped with all my questions so far. Anyone's welcome to engage!
At this moment i will not be installing the "knee" bar. It's not needed so i probably wont do it, Just like the X bar on the back stays and roof.
If i do put in a knee bar it'll be tucked behind the dash as far back as possible.

Paulyy

I'll snap some pics tomorrow when im at my shop.
I've made mine go as far back as possible so i cut the rear of the dash and the front wont be touched. (it follows the door line)
I have been though Noahs thread a few times.

The software would have been helpful! thanks though.
We just use good ol' maths to get our bends. the main hoop isn't as close to the sides as we would have liked but it's not to bad about 20mm gap From what i can remember. It's as close to the roof as possible considering everything on the sides getting in the way.

Noahs944

P,
I understand the benefit of a simple cage to just meet standards. It saves frustration and time. Also less chance of starting your car on fire. However, in my personal non-scientific study of types of damages incurred, I strongly think a dash bar & firewall extension are in order. I think you'll find they are added to many "minimum standards" in racing circles (as we witnessed locally). Safety standards ALWAYS increase & never decrease. Having said that, here is what I did & can confirm these were the worst bars to weld on the entire vehicle. Drove me insane! Also started the car on fire like 40 times (near the late model fuel lines no less!). But ONE & DONE.

951and944S

20mm side clearance is good. It's just an exercise of demonstration that you can do it to be any closer than that, it won't serve any further safety purpose.
In a NASCAR or such, being tighter or attaching with sheet ties to a & b pillar allow a crashed car to keep it's panel profile to continue on racing without too much aero handicap, etc.
Up until last year's rule change that allows a driver to continue racing after a body to body contact, we'd have to report to the black flag station so in the event that you were re-released to proceed racing, for all intents and purposes, your race was over anyway.....so for us, minimizing body panel deformation is a non starter.

The roof, for me is a different story, minimum space between outside dimension of the bars and the roof increases driver room in the even of a roll over, however rare an event that might be.

It's key to keep in mind that the unexpected is always a possibility and the cage is a safety item to protect you from injury as it's foremost important duty.

When weighing a decision between weight savings and strength, always err on the side of strength.

T