OreoLT1

I want to do the t-top conversion to my 00 f-body but I am wonodering what differences the frame structure's hvae between the t-top and hard top models. What will I need to do to bring my frame integrity to acceptable limits to compromise for the loss of the hard top?

97FormulaWS-6

A Hard top car just has a full piece of fiberlass or sheetmetal over the frame of the T-Top; they are the same car, one just has the extra material, nothing structurally different between the 2.

Ken S

Don't forget that thin piece of metal across the edges to give a little extra support for the roof on the edge, but its not gong to add a whole much more strength.

So in effect, Formula is right.

lateapex

I disagree. Cutting out the 2 steel box sections (over the side windows) that tie the A and B pillars together will substantially weaken the entire structure. This chassis is a monocoque, not body-on-frame construction. Most of the chassis is fairly thin stamped steel, but with crucial ridges and bends which provide it adequate rigidity. If you look at the cross section of those supports, you will see that they are fairly large, have a complex construction, and are of a similar gauge steel to much of the monocoque.

From outside analyses (and manufacturers specs) of other sports cars, I would suspect around a 10% loss in longitudinal (bending) rigidity, and close to a 20% loss in torsional rigidity. Sacrificing the one-piece bonded SMC roof panel also figures into the total loss. You could regain a portion of your losses with some very serious welded subframe connectors, but you could not regain all of the original rigidity by simply bracing in the plane under the floorplan. Well, reasonably anyway. Maybe 200 lbs of strategically welded “C” channel or deep rectangular tubing could restore it.

Look at some of the pics of a conversion to see the size and gauge of the supports you would be cutting away:
http://www.geek-racing.com/curt/T-to...on/ALBUM1.HTML

I have spoken with people who have owned both models, and they can feel a real difference. One owner had subframes installed on his brand new T-top F-body because he did not want to create excessive fatigue by driving it "unbraced". He said even his new, subframed T-top car had much more cowl shake and flutter than his 4 year old coupe without subframes. He said going over RR tracks the difference was enough for his friends (passengers) to notice.

Z28barnett

I knew I ordered a hard top for a reason.

Looks like a bad idea to cut out those roof beams.

If you think of the car as a tube, the metal at the extremes from the center of the tube is the most efficent at stopping the bending of the tube.

Bob has it right, and you will get leaks and rattles. You will have enough things to fix without adding problems.

I vote, leave it alone.

Z28