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....One way to get away from some of the need for this device is to stitch welld the seems of the unitbody every 12 inches or so. Also, tieing in the two subframes of the car together will help with torional chassis flex. I want to take my cage and run it thru the firewall to the strut towers, and back all the way to where the rear bumper struts bolted in. However, that will have to wait.

 

One thing that Pete and Perry made me think of is the fact of too much rigidity and the torque load on the trans case. I was looking at tieing the two units together, but my design won't work simply because of the flex needed. Now, a track bar with heim joints (Sort of like a pan hard bar) might be the ticket, not sure though how much I need this with the rest of the fortification I have done. I already have the steel front diff mount in place. Also, I have driven my car a little bit and noticed no adverse issues with

the drive train. Lets kick around some more ideas on this topic.....

 

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Guest Anonymous

...guess we can continue this post here! the thought of a dedicated roll bar kind of makes me cringe. I know they are very functional and probably a priority with HI PO enignes, but frankly they look like @#$%. If in a racing car, they look at home becuase all the interior trim is removed and nothing pretty is left to cause extra weight. My car won't be a dedicated race car and will most likely never see a real track in its lifetime. I really want the stock appearance to be left in my car, but I won't sacrifice safety of myself and my passenger to do so. so the question is...can a rolbar be incorporated in a stealthy manner that allows the interior plastic to be used, and keeps suspicions low when my mom decides that she wants a ride??

 

spencZ

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Well one reason I have a cage in my street legal racer, is because of a bad crash I suffered in 1996. The Z I was driving was totalled when I was hit by another car while on the way to see as prospective sponsor. That roll cage saved my life. Regardless of the "LOOKS" a cage may have, or the lack of space, a V8 Zcar puts out enough torque to warrant the use of one. Any 2700# car with 350+ HP and 400FT# TORQUE should have one, and not a whimpy 4 point bar... a full cage. Thats my $.02

 

Mike Kelly

 

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

mjk

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Speaking of rollcages, I can't find a pre

made one for the Z! Autopower has kind of

a 6 point with weld-ons to make it an

8 point, but it's not nhra approved! I guess

I have to go with a custom made one...

 

Spencz, the autopower one looks like it will

go into a z without tearing up the interior

too much, it doesnt have the front pillar

bars but it does have the 2 diagonal door bars.

Owen

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Guest Anonymous

Try S&W Race Cars at www.swracecars.com you will have to call for availability..but they have one, Art Morrison at www.artmorrison.com You will have to call them to get the info but they have a 6point 8point and a 10 point, Also call Competition Engineering they have a full line of cages for the Z...not sure of the number but the webpage is www.competitionengineering.com.. There..that should keep you going for a while..all are great...take your pick. Hope this was of help.

 

Later

Darth Vader

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I'd be inclined to comment that a car with enough power and torque to appreciably cause structural problems with its unibody is already enough of a "race car" that we can no longer apply pure street-only concepts to it - regardless of whether you actually race it. Conversely, a car that is only driven in "street-type" situations probably would not benefit from a huge amount of torque, with the possible exception of rare and brief smile-inducing bursts that in themselves do not justify going to the effort of installing extensive structural mods.

 

Probably your best bet would be simple strut tower braces. These can be home made with a drill, hammer, vice, and saw. Beyond that, consider subframe connectors, especially if you have a 240Z.

 

I decided from the very start that I wanted a maximum effort drag car, and that drove my decisions on structural reinforcements as well. But perhaps people are too concerned with the example of those individuals who really do have full-effort race cars, and who really do need roll cages etc. Most V8 Z conversions would probably be fine with no cage and no braces of any kind. If I were doing the conversion alone and on a tight budget, I would not worry about structural mods, because the car that I could realisticly build would not need them.

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At the risk of ruffling some feathers, I'd have to say that a bolt-in pre-fab cage is not a good idea. That's especially true for Z's since NO MAINSTREAM HOT-ROD MANUFACTURER makes an NHRA-approved "kit" for the Z. If you call Morrison, S&W, Magnum Force, Steve Alston, whatever, they will sell you a generic package of tubes designed for a Vega or Pinto. They don't fit well, and they are plagued with unbraced bends in the tubes (prone to buckling).

A real cage is A LOT of work. You end up stripping out the entire interior, the carpets, plastic body panels, everything. You clamp the unibody to a rigid chassis jig, so that the thermal stresses from welding don't cause displacements in the metal. Then you have to worry about where to anchor the tube ends. Sheetmetal? Forget it. You need reinforcing sub-structure underneath the cage. For maximum benefit, you need to weld a network of gussets to secure the cage to the room, B-pillars, etc. And you will end up with diagonal members barring the door openings and criss-crossing the car.

 

IMHO, if this is not what you want, don't build a cage. (My appologies if I'm starting to sound like Mark Sayer smile.gif )A hoop behind the driver's head might save your life if a tractor trailer rolls over the rear hatch, but it won't do much for the structural integrity of the car - especially for torsional stiffness.

 

BUT - I've seen 11-second V8 Z's run at national drag racing events with simple roll bars and subframe connectors. We're not building 1200 hp pro mod dragsters here (and frankly, I think that these pro-mod dragsters are not very well braced either). If this is a budget V8 conversion, if you spent $500 of a Z shell and most of your money is going into the engine and drivetrain anyway, it makes more sense in the long term to just let that unibody twist and then discard it and to buy a new one. Building a cage becomes like paying more for insurance premiums than the cost of what you're trying to insure.

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Guest Anonymous

Michael...

I have spoken with two people that have a competition engineering cages that were designed just for the first gen Z. In both accounts the cage fit great and it came with gussets to give the cage strenght. Subframe connectors and a cage will protect the body from flexing and destroying the body..and if you are building a V8 z car to run 11.99 or faster you MUST have atleast a 6 point roll bar. The bars donot have to crisscross the back and as far as the side diagonal bars concerned you can have swingouts put in so that you can remove them when driving on the street and put them in place when racing at the strip. The cages from the companies I listed above are not bolt in cages (bolt in's are not nhra approved) they weld it. Now..you speak of a rigid chassis jig...true if you are building a tube frame car or if you are tubbing out the rear and adding a 4-link setup, but the welding heat will not distort the chassis as you say...not like not putting one it and letting the body twist on you. I'm sorry if I sound like I am on a soapbox but...If I put time and money into my Z..ridding it of rust, dents,dings, and buying new seals for it and a nice new paint job...then I sure dont want to watch it get twisted to #e!! just to pull every thing out and start over on a different car. What's the point! If you just wanted to build a V8 Z just to let it twist and then discard it and get another..well I have a friend who has a large metal crusher...it would be more fun to watch the car get turned into a paperweight. I know its your opinion and everyone is intitled to their own..and this is just mine..but If I put much value and work into my Z or any car for that matter and you plan or racing it...and dont want to have to build another one in a few years (and plan or running 11.99 or faster at a NHRA track) then a cage is a wise investment. You can also check around at local speed shops for locals that build custom cages...most charge about $100 dollars a point..so a 6 point cage would run about $600 dollars. Anyway..I have said enough and I hope this is not taken the wrong way..I am just voicing my opinion.

 

Darth Vader

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Guest Anonymous

I here ya 'Darth...I certainly wouldn't bust my A$$ just to have it all twisted to @!%#. I also think that saying a full roll cage is the only way to go is like saying you might as well live in a cardboard box if you can't afford Malibu. I am convinced by this thread that I need to add something into my car that resembles a rollcage...just stealthier than most

 

SpencZ.

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Thanks for the links Darth, S&W specifically had a kit for the 240Z! Shipping is high

dollar but I guess I can't complain.

I noticed that the Art Morrison 10 point

cages looked different than the S&W cages.

They had bars that look like they would extend into the engine bay, that's not for

me.

As for Competition Engineering, I had asked

them before if they had anything I could use for the Z and they simply said "no". Hmph!

Owen

 

 

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http://www.homestead.com/s30z/index.html

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Guest Anonymous

Owen,

I had to ask twice to get the right answer from Comp.Eng. The kit that they have is for a 240 but it will work just fine in a 240,260,280... Your are right about the shipping though..it will be high. Look around local and compare cost and ask to see some of their work...couldn't hurt. Hope I was of some help guys.

 

Later

Darth Vader

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Well here is what I did:

 

I originally bought a 4 point autopower bar since I was autocrossing. I then took the car to a shop in the Manassas Va area where and engineer added the front hoop around the door and windshield frames and built in door bars. The reason the system was bolt in was because SCCA rules dictated it at the time. I used 1/4 inch backing plates and Grade 8 bolts. The car did not twist and the bolts did not work loose.

 

Now, questions have come up about welding in cages Vs. bolt in cages... Absolutely without a doubt, welding a cage into the car is much better than bolting it in. However, A bolt in cage is a better alternative than none at all. And Michale, as for its uses in day in, day out traffic, All I can say is that the state trooper, the insurance company, and everyone else who saw my car Knew that the cage saved me from personal injury. The rear bumper strut of the car was touching the strut tower, and the hood was hitting the windshield and roof. The motor was shoved into the firewall. All that damage occured when a 6500# truck hit me when he was doing in excess of 40mph and I was at a dead stop. He sandwhiched me between himself and a Ford Taurus Sedan. I walked away with a small bump on the forehead.

 

If you have a cage custom made for the car, and don't use door bars, you will have a very unobtrusive piece of safety equipment. I am a big advocate of their use, especially in the Z, and especially with anything over 200HP. Remember, the chassis wasn't designed for that kinda torque and HP that mild modified V8s put out. And if you paint a Z, spend a bunch of money on getting the body rust free and suspension and brake upgrades, I don't think you would want to twist it up and Use it like a plastic cup, tossing it away when its life is spent.

 

My $.02

 

 

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

mjk

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Guest tom sixbey

ok guys, about those weld in cages, does anyone know for sure if they will not require the removal of the interior plastic panels? - if i must remove my interior i will, but i'd prefer to kep it if possible. - ive asked people this b4, but i got many different answers... -thanks guys!

 

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Tom 6B (73NIC)

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All you should have to do is weld in the footers and upper rear side hoop to the rear 4point hoop. Shouldn't be a real problem, as any good welding shop will have leather covers for most this. Remove the seats and carpeting and you should be good to go...

 

Mike

 

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

mjk

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Mike Kelly,

You said,"If you have a cage custom made for the car, and don't use door bars, you will have a very unobtrusive piece of safety equipment. I am a big advocate of their use, especially in the Z, ..."

 

When you say big advocate of their use, you mean the cages and not the door bars right?

Although I assume you recommend doorbars also.

 

Darth, how much was your Competition Engineering cage? Any part numbers?

Owen

 

 

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http://www.homestead.com/s30z/index.html

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I recommend using the cage w/ doorbars if you can live with getting in and out over the bar. At the time, I used my Z as my primary car and the girl I was living with gave me tons of grief over hoping over the door bar to get in the car. So, I pulled them out. But definitley using them (Door Bars)during competition is a must.

 

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

mjk

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Ditto to that, Dan. I to was on the fence,

but now I think I want at least a 4 point with door bars (possibly swinging). And now I know that there are places that have good ones. However, I'm going to check with a local builder to have them put it in.

 

Great thread. Great forum!

 

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Pete Paraska - 73 540Z - Marathon Z Project - E-mail: pparaska@tidalwave.net">pparaska@tidalwave.net -

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