116 roll cage

[Storm_X]

Does anyone know of any places that sell roll cages in a kit for a 116 Giulietta ?

[festy]

Have you tried Bond Roll Bars?
I remember they had a number of alfa designs on file when I bought mine a while back...

[BradGTV]

Half cage or 6 point? Walker chassis does them for gtv and I think alfettas aswell if there the same as giulietta, not sure if I'll buy one or make myself for the Monaro , he wants $1100 for the main hoop and side bars bent up. U gotta cut the rest to length and notch the tubes.

[Storm_X]

Just seeing what's out there pre bent. So far I seem you can get ones from the UK for $1500 including delivery (last time I check was last year) an u think that was a sparco brand cage. There is a guy who runs two giuliettas in the classic Adelaide and he has made his own and quoted me $1400 for everything CAMS approved. Or I know a guy from school and his dad owns a local mechanic / exhaust shop that does them for around $600 for a half or $900+ for a full (unsure if cams approved)

[Duk]

Or I know a guy from school and his dad owns a local mechanic / exhaust shop that does them for around $600 for a half or $900+ for a full (unsure if cams approved)

What ever you buy, make absolutely sure that they are making the cage from cold drawn seamless pipe! Also called DOM (Drawn Over Mandrel) by the Yanks. Cold drawn seamless is 'just' mild steel, anyone who says otherwise is full of it.

V8 Supercars use 4130 Chromoly pipe, but the whole chassis (the cage actually becomes the cars chassis) is then stress relieved after it's fully welded. Unless someone can stress relieve the cage after welding, Chromoly probably isn't the best choice, even if it does have much higher strength to weight ratios than regular mild steels

Any bends must maintain as much of the original pipe diameter as possible (I'm sure that there would be a maximum bend crush percentage figure available from CAMS). So only mandrel bending is applicable.

There has been a recent trend in making 6+ point roll cages that contour around the dashboard. You see plenty of these in Japanese cars. If someone tries to sell you a cage that has this, take your money elsewhere!

A good cage will add substantially to the chassis strength. Adding tag points to the A and B pillars will help increase torsional rigidity. Be aware of what the cage is actually attaching too, especially on the floor and sill pane/box section area. The chain is only as strong as its weakest link. If the cage is attached to thin sheet metal, when push comes too shove, the sheet metal will deform well before the cage will and that's a bad thing!

[BradGTV]

material requirments varys from class to class but generally only the main hoop must CDS (cold drawn seamless). CDW (cold drawn welded) can be used in all other parts. 

bending does NOT need to mandrel. bends obviously have to be cold and the radius has to be 3 times (normal industry requirement, not sure on cams) the tube  OD. when bends are ovalised there is ratio between minor and major diameter that needs to be checked.

id be a bit weary with a 'mechanic' making a rollcage, sure they might have the bending facilities but your putting ur weldbeing into someone elses hands. i personally wouldnt let someone else weld my cage unless they atleast SP (structual perpose) qualified. joint preperation is one of the most important factors in welding,  to notch the tubes to suit to have a perfect fit up (allowing complete fusion of both surfaces) requires a fair bit of skill and time to do and would surley not be that great (meanning insufficiant weld strenght) for the prices mentioned. there would have to be short cuts taken somewhere. 

just some thoughts, i could go on and on about fabricating a cage, but thats not what chris wanted to know. be carfull of the quality of what your buying, after all it could be a matter of life and death.

[festy]

material requirments varys from class to class but generally only the main hoop must CDS (cold drawn seamless). CDW (cold drawn welded) can be used in all other parts. 

According to the CAMS manual General Requirements Schedule J, CDW is fine for main hoops (http://www.camsmanual.com.au/pdf/10_gen_req/GQ11_Schedule_J_2012-2.pdf table 8.2 and 8.3).

[Storm_X]

I wouldn't get the roll cage done through the exhaust shop. It's either get back in contact with the guy that has done a hand full of alfas for the classic rally. Or try to find the ones from the UK. Just trying to find the pipes pre bent so I can do a bolt in cage ,welding is no problem at all, my old man is a qualified welder has been for over 20 years.

[Doug Gould]

A mate in Thailand put one of the UK kit cages in a Fiesta and it was quite good.

Most tube sold as Cold Drawn Seamless is not actually that, rather Cold drawn welded tube that undergoes an additional drawing process that eliminates the seam. But that said, it works pretty well. Most roll cage tube in Australia is sold as 350 MPa tube but typically tests in the low 400 MPa range. I'd prefer to see higher tensile steel than this. You might as well make it out of PVC pipe as use seamed tube. Cages fail at the bends and both seams and necked bends create weak points that create yield points.

I have actually tested a roll cage that was sold by a well known company which was literally made out of exhaust tube. It came from Indonesia, but it does happen.

For motorsport cages (which are basically custom built),  the critical things are fit (small gaps to the body - bodies can vary between cars by 20 mm or more) paint finish (if you want colour matching), weld quality and mounting points. In order to work, a cage must stay upright under impact and the quality of the footplates and the mounting of them has a large bearing on this.

I think CAMS has made some changes recently - I'm not sure. But make sure you get a sign off for CAMS approval. FEA is commonly used for CAMS approval. The trouble is that the assumptions used for joint stiffness and mounting stiffness are not usually disclosed and they are the parameters that determine the result. I haven't found much correlation between FEA results and real world tests. I think David Brown at Brown Davis may be the only ROPS manufacturer who does physical testing. I know of another who is getting ready and I know of another which has done some in the past, but at the moment, I suspect Brown Davis are the only ones.

Compared with the industrial ROPS ,which I get involved with,  motorsport ROPS have the advantage of shorter tube lengths and greater cross bracing. The more the merrier I'd say, although you need some energy absorption, which requires deformation. It gets very complex.