I started looking into it a bit and I've read in books about the 4th gen convertible. Evidently it wasn't ready in 93 (4th gen verts came out in 94) b/c GM was using a computer model to predict all the major stress points that would be present in a roofless car. They knew that previous gen convertibles were not that stable and corrected it by adding reinforcement in particular areas. Hence the 4th gen vert is the "most rigid camaro ever built". But they never mention exactly what they did to make it that way. I can;t find any specific info about what they did.

Chevrolet built all 4th gen verts (not ASC). So you'd think any added braces/members would be available to at least look at and get an idea of what they did.

I've seen the added frame braces GM used on the C4 verts. They used a huge x-brace along the bottom and three extra side to side reinforcemnets from front to back (a "wonder bar", k-member reinforcement, and a brace that attaches the rear shock towers).

But no one mentions whats been added to the 4th gen verts. I cant find a schematic of the 4th gen vert chassis. Can anyone help?

 

I can support GM's claim as my buddy has a '95 Z28 rag top and it has no irritating squeeks or rattles with the top up or down.My car on the other hand..........

 

If you can, take a look underneathe the car and see what you can see. Is there a factory "x"-brace under there?

I really need to look in a chilton to see if there is any info there.

 

thought there might be a little more interest in this subject, but oh well. Here is some info I found; Yes, chevy did construct the convertibles at the GM plant (not ASC), BUT, ASC did supply the top and the additional bracing.

The added bracing included a rocker panel reinforcement, a rear brace that runs between the wheel wells behind the back seat, an "x" brace that attaches to the floor pan underneathe the car (supposedly around the same place the tunnel brace is located), and some added thickness to the sheetmetal in a few places.

These pieces were not just thrown in. GM did a lot of research into this bracing (so much so, that the 4th gen convertible's debut was delayed until 1994).

I am still trying to figure out what the factory x-brace looks like. I cant find any pictures on a web search. But there is a tech article on how to do a rear cross brace. Also, check out this link for rear braces on the C4 and C5. Very interesting.

http://www.r-dracing.com

 

Hey, I'm interested! Just what exactly is a rocker panel brace and what does it look like? Pics would be helpful. I haven't ever seen an x-brace, either, although I can kind of picture what it might look like. The rear brace between the wheel wells in the back that you talk about, would this be like where the gas tank is in our cars? Does it run the width of the car or just inside the wheel wells. I've been thinking about some custom DIY chasis strengthening ideas lately, and it seems like you're onto some good info. Let me know what you find and thanks for doing the hard work!!

James

 

No longer feeling un-appreciated.

The rocker panel reinforcements are simply like the SFC's that ASC put on the 3rd gen. I don't know how similar they are in design though.

I cannot find any pics of the rear frame brace they talk about. I did see one on a C4 chassis that GM displayed in a book. The yset it up at a car show somewhere so that people could see what the new vert bracing looked like. I just looks like a piece of stamped metal that runs along the top of the panel behind the seats. I can't find any closer pics of it through web searches. There is a tech article here about how to construct one (but its for hardtops).

The x-brace is just as elusive. No one has a pic that I can find. I don't think it runs the the full width of the chassis though. SLP has an x-brace replacement piece for use in 4th gen verts that want to run a bigger y-pipe. Look through their cataloge for a general idea.

Thats all I know, man. But I am continuing to research and will keep all posted.