Roll cage gas coupe C

[Boostedballs]

Ok, I'm ready to buy tubing for the roll cage of my Monza. I think I'm going to start out in gas coupe C class since I have 350ci, turbocharged and I'm not doing any chopping or streamlining.
I don't have the new rule book but my old one says I can use 1 5/8" .120 for all of it; however I plan to use 1 3/4 .120 wall mild. I may be changing classes and I want to be sure my roll cage will be enough for future regulation changes as well.

Also, does anyone know of a good place to get the tubing in Northern CA?

Thanks and see you at Speed Week!!!!

[NathanStewart]

I don't have a crystal ball so I can't predict what will happen in the future but it's probably safe to assume that the min tubing requirement won't increase drastically enough that 1.75" od becomes undersized.  So yeah, 1.75" x .120" is totally fine.

I get my stuff from Industrial Metal Supply here in So Cal.  Don't know if they have one up in your neck of the woods or not but great place to deal with.

[Kiwi Paul]

After some research, I ended up buying 1.75x.120 DOM for my car. I managed to get it for $3.50 a foot from Tube Services here in Portland. Had to buy 200 Ft, but split the order with my pal Tony the Engineer who is building a Nash Healey Vintage Race Car for a customer. He has a cage to build as well.

[Boostedballs]

So, should 100 feet do the job on a Monza hatchback? I plan on making a pretty stout cage.

[Kiwi Paul]

Depends how good you are with design, cutting and bending tubes without much waste etc. My T Coupe is smaller inside than your Monza, and by my calculations, that amount of tubing should get you a pretty stout 10 point design, but not alot of additional bars. FHeckro on this Forum runs a Monza--I`d send him a PM and see if he can`t give you some pics and measurements from his car. The main hoop might give you a problem...I think it will be more than 12 feet, not sure. Our lengths were odd at 22 feet each, and were cut in half to get them to the Shop. My main hoop will be just over 11 Feet. Make sure you get at least one long length.....Maybe someone else has some better measurements and advise....

[Peter Jack]

For a stock car I always figured on 200 feet and never had a much over. Then again, in the stock car there is more tubing structure in the front and rear bays than you will probably have.

Pete

[Cajun Kid]

Boost,

On my Studebaker I bought  5 sticks of  1.75 x .120 DOM  and had less than 4 feet left. (I used 96ft of cage tube, not including the 20+ feet of 1" tube for the gussets, FYI new rules prefer tube gussets to be same size as main cage tube)

So you need 100 to 120 feet minimum (my opinion)

Charles

[Boostedballs]

I'm waiting for a quote for 100' from S&K Steel in Sacramento. I won't have any trouble getting 20' sections home, but I guess I'll add another to total 120'.
As far as my bending skills- I haven't done much bending on my home built hydraulic unit that uses Pro Tool dies. I will be measuring twice, bending once!

Gussets- Last I read about the gussets said they should be steel strap welded to the sides of the joint.

[Boostedballs]

Wow- $710.22 for 120' of 1 3/4 x .120 DOM??? seem a bit steep.

[dw230]

A current rulebook may be helpful.

Page 26:
Gussets are required at tube junctions of hoops and shoulder rail. Gussets shall either be made of plate, tubing or fabricated from sheet. Plate gussets  shall be made from mild steel, .125 in. minimum thickness and 4 in. per side, preferably stitch welded on the outside of the tube junction. Tube gussets shall be a minimum of 1 in. O.D., round steel tubing with a minimum of .120 in. nominal wall thickness, it is recommended that tube gussets be of the same O.D. and wall thickness as the main roll cage material. Tube gussets shall be constructed such that the outside edge of the tube gusset be at least 4 in. from the tube junction point. Gussets are required at all shoulder bar attachment points. Grinding of welds is NOT permitted, see Figure 2. Gussets may not be used as aerodynamic aids and shall not exceed 6 in. in length without prior technical review and board approval.

Bold print indicates new for 2012.

DW

[Boostedballs]

Ok, I ordered 120' of 1 3/4 x .120 DOM for $4 a foot!

I'll be at Speed Week trying to peak into cars (especially Monzas) to get some ideas on my cage design. Until then, I have a couple of questions.
First, should I stuff the whole cage inside of the sheet metal or should I run the tubes trough the floor to a subframe under the car? If I go under the car, would it be considered streamlining? I have a subframe there now and it is visible from the side of the car and runs close to the seams under the panels below the doors.
Second, I have dual wastegates that I would like to have exit through the hood near the front, center of the hood through a large vent similar to the Ford GT. http://www.supercarnews.net/video_thumbs/ford-ford-gt-vs-formula-ford-1580626228.jpg  Would this be considered streamlining?

[SteveM]

Please consult with the rules chairman for Gas Coupes.  I don't have my rulebook in front of me right now, so I am prepared to be wrong about this, but....

I don't think that non-stock external subframes, outside the original sheetmetal, are permitted in Gas Coupe.  It is my understanding that under-car subframe connectors are not allowed in GC.  Any cage construction has to be inside the original skin of the car to ensure that all of the factory sheetmetal is attached in it's original position with respect to the other panels.

Steve.

[maguromic]

Put the sub frame connector on the inside (its better for aero anyway), you don't want that thing hanging down in the wind. That's what we are doing on the Firebird GC that I am helping build.  Tony

[maguromic]

Ok, I ordered 120' of 1 3/4 x .120 DOM for $4 a foot!

Where did you find it for $4 a foot?  Tony

[Racerboy]

http://www.cachassisworks.com/Home.html

I would try these guys. They sell tubing and a lot of drag racing chassis parts and they are up north