Sinful7

Here's the plan drawings (roughly, from P.S.) It should be good to nearly the failure point of this size (cross-section area) of steel... ~35,000 PSI. I'm not sure how much force a human body can take, but I think this will be more than enough. The only downside is the weight... all that steel weights nearly 6 pounds. (The stock brace is closer to 2-3 lbs.)

teknics

i still think tyson is correct, the whole problem with that roll bar was it's ability to bend or break in a collision....rendering anything attached to it, such as your harness, useless....or even deadly (if it bends backwards it's ripping the harness back with it and problem ******* you up as your body gets wedged further into the chair...or it could do the opposite and send you flying forward, or sideways for that matter.)



You could do what i've seen done nuder the hood with strut bar braces and make it from the lonely weak 2 point into a massive yet superiorly strong 4 point bar....or go with the strongest shape on earth...a triangle, and make a 3 point bar



my $.02



kevin.

Sinful7

I agree 100%!! That is the function of my design above. It will eliminate the "bending" ability of the bar. There will be no flex, it would be as sturdy as attaching a harness to a roll cage, with half the size of bar. I have had engineers consult on this one, and we all seem to think that my design will be robust enough. The challenge is to eliminate any point at which there is non-shear force being applied to the hardware. My design will hold. If I can find a shop with a hydraulic press, I'll have them test the failure point of my bar.





Another good idea, I had not thought of this. I might work on a design to bring this to frution. It may actually reduce the weight, as compared to my current 2-point design.

teknics

want me to find you a pic of the 4 point under hood strut brace? I saw it somewhere, two points were on the firewall at an angle from the towers...hard to explain im sure i could find the pic if i tried hard enough looking for it again lol



also as a third point you could use the middle of the trunk...or middle of the floor right between, yet behind, the seats....just tossing out random ideas



kevin.

Sinful7

I'm curious how the bar would backward, or sideways??



The solid cylinder core, reinforced by the box tube, are exactly designed to combat structural buckling. In fact, the bar should prove to be much more stiffer on the rear suspension than the stock bar.



It only has to work once, and if the force of the accident is so immense that the bar fails, you're probably already dead.



I don't expect the stock seat belt to hold me (without disembowling a me) if I wreck the car at top speed. This vehicle was not designed to handle those sort of impact forces, let alone the safety systems. It just needs to hold, in case someone hits me on the street, at normal street speeds. The same is true for the harness. I'm not trying to build a JGTC supercar, just a street runner. I will rarely see speeds over 80 MPH, so the safety equipment does not need to be able to protect in a 200 MPH bone-crushing wall crash.

Sinful7

No, thank you.. I'm aware of the design of an underhood 4 point STB.



I would like the design to allow retention of the center divider piece, so mounting 2 addt'l points behind the seats is out. And the rear-middle trunk would have a lot of tensile forces on the bolt, which *could* be another weak point.

Sinful7

Here's the latest progress:

Sinful7

Here's the bar end:

Sinful7

and here's the bar with no trim coverings:

Sinful7

I have a design revision, and I'll be taking pics and updating as it comes along.. Hopefully I'll have it finished by next week.