Cage

[Greybeard]

I'm putting this in General discussion as the answers are more subjective than black and white.
My Vega has a welded in, square tube, subframe. Plus, the previous owner installed an 8 point cage with halo bars, but no door bars. Obviously it's for looks and not to meet some racing body's rule book. I love how solid this sucker feels. The chassis feels absolutely solid. No cowl shake, or twist. The "however" to this story is the halo bars. The rest of the cage isn't a problem. The halo bar runs right beside my head just above my ear, and less than two inches away. If I don't have a helmet on and get into some kind of trouble, I could be badly hurt, so I'm playing Russian roulette driving on the street. I first thought about door bar without the halo bars to keep whatever stiffness the cage adds to the chassis, but stock seat and door panels don't leave room. Besides, I'm 6'3" tall and 72 years old and don't think I want to be screwing myself into another cockpit.
So, after that "old fart" long winded lead in, do you think I'll be satisfied with the stiffness afforded by the subframe connection if I remove the cage?

[Choppachris]

I wouldn't take a chance on your head, and cut that "halo" out if you are using it for street driving. You could run a door bar from the main hoop that's behind the seats down to the forward rocker and still gain a lot of chassis stiffening. I am not an expert on this matter however, and maybe someone with more experience will chime in.

[bbcowboy]

I had the same issue about the cage... I also will be driving my car on the street.. my cage was modified.. I still have the main loop behind the seat...there has been discussions that my cage wont pass certain rule packages.... but for mine I am good for what I will be using my car for

[spencerforhire]

If you're not worried about passing tech at the track because your Vega is now a street car, but you like the "solid" feeling of the full cage, maybe consider re creating the halo bar out of smaller tubing and have it tucked up tighter to the roof. That and some padding might let you keep it stiff without whacking your noggin.

[Monza Harry]

That and some padding might let you keep it stiff without whacking your noggin.

We wouldn't want to dent the tubing . Sorry I can't help myself sometimes! Like Spencer says you could reduce tube size and move it up and out and if not stiff enough you could double the tube. Your bender guy should be able to make a nesting pair for each side. With a Finite Element Analysis [FEA] from an engineer it may still pass tech. That would be an ENORMOUS fight though I'm sure. Harry

[Greybeard]

back in the '60s', I stuffed a BB into a '64 Chevy ll and went racing. We built the equivalent of today's ladder bars with adjustment available to preload the right rear. During the year I found myself revisiting the adjustment on a regular basis, and having to make modifications for additional adjustment. There were no mods to increase chassis stiffness, and we hadn't "stitched" the seams. With 10.50 x 31 M&Hs, running 11.10-20s @ 120mph or so, I twisted the car up pretty bad. With the front bumper level, the rear bumper was 3" high on right.
I'm going to put in some track time next year with the Vega. I won't be using that much tire, 8.5x26x15 m@h, and no 6500rpm dumps, but I don't want the repeat of the Nova. Will a car with just the subframe work hold up under a full season of flogging, or do I need this cage? I'm only familiar with the effect of stiffening up the '60s cars, and just the subframe work did wonders for them. A cage was just fuzzy dice and dingle balls.

[spencerforhire]

The H-body floor pan is pretty flexible, so anything like frame connectors or a back half will make a big ddifference. But the cage probably will do more to stiffen up and tie everything together.

[myvega]

The halo bar doesn't do a thing to stiffen the car. You need to install the door bars, and create a triangle with the main hoop and the rear bar. (think roof truss)
I've gone 9.90 with no frame ties, and I've been doing it for years.

[Greybeard]

I want to thank everyone for their responses to my question. I've wanted the halo bar out of there since I got the car. Had there been room with the stock interior to install door bars, I would have done that and removed the offending halo. There is not one triangle to be seen in the cage. As in Jim's (myvega) analogy to trusses, my cage was relying on the stiffness of the material without thought to engineering.
Yesterday I took some time to see if there was a build or pics of Jim's build. Although I didn't find a build thread, I found an answer. BTW Jim, that was an awesome season you had with your Vega. There was a post mentioning "structural foam". I think that might just be my answer to having a stock interior and gaining back whatever stiffness a non engineered cage may have contributed to my car. I won't be going quick enough for NHRA to require a cage if I read the rules right.
Again, thanks everybody for posting your thoughts.

Mike

[spencerforhire]

Triangles? I got lots of 'em-
http://i331.photobucket.com/albums/l454 ... 011002.jpg