[Jamie]

I have a quick question and would appreciate any advice. I am building a 67, the car has a heidt's front clip, it is mini tubbed with a narrowed 9", it is four linked and has weld-in subframe connectors. the motor is an aluminum headed big block that makes a legitimate 531 hp and 586 ft/lbs. The numbers are accurate as the motor was tuned on a super flo dyno. My question is this: Does the car need a cage? It's not a race car and will be driven on the street. I am however concerned with the car twisting. Any help or advice would be greatly appreciated.

 

[luepke75]

If your not racing it I think your fine. When I put my sub connectors in it made the alot car stiffer but my motor was only pushing 410hp. I have a cage now but only because I plan on raceing it with 250 shot of juice. IMO on the street the cage is a pain in the butt getting in and out and I have swingouts. I have a back seat but forget about useing it.

 

[Jamie]

Thanks for the reply. I was considering putting a main hoop in the car with the forward diagonal tube and was going to try and avoid loosing the back seat as I need the back seat for my son.........So, I guess ultimatley it will be a street car with a fairly strong motor. Thanks!

 

[luepke75]

Yea I worry about the cross bar that goes behind the front seats. In my car its face level if I got rearended. You could do a hoop and forward struts. It would make it stiffer but for the street not needed.

 

[TechGuy]

. the motor is an aluminum headed big block that makes a legitimate 531 hp and 586 ft/lbs. The numbers are accurate as the motor was tuned on a super flo dyno. My question is this: Does the car need a cage? It's not a race car and will be driven on the street. I am however concerned with the car twisting.

If it has race car power...it's still a race car .. if you get on it enough,
it will some day hurt the car, ..or you.
Remember.. some one out there proabaly likes you.

If it hooked,its a high 10 second car, so treat it like one.

 

[74 hatchback]

should be caged but would do fine with a loose convertor and some street tires, need something to soften the blow, i wouldnt solid mount engine/trans either.

 

[luepke75]

When I said if your not racing you should be fine that should include on the street as well. But like these others have said if you get on it the power is there to do some damage.

 

[D-Man]

I would say it depends on the type of mini-tub/back-half that was done. If it was just mini-tubbed and the frame itself was unaltered then no biggie.

BUT....

If it was frame clipped or the framed was sectioned and/or narrowed in any way then it NEEDS the extra bracing of a cage!!

The back bar and door bars can be gusseted and pinned for removal. It's the main hoop, rocker bars and back bars that will be the most important for your needs.:yes:

 

[Mike in Motown]

In my opinion the second gens torsional rigidity on a scale of 1-10 is a 2 or 3.

My 67 is still in the build stage but funny how it moves simply by jacking in different places. Mine is mini tubbed and will have 400-450hp but I want to run slicks occasionally at the strip. With the manual trans i know I'll have issues without a cage. Problem is I dont really want one for the street. A buddy has a 69 camaro with 500hp manual trans and has cracked/torn both rear quarters by the back windows. Another guy has a 66 with a BBC and always has door alignment issues without a cage.

And theres the problem of a cage and no helment causing more safety issues on the street than it prevents.

Im still undecided. Let me know what you do.

 

[MarkW]

I've got a full cage in my 67 Camaro and I worry a lot about what would happen in an accident. Sure the car is nice and stiff now but there's a lot of steel bars for me to bounce off off. They're all padded but I am very aware of the halo bar when I drive with no helmet. A roll bar with door bars (8 point?) would be much safer on the street.

 

[TechGuy]

I've got a full cage in my 67 Camaro and I worry a lot about what would happen in an accident. Sure the car is nice and stiff now but there's a lot of steel bars for me to bounce off off. They're all padded but I am very aware of the halo bar when I drive with no helmet. /QUOTE]

Your head is gonna hit the window or the door any way in an impact... a padded tube would be a softer hit... assuming the cage is built & installed
correctly.

Installing less protection for comfort is like turning off the AirBags in your car because they might go off accidently... if you need them, your S.O.L.

 

[Mike in Motown]

I guess this question for Mike W isnt off topic. A few weeks back at pleasanton there was a first gen right beside the Chassisworks display. Did you guys do that cage? I couldnt tell if it was part of your display or someone parked beside. I ask because that cars cage was tucked up in TIGHT. For street driving the only thing to bounce your noggin off of is the main cage upright in that car. It looked race but would be ideal as far as a cage goes for the street. Except, I dont know how you would ever get a headliner in it.

 

[JRouche]

A cage isnt installed to stiffen up the chassis, its a protection device. Read Chassis Engineering. The book talks about several methods of stiffing the chassis. A roll cage doesnt help as much as a properly designed pan really. Which really surprised me. I always thought a roll cage made it a solid unit. Wrong. So if you think about it, the strength of a cage for the chassis stiffness has to travel a long distance. And the bars just arent positioned correctly for chassis stiffening. Great for a roll over, the impact load is applied to the pan, and with proper side bars they help with side impact.

But for chassis stiffness think of the car as a pan, with the front and rear control arms attached to this pan. You want to keep this pan from twisting. Vertical bars and diagonal bars going up to the roof line dont add much in the way of keeping that lower pan from twisting.

Ideally, IMO, would be a box frame. A lower heavy walled tube frame for the lower and an identical frame above, separated by say 8" and linked together with bracing and sheetmetal fully welded.

It would be as long as the wheel base (longest control arm mounts actually) and as wide as the track (again, only as far out as the C/A mounts). Think of a large rectangular box with the control arms attached to this box. No twist. Very heavy and not practical.

Well thats not practical, it would encroach into the entire passengers compartment, or raise the car to a crazy height for the body to sit on this solid platform..

So there is a compromise. Start from the best situation and whittle it down for practical use. We can do the lower frame section of the box, thats what many full frame cars are. But that alone is still kinda weak.

So think about making the "PAN" stronger. Try to build back up to that simple rectangular box configuration. Add where you can, keep the weight as low as you can but still use some of the ideas of the box. The front and rear are easy, there is room.

So, we dont wanna add the top section of the full box, just wont fit and the weight doubles from the single plane frame thats in place. So look at maybe working on the vertical sides of the box, attaching them to points in the car where the upper section of the box frame would be. So it doesnt have to be high, shouldnt be really, the higher you go the less rigidity you get. Think about that 8" tall box.

The weakest spot?? Well open your door. There it is, look at the floor. All it has is the frame and the roof.

And thats why guys see a cage as an obvious improvement because you have a tube "helping" out with this weak link. But unless you are putting in a full nascar cage then the additional stiffness gained from the roof bar is minimal. Even a welded in diagonal door bar isnt helping much with the pan twist. Helps with frame bounce, fore and aft, but not really at all for flex side to side. Left front in relation to right rear.

So what do we do to bridge this gap in chassis stiffness????? Great question... Holy grail of chassis builders.

There are some engineers that are on top of this. And Im not talking about purpose built cars, race cars. Thats easy, clean slate, build a monocoque structure. Im talking about our cars.

Ok, so there are some engineering guys that are on top of this for us too.. I like the idea of a multi tube design frame. With these you can get a box frame within a small area. So in essence is like the 8" box frame but smaller. Upper and lower tubes connected but much closer. Still get a solid boxed pan, but much "thinner" to work with the cars we use..

I have some ideas Who knows.... Im not gonna build it, but I think some are... Alright!!!!! I know, I went off on a tangent.... Solly Umm,,, Cages are for protection, not chassis stiffening. As I look at my sagging frame LOL JR

 

[luepke75]

After reading the last post very informational by the way, isnt that what the sub connectors do? Stiffen the pan. I noticed a diffrence with my cage installed.

 

[hotrod69nova]

I would say cage it.even if you are just running it on the street.it is still safer with a cage than w/o.you should still be fine without one though.

 

[hotrod69nova]

a cage looks cool too.

 

[luepke75]

a cage looks cool too.

Now thats something we all can agree with.:yes:

 

[TechGuy]

I guess this question for Mike W isnt off topic. A few weeks back at pleasanton there was a first gen right beside the Chassisworks display. Did you guys do that cage? I couldnt tell if it was part of your display or someone parked beside. I ask because that cars cage was tucked up in TIGHT. For street driving the only thing to bounce your noggin off of is the main cage upright in that car. It looked race but would be ideal as far as a cage goes for the street. Except, I dont know how you would ever get a headliner in it.

The primered Nova cage was a custom built by Roger @ IronWorks.
Most cages actually fit good if the time is taken to fit them.
The headliner goes in first in most cars

 

[383Nova]

If it has race car power...it's still a race car .. if you get on it enough,
it will some day hurt the car, ..or you.
Remember.. some one out there proabaly likes you.

If it hooked,its a high 10 second car, so treat it like one.

I have all the respect in the world for Mike and could not agree with him more on this.

Joe

 

[383Nova]

Taking you time and fitting the cage is the key to a good fit.

I did have a custom built cage for my car because I wanted it tucked up and away as far as I could. I wanted a rear halo. I wanted the main halo to be the two door/roof bars and the front window completing the top halo.

I to drive my car on the street but still know it's a race car first and then a street car.

My car is now NHRA cert for 8.50. The guy had nothing but good things to say about the work done on the cage and the bar location. My goal was to have a rool cage to save my life and allow me the best chance to walk away and I feel this was done. I love the fact it blends in so well from the outside of the car. You only see two bars from the side window.

Joe