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Dan, Make sure that whatever type of cage

you go with that the tubes are SEAMLESS

d.o.m. (drawn over mandrel) from what I

understand seamed pipe cannot be certified

for much of anything. I am not 100% sure about this but i dont think that i am

too far off base....

What do you think guys?????????

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Guest Anonymous

Myron is absolutly right about the extruded tubes being required. The Chassis Shop sells tons of tubes both in Chromoly and mild steel. All their tubes over 1" are extruded. I recommend that everybody log onto their website and order their free catalog. It has tons of stuff related to racing and is all applicable to our cars. This discussion has convinced me that I need a roll cage as well. I'm going to make my own though and incorporate it into my spaceframe. 6 points should be enough for my application. Thanks everybody....I think a few lives might be saved by this string.

 

SpencZ

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Myron,

You are right, tubes must be seemless, and I think NHRA and SCCA require thickness to be .120 but I'd double check it. You want to make sure you have the right tubes. No sense installing a bar made out of the wrong matterial. It will save your life though, mine had to be cut out of the car, but was inspected and cleared to be re-used. the car, on the other hand, was cracked in two places in the trans tunnel. That made me a believer in cages for life.

 

Mike

 

------------------

 

"I will not be a spectator in the sport of life!"

mjk

 

[This message has been edited by Mikelly (edited February 15, 2000).]

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As far as I know, NHRA indeed requires 0.120" thick DOM mild steel tubing. Chromoly, if you choose to use that, only has to be something like 0.83". Oddly enough, the industry standard for mild steel is 0.118" ! And that apparently won't pass tech. So what I did was reluctantly follow my hot rodding mentor's advice, and went for the 0.134" tubes - these are the next thickest size. In 1 5/8" diameter, these are kinda beefy. I figure the whole cage will weight at least 100 lbs, maybe 150. That's with diagonally crossed "door bars" (really more to connect the dash-area bars to the B-pillar bars, than to protect the driver in a crash) and a system that ties into all four strut towers.

 

We just bent the big hoop that goes behind the drivers head (the "roll bar", I suppose). We got it to fit just ahead of the roof pillar supporting the hatch hinges, and right against the headliner.

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Guest Locutus

I race stock cars/trucks, and I can also vouch for the effectiveness of a good roll cage. Since I am in a sport that requires alot more cage than most I have a 12 pt cage with 3 driver protection bars, and 2 passenger protection bars. In my very first race, this jerk wanted to initiate me into dirt track stock car/truck racing and slammed into me in a corner at 64 MPH, he broke the steering sector and left my truck with out steering and heading straight for the wall. I hit the wall and rolled end over end, and ended upside down. I walked away from that crash with only bruises from the 5pt harness. On another note, since beauty is of no consequence, I did some pounding and cutting and got my truck back on the track, the cage saved the frame and the driver smile.gif. I must say this it was a he!! of a ride.

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Too Cool! I've done some laps on oval courses, but never in competition. One big thing to worry about with a cage in your car, which does make it a little inconveniant is the casual contact you will certainly have in event of a crash. Michael touched on doing it right and I agree with him in this. A cage that is not properly designed will collapse into the drivers area. You don't want your roll cage to kill you, but beware, the wrong tubing can kill you and the cage should be designed for the vehicle by a compitent engineer.

 

Casual contact you say? Lets just say that roll bar padding is your friend.

 

Mike

 

------------------

 

"I will not be a spectator in the sport of life!"

mjk

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  • 4 years later...
Guest Anonymous
Agreed Pete' date='

Darth gave some nice links to some good mfgr's. Thanks Darth.

Hey Mike or Pete, the side rails on a 8 point, how hard are they to climb over? Im 35 and can't be doing any "Dukes of Hazzard" stunts [img']http://24.4.88.44/ubb/smile.gif[/img]

 

 

------------------

Dan, 78 280Z, 383FI, 700R4 allmost ready!

http://members.home.net/dporter1/

 

 

I'd like to know the answer to this question too.

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After a lot of checking I decided that a half cage was worth a try in my '77, used on the road and at the race circuit. Particularly after having driven a car with a half cage, it felt stiffer than mine and seemed to have more corner grip.

 

Anyway it works, definately a better less creaky car to drive and particularly noticeable is the improved power down out of corners. And the entire structure is behind the driver, no trauma bars to bang your head on and all the interior trim is retained.

 

Heres some pics, fingers crossed

 

http://hybridz.org/nuke/modules.php?op=modload&name=coppermine&file=index&cat=11121

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After taking a good look at the doors on my 240, I decided door bars were not optional. But in keeping with the "original" look, I didn't want any giveaway raceboy roll bars easily visible from the outside. So, The hoop is placed back to be hidden by the "B" pillar (if it had one) formed by the 1/4 rear windows. The hoop is braced by bars running almost the full length (3 inches short) of the back storage compartment, following the body line of the hatch. The front of the hoop is braced by two door bars running forward to the floor board taking out the "dead pedal", which was rewelded to the door bar, and by one horizonal bar designed to sit low enough to allow full vision to the rear through the rear view and hidden from view by the lower hatch. In my case the door bars were carefully placed to keep them straight and clearing all door handles and such. As I sit in the car the door bars pass under the window and attaach to the hoop. The hoop is not set on the "shelf" behind the driver, but is mounted through the storage tray about 6 inches behind the "Shelf". This moves it back far enough to be obsecured by the leading edge of the glass 1/4 panels. The door bars are not hinged. I expect they will stiffen the body a bit, and will provide some resistence to side hits. Total cost, with the work being done by a certified welder using mild steel: $500.00.

 

One sobering observation when hitting JY's: Z's can fold right at the rear door jam. At that point, even with the doors closed the stiffness is in the roof and floor pan. Triangulating steel from the floor boards to a hoop and back down to the rear alongside the tire well will resist that "fold". Just some thoughts.

 

g

 

g

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.................................

 

One sobering observation when hitting JY's: Z's can fold right at the rear door jam. At that point' date=' even with the doors closed the stiffness is in the roof and floor pan. Triangulating steel from the floor boards to a hoop and back down to the rear alongside the tire well will resist that "fold". Just some thoughts.

 

g

 

g[/quote']

 

Yes, there is some scope to run a bar forward and down from part way up the hoop, so that it ends part way along the sill/rocker panel. The mounting point on the sill/rocker panel would have to be carefully reinforced though, othewise there would be nothing of substance to take the load there.

 

And the mounting point part way up the hoop should IMHO also be attached to the body at that point. Load path once again.

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Guest Nebraska_280Z

After reading this thread, 8 point here I come! I am not so worried about the door bars, im 20 and think that climbing in and out of cars is pretty cool. And im not worried about the stealthyness factor, the blower whine is gonna give that away... Thanks everyone.

 

Ned

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Guest BigWhyteDude

Hey zgeezer do you have any pics of your cage? When i finally get a Z (hopfully i will have enough $$ by the end of this summer) i will want to put in some kind of cage. Your sounds like a pritty good set up. Can we see it :)

 

Andrew

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Good info katman.

 

One thing to add about cages that I see a lot of them missing:

 

A proper cage has all (or as many as possible) of the bars ending on a node. I see tons of cages where bars end ~2" away from a major node. This is not at all optimal. You should be able to draw a line down the axis of ever bar going to a node and have them intersect at a point in the center of the node. It is more difficult to fabricate, however, think of it as 'free' stiffness and strength without adding weight.

 

Node.jpg

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The pre-manufactured cages (the links in way up near the beginning of the thread) all looked about the same and the prices are decent but anyone have an idea what shipping to Illinois would cost. I imagine about as much as the cage itself? Also, anyone who has put one of the store bought varieties in what is your experience with fit and seat clearances - are they really custom designed to fit the Z or just generic that has to be significantly modified?

 

Thanks

Cameron

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The only cage kit I'm aware of that will pass both SCCA and NASA inspections is the Autopower weld in Cage. Beware that S&W, Jegs, and others sell a kit that is ONLY NHRA certified, which is a lower level requirement.

 

Autopower had to junk a lot of their cages last year since SCCA and NASA changed their rules for mild steel cages... They now MUST be of DOM material... No more ERW or like materials...

 

I found this out AFTER I got ahold of a four point bar from one of our members here... So, if you are building a car for eventual use on a track, just beware!

 

Mike :D

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There use to ba a cage company back in the early to mid 80's that made what they called either "Hidden Cages" or "Invisiable Cages" or something like that. They where SCCA approved and a bit on the costly side at the time. They did a great job making cages, which I did see one in a old 240Z and there was a easy to remove door access set of bars for those ladies that do not like hoping over the bars. I can't remember much more about the cages but I do remember that the tubes where not round going across the roof line and done the rear pillars. They fit very nice and you had to look for them to see them. I know I dated myself with this one but I would like to find this type of cage again and based upon some of the comment in this thread it seems that some probably would get what they wanted from the same type of cage. Oh by the way the 240Z that I saw was Yellow and in College Station Texas and the cage was not owner made but was bought. It may have been made to his dimensions but its been a long time since I saw it and talked to the person. I'll try to search the internet for the cages and if they are still around I will post it. Hope this helps

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