Targa brace

[Isphius]

What if you took the 2 end plates that you have, And just ran parallel tubes from front to back along the windows, With little gussets to prevent it from bending? It would just be like if you cut a sunroof shape out of the targa top to simplify it. i was doing some mechanical engieering research, And the force applied to the roof section isnt what i thought. Its the obvious front to back (windshield and rear section trying to touch each other), But it would have to apply the same force for the car to twist, unlike the side to side bending i thought. The front and rear sections of the car generally pretty stiff already, So they will not bend on their own. They Just allow the car to bend at its midpoint. So All you would need is the brace to be stiff front to back, Not torsionally or horizontally. For example...hold a block in your hand (like a lego, box of food, Anything and try to move your hands front to back. It makes the box want to spin, And apply force front out towards your hands. That means you could make that thing way smaller and it would do the same job lol. Sorry if this is boring...

[theWeezL]

Well to answer some of those questions:

The Brace weighs 18lbs. (The targa top weighs 26) There is not extra weatherstripping on the rear bar where it rests on the factory seal. The way the top bolts down there is no rubbing happening there so I dont see how it would wear the seal any more than putting the top there.

Isphius, I know what your saying but there are at least two reasons why what you mentioned would not be something I would want on my car. First of all, the point of the bar as its designed is to allow the driver the feel of having the targa top off, while maintaining chassis rigidity. So a bar going essentially across the top of the door glass would in my opinion not be very elegant. If you have a targa you know how when the top is out and you go to sit in your car, you can grab the front windshield and sort of slide into the seat....no ducking under the roof...I like that and want to keep it. Secondly in regards to your description of the kinds of forces involved in chassis flex and which direction you need to brace against, your not entirely correct. Yes you definately want to brace against the action of the windshield and the roof coming together, but in terms of the most benificial to handling of the car, the twisting action is by far the most important, and the reason is pretty simple...sway bars.

Sway bars work by linking both sides of the suspension together. Basically doubling the spring rate of any given corner, by distributing the force to the other side through the sway bar. This creates tremendous forces laterally AND diagonally across the vehicle. When the targa roof is in place it bears the load of these forces across its structure, essentially connecting not only front to back, but front left to back right and back left to front right, etc.

By welding the two curved bars in the middle I provide a transfer point for this stress in the middle of the car, (the two big "U" shapes become one "X" shape).


Cliff notes: bar is 18lbs, no wheatherstripping (doesnt need it) bar needs to be the shape it is for chassis strength (door bars would look ugly and not bear the load properly)

[Isphius]

Well yes thats explained well, But what i was saying is the forces are applied to that section of roof differently than i thought (remember up there me saying it looks too wimpy, because i thought it was a bad shape, but now i realize its just fine). And I do know what you mean about the sliding in thing, It is fun (i had an 83 trans am with t-tops and a convertible lebaron to drive before) But I was thinking that itd be cool Just because there is nothing above you. I will try both out when i get to drive my turbo around (its a targa). I need dam money to finish it!

[SupraSaver87]

I am wondering how much for the brace..or have you not ordered a whole slew of them yet?

Anyways, I am interested in that...I need something like that, for what it was meant to be...a targa top feeling opening...

[theWeezL]

I am having some changes made to the design. I should be getting that back in the next couple of days. Once I do I am going to order 20 of them and have some for sale. I may already have the first 20 sold already because of the interest on another forum. I'll try to be able to offer a few on here, but I may not have any until the second run of 20 is placed (about 3 weeks from now)