Tom 400 CFI

I'd like to use a stick of 3" sq tube, 1/8" wall.

I want to use the plasma cutter to slice it in 1/2, so I have two pieces of 3"x1-1/2" channel basically.

I want to notch the channel w/the appropriate angles and bend the channel to follow the floor pan, and weld the notch/seams after bending.

I then want to weld this formed structure to the floor pan, channel side up...
[___]
...from the LCA boxes, to the transverse "frame"/box behind the front wheel wells.

Lastly, I want to repeat the whole process to install the same thing inboard, on either side of the tunnel. I can then tie them all together w/a transverse member that doubles as a trans mount and a torque arm mount.

I think this would make a sweet jacking point, it would stiffen the chit out of the floor pan, and it would be way stonger than any after market set up...that I know of.

Any comments?

-Tom

83 Crossfire TA

iTrader: (2)

We did that on one of my brother’s car, but we used some 3” x 1.5” U channel used to rack mount equipment at a television station. And it wasn’t an f-body.

FWIW, subframe connectors on 3rd gens really need most of their stiffness in the vertical plain, not horizontal, so making them wider then they are tall doesn’t really buy you besides make them unnecessarily heavy and get in the way of the exhaust.

Rick King

Have you thought of x ing the fram and ladder bars?

Tom 400 CFI

'83, how did the channel you used on your brothers car work out?

Good point about the vertical plane... I know that you're right about that. I just want to minimize protrusions ffrom teh bottom of the vehicle. But that statement is making me think about going taller.

Rick, I think and "X" woudl be the best, but not sure about room under there w/exhaust. I honestly don't even know what a "ladder bar" is. I probably do know, but can't put the term w/a pic in my head.

-Tom

MrDude_1

sounds really heavy... and like 83 Crossfire TA said... you want something taller, not wider..


what about something like the convertible bracing, only thicker gauge metal?

Tom 400 CFI

Isn't that basically just strap? Tacked vertically to the rocker/floor pan seam?

I'm looking for way more "structure" than that, if I'm remembering correctly what the convertable bracing is.

I welded SSM SFC's into my last F-bod...my Trans Am. They made a big difference, but I'm looking for more than that even.

-Tom

MrDude_1

yea, its made of some pretty thin gauge sheet formed into a U..... but something similar in shape, but stronger, like the box tubing you're talking about, would work great.. both as a stiffener, and a jacking point.

dahaus

I did the almost the exact thing you are talking about, but I used, if I remember right, 2 1/2" square tubing. On the drivers side, it fits perfectly with a straight piece of tubing. I comes down about 3/8 of an inch below my ground effects, so not only is it a good jack point, but it is also protects the ground effects. Unless you look under the car, you don't notice them.

On the passenger side, it was a little more complicated. I still used a staight piece of square tubing. I had to notch out the floor pan and weld the floor pan directly to the SFC. At the front, I had to do some fabricating for the exhaust.

The turned out very nice and work great. I have never had a stiffer chassis without a roll cage. I will probably do the rest of my projects this way. It is cheap and works better.

Tom 400 CFI

Thanks dahaus...that was a great post. More good food for thought.
What wall thickness did you use?


-Tom

dahaus

I don't remember. The tubing was actually a set of SFCs for a tubbed Camaro. They had been setting at the shop for a few years and I decided to cut them up.

83 Crossfire TA

iTrader: (2)

OK, but it was a totally different chassis where he could run that channel straight from the front subframe back to the rear one, cradleing the torque boxes and not getting in the way of anything. Well, we did use a jack to move the back seat, driver’s side floor up a little to get it out of the way.

It’s not possible to weld all of the U in without pulling the interior, and if you’re going that far with an f-body I’d use box steel and cut the floor so that it ran through the floor and was welded all around.

Tom 400 CFI

I hear you '83 CFI. I've considered that too, for sure. I'm going to think about this all mroe before I make a move. How far up in the passengers comparment do you have the sq tube intrude?

-Tom

83 Crossfire TA

iTrader: (2)

Do a search on this board… I know that there have been pics of people doing it this year that are about as good as I’ve seen. Typically you need about an inch in most places, which is little enough to not really interfere with interior bits and pieces once you cover it with carpet/carpet padding.