[QUOTE=JasonWW].

I haven't been given ANY options in this thread.

Well, that I don't agree with.
And just to point out the obvious-this is the "Drag Racing Tech" section, we don't talk "speakers" in here unless we're pulling them out of the car.
Sorry you didn't like our replies but I think it's more you didn't hear what you wanted.
And BTW-I only asked you one question and you ignored it-who's the hottie?

 

Well, that I don't agree with.
And just to point out the obvious-this is the "Drag Racing Tech" section, we don't talk "speakers" in here unless we're pulling them out of the car.
Sorry you didn't like our replies but I think it's more you didn't hear what you wanted.

 

They only reply I had any emotion over was the rice comment. I don't like hearing that. I'm sure no one does.

Your right about me not hearing what I wanted. I asked about how to maintain visability and got no answers at all. So that sucks. I was hoping to find some technically minded folks who might have some suggestions, but all I got was "it can't be done". It's OK though, even I can't come up with a good solution.

 

 

I'm done trying to help you. Theres some pretty good info you have been given by some people. Just cut your roof off your car and mount your exhaust tubing higher up. Good luck on your build.

 

Keep the replies on topic. While his need for a roll bar is not necessarily Drag Racing related, it is a valid question none-the-less. 99.9% Of everyone here doesn't really see why one would need a roll bar in your application.

I've been thinking about your application off and on over the last couple of days since you put the post up. A couple things have come to mind. Some are questions to help gauge what you are doing. Others are statements as to how you could get what you are potentially looking for.

What about a roll cage makes you think that it will make your setup any safer? Even in a 70MPH drift, a roll over in a car that weighs close to 4000lbs with a low CG is going to be a decent stretch. Can it happen? Potentially, but not all too easy unless you find a ramp. Is this really your primary desire to have the cage, for a roll over? In general, the F-body has a pretty beefy integral roof beam that will serve it's purpose in the event that you manage to pull off a immelman with your car. I don't believe that a roll bar would do anything in your case that the car itself won't do for you already as is.

I'm 6'5" and with my main hoop I never really had issues seeing out the back window with my mirror until I put a 10 point cage in. With a 6 or 8 point cage you should still be able to see below the main hoop if it's installed high enough. Your height will have everything to do with that.

You don't necessarily need the cross bar behind your seat if you are not going to be doing anything that requires a real roll cage. If you're primarily concerned about a roll over, the hoop with a pair of swingouts and the rearward bars would be enough. You can use subframe connectors to keep the primary portion of the body rigid enough that you could just get away with a main hoop and two rearward bars. Where those bars land and how they're configured. For many show car setups, they actually do more to make the roll bar stand out than to be hidden. Here's an example of one.



You could certainly go that route, but the way the bars are configured in the back will surely make your rearview mirror nothing but a map light. If you didn't want bars like that you could simply sweep them to the back and outward to the sides of the t-top well. That won't effect your rearward vision at all. Here's an example of one.



For the most part you can get what you want. But it would likely require something a little more custom for your needs. That doesn't mean that it would necessarily cost you more than a standard cage though.

When it comes to mounting your equipment, it would be far better to consider through body mounting where you can. The sheet metal on the car is quite durable and will certainly be able to hold your stuff down quite well. Some things can certainly be mounted to the cage, but in all liklihood you would end up with having a cage that would be so far spaced out to the sides that much of it would be useless for mounting any equipment to.

Your best bet would be to sketch out the layout of your car, where you want all your components to go. Then sit down with a local fabricator and see if they can put together something for you. Definitely get the cage installed and painted first unless you're ok with stripping all your components out of the car before getting it done at a later date. The grinding dust and even the welding on the car will not be all too spectacular on your car. Ultimately you need to find something that looks like what you want first and then work your way back from there.

As for the rice comments, only you will have to answer to those in the end. If it's done tastefully, most people wouldn't notice too much. If it starts to look like a race car, well, you can imagine what you would have to put up with.

Good luck.

 

yeah, my mirror is basically useless too

 

I only have a few ideas so far. Besides using a LCD and a camera to see behind me, what about compressing the middle of the top hoop to make it oval shaped instead of round? I'm not sure if it could be done on a press or maybe heated and squished, but basically take a 1 3/4" tube down to 1" or so. Not totally flat, but flatter. If there is any room at all above the headliner I might could just press the top hoop against it and let the headliner bend upwards some to squeeze a little more height out of it.

Another thought would be to make it from rectangular tubing. Say 1"x 2" .187"
I've never seen that done before. Would it have the strength of the round tubing?

 

There's no air gap above the headliner. Just two layers of moderately thick structural sheet metal. There's the inner skin to the roof of the car and then the exterior skin is above that. The exterior portion supports the plastic roof panel, which is glued on. So, unless you cut that out to put the roll bar above the headliner (which is probably not a good idea for a street car) then you're SOL there. Not to mention your seat belts and everything is tied into all that material. I'd rather leave that intact because it is a part of the crash structure for the car.

I wouldn't ovalize the tubing. #1 - It would take the structural strength right out of it and make it just as useless as not having one. #2 - It would take a hell of a press to consistently ovalize 1-3/4 .083 wall tubing. This is something your average shop won't have, or even your above average shop. Heating and squishing it is a bad idea in general because the heat will anneal the tubing and make it softer.

Rectangular tubing would be rough to do. It would also look tacky IMO.

You're fighting over 3/4" and I honestly think that you're blowing it way out of proportion. The top hoop of the roll bar does not obstruct your view as much as you think it will. You'll be able to see out just fine. Not to mention you have two other mirrors to work with.

 

Why do you assume I haven't measured this stuff? I know exactly how much vision will be lost. I did all the measuring and testing before I even started this thread.

When you consider that the tubing is only 1 3/4" and that is exactly what is blocking all the rear view, then yes, 3/4" is worth a lot. I'm fighting for everything I can get.

If I were to cut a gap out of the lower roof panel just big enough for the top hoop to fit up in and then weld the top hoop to the roof sheetmetal it seems like that would make the whole car stiffer. It would also add to the overall stregth and compromise nothing. Custom headliners are not hard to do, but I'm not sure how it would look overall. Probably wierd.

 

The lower roof sheetmetal is the structural part. The top side is not. Your seat belts attach to the lower, not the top because the lower is the portion that is the strongest. Cutting into that material and welding it to the roll bar may in fact compromise the structure more than help. You'll have about 40" long set of stitch welds on both sides of the pipe all the way down. Assuming you alternate in 1" stitches, 20" of stitch per side of attachment. Throw in a little heat effected zone in the material and you've changed it's strength characteristics so much that the roof structure is nowhere near as strong as it was before. The addition of the roll bar would offer very little to the strength of the roof at that point because you changed it so much. Instead of being the intended energy absorbing deformable material, you'll make it something that no one has ever tested. Your discrediting the strength of the car far too much.

If what you want is your vision and you're not interested in making a roll bar to spec, make it out of a smaller diameter material.

Since you've done all the measuring and testing ahead of time, you really have all the answers that you need. I'd suggest taking it to a fabricator with your plans and have them provide you what you need.

 

I'm going to be the fabricator, just to clear that up.

I think I have a compromise. I planned on placing the top hoop a good ways back from my head since this is a everyday driver car and I don't want my unprotected head to hit it in an accident.

Because the roof is not flat, if I move the hoop forward and make it hug the headliner, it will be a bit higher. I can then lower the rear view mirror just a little if need be.

I'm going to have to add some padding on both sides just behind the headrests, just in case, but keeping the middle area clear.

Question is, how close to my head is safe? 6", 9"?

I wonder what would kill me first, hitting my head on the rollbar or the lack of an airbag? Hmmm.

 

From my tests, moving the top hoop forward and having it touch the headliner should reduce it's size by half, which should be enough.

Does anyone have any regulations on rollbars? I'm wondering if I should make a seat brace to keep it from collapsing to the rear. As long as the seat doesn't fall backward there is no way for my head to fit between the roof and the headrest and make contact with the bar.

I could have sworn someone posted a link to some NHRA rules or something about the bars, but I can't find it.

I plan to have the rear support bars go straight from the top hoop to the shock mount area. No need for fancy bends or going through the speaker holes.

Do the 4 point bars have to be 3 pieces to fit into the car? Once mine is welded together I want to remove it for finishing and then put it back in and do the final welding on the mounting legs. I'm wondering if I would have to have the back supports bolt onto the main hoop or not?

I'm assuming removal of the seats and maybe the center console to get them in, but even then, they are bulky and may have to have bolt together support arms.

I'd like to have the extra protection for a 150mph tire failure as I sometimes drive that fast. Does anyone know of any guides that show tubing size and thickness, etc... for that type of application?

Here's what I mean by having the top hoop follow the roofline. Would a rollbar maker have the tools to do such a shallow arch?