"Sub frame" connectors

[online170]

If you look at the chassis stiffening kit from Hellwig (Frame FX) for a CHEVELLE (not the G-body kit), this is in my opinion the most elegant and least invasive way to achieve strength for very little weight penalty.

If you have studied what our chassis needs to be stiffer, they pretty much hit the nail on the head. You want that bottom rail of the C-channel to be as wide and thick as possible. Dont waste time or weight with the top of the rail, it is nothing compared to the strength added by the body. But anything you can do to the bottom will greatly improve stiffness.

Relating that to the 2x3 square tubing example. Im not sure if its easier to use tubing or what, but it basically adds a ton of weight in less than optimal location, so you are adding weight and not getting the most out of it. If you search Mike's threads for his SFC's they bolt on below the frame rail slightly, and so are probably even more effective.

Additionally, if you study the A-body frame and the G-body frame, you can see that the bottom of the rail is basically half the width in our cars. For the least amount of money and weight, you should;
1) Try to add material where GM removed it in the G-car by comparing with an A-car
2) Make that bottom rail bigger
3) Add roll cage

In my opinion, those are the 3 steps to achieve stiffness in our cars starting with least cost/weight and working your way up if its not effective.

 

[pagrunt]

If you look at the chassis stiffening kit from Hellwig (Frame FX) for a CHEVELLE (not the G-body kit), this is in my opinion the most elegant and least invasive way to achieve strength for very little weight penalty.

If you have studied what our chassis needs to be stiffer, they pretty much hit the nail on the head. You want that bottom rail of the C-channel to be as wide and thick as possible. Dont waste time or weight with the top of the rail, it is nothing compared to the strength added by the body. But anything you can do to the bottom will greatly improve stiffness.

Relating that to the 2x3 square tubing example. Im not sure if its easier to use tubing or what, but it basically adds a ton of weight in less than optimal location, so you are adding weight and not getting the most out of it. If you search Mike's threads for his SFC's they bolt on below the frame rail slightly, and so are probably even more effective.

Additionally, if you study the A-body frame and the G-body frame, you can see that the bottom of the rail is basically half the width in our cars. For the least amount of money and weight, you should;
1) Try to add material where GM removed it in the G-car by comparing with an A-car
2) Make that bottom rail bigger
3) Add roll cage

In my opinion, those are the 3 steps to achieve stiffness in our cars starting with least cost/weight and working your way up if its not effective.

I checked out the '68-'72 kits & saw where they are added. I know the '78-'88 kits would be simular. From what everyone who has used them gives them praise. This was just an idea on an alternative to fully boxing the frame. My theory was if the frame had additional strenght from adding front tp rear "sube frame" connectors welded directly along the frame front to rear that it could reduce flex just enough to improve some of the ride & handling. From the replies it sounds like Ill have to rethink this idea. If GM didn't make the frame so flexible from cutting weight from the cars we would most likely never need to worry about stiffening them unless for hard core racing.

 

[motorheadmike]

You aren't wrong for thinking the way you are. Hell... welding in a box under the C-channel would work too.

 

[pontiacgp]

whatever you do make sure you have lots of braces when welding on the C channel area. I braced my frame when I boxed the frame but had to use straps to pull in the C channel when put the car back on the frame. The frame bowed out at the C channels