Matthew91-Z28

Check it out in the suspension forum::

https://www.thirdgen.org/techbb2/sho...hreadid=229873

https://www.thirdgen.org/techbb2/sho...hreadid=229873

Speedgraphic

P L E A S E (pretty please!) give us some more (better pics) as well as any other details you can provide!

THANKS!
Speedy

Matthew91-Z28

I'm going to check out a nice digital camera from the school library today to take better pics of it.

Went driving around today. Man, I really like this mod. I'm really growing to like it more and more. Before there was alot of chassis deflection and twist contributed by the rear end. Now alot of that has been resolved. Definately noticable.

I might go so far as to say that I think I have less bumpsteer now. When the left rear tire hits a bump in the road, its stays planted instead of that side rising up and losing traction. Its weird. Still getting used to it and trying to define the changes its made to driving feel.

I used 1" 12 guage round for the cross bar. The pieces it attaches to are right-angle steel (1/4" ??). The right-angle will need to be about 2" wide. One side(horizontal) is 4", the other(verticle) is 3". Needs to be lined up so that the verticle part of the right angle sits flush with the inside of the sail panel. THIS IS IMPORTANT as there must be enough room for the seatbelt harness to fit back in.

3" should be tall enough to give a little more than 1" exposed above the sail panel. The cross bar is 1" dia, and it welded to the righ-angle so that it just kisses the top of the sail panel.

I discarded the plastic washer under the bolt and used a crush washer instead. I will probably discard the stock torx-head bolts in favor of stronger and a bit longer hex heads.

I had ONLY ONE whammy during this mod and it was only due to ASC's poor craftsmanship. The pasngr side sal panel sat a little higher than the other (maybe 1/2 inch). So I had to press down on that sail panel while my welder tac welded the cross bar in place. We tacked both sides then pulled the brace off, welded it, grinded some off the edges, painted it black, and reinstalled after the paint dried.

Yes, , you will need your top completely lowered for this. I made sure that the bracket did not interfere at all with lowering/raising the top. It works just fine.

I'll post pics and maybe come up with a tech article, if the gods that be deem it worthy.

Ovrclck350

There's a tech article for that but it's further back instead of right where you put yours. I've been thinking of doingit for a while.

Matthew91-Z28

Hey longview...FortWorth here.

The tech article, "rear frame brace", is for hardtops and uses a crossbar attached with brackets to the rear seatbelt mounts. I know of one person who has done it and has been very pleased (crazy hawaiian??).

Same concept here, but I think that a MID-chassis brace is more appropriate for convertibles. The B-pillar area is reinforced and very strong. It was calling out to me, in fact, to be braced.

No seriously, I have been thinking about this for a couple months now and am so glad I finally came up with a bracket design that would work to connect both sides.

My intention was to decrease mid-chassis flex (as we don't have a rooftop to prevent it). BUT I did NOT expect to get this big of a decrease in rear chassis flex. The mounting points on the b-pillar must be about 20" from the shock towers but the connection is solid.

Its one of those mods that makes driving fun.

Ovrclck350

I just wouldn't like the lack of access to the back seat....I've thought about the same idea, but in 3 different locations, just never got around to doing it.

1. Right about where you put it, but lower near the floor.
2. Actually WELDED to the sides underneath where the top folds down, and then wrapped around the back of the seats.
3. Further back in the trunk, right behind where the top falls.

Matthew91-Z28

Yeah...my backseat never gets used anyway. Just an extra 100lbs of leather that makes the car look nice. And with it sitting where it is, it makes a great future 5-point harness brace.

Well, you are on the right track. The area behind the rear seats is one of 3 areas GM focused on strengthening in 4th gen convertibles which debuted in 1994. Not sure what they did though. They did the same thing in C4 verts....extra reinforcement between the shock towers.

What size tubing are you thinking about using?

From pics I've seen of the C4 added reinforcement, I would prob just weld a piece of 2" square 12 guage along the sheet metal b/t the shock points. What do you think?

Matthew91-Z28

This is what I'd like to add on top of mine::

http://www.r-dracing.com/C4STFS_023.jpg

IrocZonNos

Who makes thi type roll bar?

Matthew91-Z28

Which type brace?

The one in the link is made by r-dracing.

The one in my car in the pics (links in the first post by me) was made by me. No one sells one for thirdgens. Its a custom bar.

Matthew91-Z28

Has anyone else attempted to fab one up yet??

I LOVE the way my car handles now. I can't wait to get up in the morning to drive it. It feels like it "pivots" in the rear end when turning. Much sharper crisper handling. Better lines around corners. Holds together so very nicely.

Man, you guys have got to do this soon. Its an easy mod and cheap ($30).

The hardest part was thinking of how to get a bracket in there. As soon as I pulled off the garnish molding, I instantly saw how to make it work.

You will too...

Here is a rough cross section::

Blue=seatbelt harness mounting plate (each side has a bung that the harness actullay slides onto that the bolt goes through). This is the bung that your brace will slide over (under the seatbelt harness).
Red=sail panel
Black=crossbar