Some of you guys might remeber me talking about building my roll cage. Well here is some pictures. Its not 100% done but most of the hard work is. Im still need to weld in the diagonal bars from the main hoop to the floor. I also need to x-brace the doors and extend the cage into the engine bay, but as you can see its comming along nicely. Its a custom 1 off piece i built. I dont have any interior, but im thinking i left enough clearence to install all the plastics and the headliner. All the points to the floor and the a-pillar to halo, and halo to main hoop are mig welded, all the others are tig. Anyway here are the pics

 

Looks like its coming along nicely Killer!

 

I don't think there's a chance of getting the stock dash back in there! I like how the "main hoop" is supported by the rear bars and the X pieces on the shock towers. Your gonna need some slicks for that car.

 

:haha: yeah no chance in getting the stock dash in. Im gonna make a aluminum dash. I plan on running 28x10.5 inch slicks. unless i can fit something bigger under there. good thing i have the best rear money cam buy

 

Nice setup b

Why can't you fit stock dashboard? Can't you adjust it somehow to fit?

 

You would have to cut out a section along the backside to fit over that tube. Much easier just to make a flat sheet of aluminum into a dash AL looks better too IMO

 

Depending on hp your gonna run and might run in the future, now would be the time to at least mini tube it since the car is gutted. I plan to do this in the near future and still use the Moser rear, I'll just be ordereing some way offset rims so I can continue to use the Moser rear until 1 day I tub it big time.

Cage looks great but with that set-up you r gonna have some power so try to think ahead now by maybe cutting out the X bars and moving them inboard a lil bit to allow for more tire clearance.

Just a thought for the future is all that save ya alot of BS later

 

Very good point Mini-tub now will save a whole lotta hassle in the long run. Once I get a Firebird to work on, mini-tub will come before cage. May as well do things once and not re-do them later.

 

that always makes me wonder... what do the braces comming down all the way at the back of the car, WAY behind all of the suspension really buy you besides extra weight?

 

There isnt anything back there to tie them into...

 

If he were to mini tub or tub it would help with the overall shell integrity front to back to tie the entire car into one, but as it sits, I would say it's more of a safety item than anything else.

You hope nothing ever happens at a track, but I personally seen a car that went into the wall at an estimated 120mph-backwards after his steering shaft pulled out of the steering box.

 

That's some hardcore stuff man

 

the way i see it is the x-brace is for tortional strength, and the straightbars are for strength if the car rolls over (which i hope it never does )

 

im just gonna stick some 10.5's under there, maby a little hammer work but i dont plan on mini tubing it. hopefully with some sticky rubber ill be able to out the power to the grond

 

Ok i guess i see that logic.

 

I'd buy that if they were tied into a location like where the X bars are, but way back there they will not give much strength to any part of the car, they are too “flat” to hold the main hoop upright and they are not tied into anything all that solid.

You could make a small argument that it protects the gas tank in a rear impact, but real world I don’t think it affords a significant increase over what the axle/tires give with the rest of the bar tied into the suspension pick up points.

I personally like the X for torsional strength, but in the interest of weight, if I was doing that I’d probably bring the normal bars down to were you brought the X down, and then put one diagonal bar in that would give you most of the torsional strength you’re getting from the X plus more overall rigidity with the main down bars tied into something structural.

 

IHI, actually I just took a closer look at your example and low an behold, it looks like it was done like I described, with the X tied in in the same location as the down bars… that is much stronger...

 

Yes, they were tied into the back connection, but keep in mind that is a tube chasis car, and the blueprints we have for my in laws chasis car shows the same thing tieing the rear X brace into mounting point for rear downbars into the chasis frame rails which is done for obvious reason since the chasis/cage IS the car.

Is this case with the 3rd gen, the overall design is good, in fact I've seen 4 outlaw 3rd gens at the tracks this year with similar set-ups, SIMILAR, but each case was different duw to car/design/owner/fabricator/etc...I agree since he has NO plans on tubbing/mini tubbing rear down bars "should" have been welded where his X bars are near the shock mounts and then the X bars tieing into the intersecting points on halo and plate where down bars meet the car.

It is what it is, he's not autcrossing so not much twisting taking place in stock shock area, and there's guys running 1.3? 60's with similar set-ups (stock suspended) and no problems....ideally maybe not the best design from an engineering standpoint, but overall it will not affect performance in the least....but if he does get rear ended it's gonna be in better shape than if the bars were'nt there since it'sll transfer all the energy throughout the cage, without those bars it'd just be a rear crumple zone.

 

Sorry I don't have a picture but my rear bars are just the 2 bars x-ed. I have them mounted above the rear "frame rails" on top of the area that's above where the gastank should be. Best description I can give I thought about going right to the rear but at the time, I also had other fabrication work that prevented that from easily being done. I used to have a rear firewall with the fuel cell at the rear and stuff.

The only comments I can say about the above pictures is that I see the A-piller bars are bent where they attach to the halo bar. Some 1" tubing in stratigic locations around the cage doesn't hurt to help triangulate the cage some more. Small sections in the corners to act like gussets. I haven't used any 1" tubing yet but do have small gussets in most of the corners for extra strength especially where there's a 90* corner.

 

Yes, I totally agree… that would be much stronger if the bends around the halo were not there, and some 1” bracing would help significantly (and looks cool also).

Now back to hypercritical mode… gussets are nice in square corners, but the fact is that where you show them in your picture, on either side of one leg of a triangulated X brace, you probably added about as much strength as you added weight, if that (that is to say, not much) the X will prevent any real side loads making the braces/gussets unnecessary.

Secondly, gussets are stronger if welded to the sides of the tube then to the centerline (they act as kinda a can opener if welded to the centerline and significant side loading is applied)

IHI, we are totally on the same page, I think. The only issue I would have is that you mention “crumple zone” like it would be a bad thing, where I would argue that a bit of a crumple zone before it contacts the solid structure of the cage is a bonus safety wise, it would have the ability to absorb much of the force of an impact before transferring the force to the solid structure surrounding the driver.

 

I actually do plan on adding braces to where the a-pillar bars and the main hoop to halo are welded ie where the bends are. just like i said im am not done yet, i just have all the hard **** out of the way