Converting Unibody 4th gen to Solid Frame?
09-06-2008, 06:01 AM
#1
Converting Unibody 4th gen to Solid Frame? Here's another idea that's a bit out there. I've been working on variations of this idea for quite a while. At first I wanted to add some square tubing into the factory rails and weld them in solid from wheel to wheel. This was originally going to be like a super sized sub frame connector. It would put all other SFC's to shame, but why stop there?
Why not extend it front and rear like a C5 or C6 frame?
Then you can do all kinds of neat things like flatten the floor boards, connect your roll bar to it, brace your suspension parts to it, ect... It will make the car stiffer and safer. Not to mention freeing up the space that the sheet metal took up.
It may sound crazy, but not any more so than sticking a C5 drivetrain under a C4 body.
Why not extend it front and rear like a C5 or C6 frame?
Then you can do all kinds of neat things like flatten the floor boards, connect your roll bar to it, brace your suspension parts to it, ect... It will make the car stiffer and safer. Not to mention freeing up the space that the sheet metal took up.
It may sound crazy, but not any more so than sticking a C5 drivetrain under a C4 body.
09-06-2008, 10:17 AM
#3
Most of that work was done in converting my F-body to a Super Stock car. the new frame extends all the way to the rear of the front subframe. Rules requirements for the class prevented completely converting the car to a full-frame configuration. One of the most important considerations for such an operation is keeping the weight down. If you use mild steel tubing you'll have to keep careful tabs on how much weight is going in and how much is coming out.
We used chromemoly round tubing as specified in the NHRA Rulebook for ET's down to 8.50. At the time we built the car it was good to 7.50 but the rules changed a year or so after it was completed. It has narrowed rear frame rails to accommodate the tubs and a full cage system that extends from just behind the radiator to the rear-most crossmember.
We used chromemoly round tubing as specified in the NHRA Rulebook for ET's down to 8.50. At the time we built the car it was good to 7.50 but the rules changed a year or so after it was completed. It has narrowed rear frame rails to accommodate the tubs and a full cage system that extends from just behind the radiator to the rear-most crossmember.
09-24-2008, 08:15 PM
#5
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+1- at least the weight you are adding is down low- I like the idea of strengthing the perimeter- If I got that far into it, I would put the cage/roll bar in, too-
Nice work, if you have time, a shop, and a few $ to spend-
Nice work, if you have time, a shop, and a few $ to spend-
09-24-2008, 08:17 PM
#6
at a show i saw a 4th gen camaro on a 1st gen frame. im sure it was a good amount of work but it looked nice. it was back-halved but im sure all they bid was channel the underside of the body like the floor board area over the frame. having no strut towers looked nice. it was at the super chevy show in joliet, IL. it was yellow and i have seen it on the internet somewhere before.
09-24-2008, 11:43 PM
#7
at a show i saw a 4th gen camaro on a 1st gen frame. im sure it was a good amount of work but it looked nice. it was back-halved but im sure all they bid was channel the underside of the body like the floor board area over the frame. having no strut towers looked nice. it was at the super chevy show in joliet, IL. it was yellow and i have seen it on the internet somewhere before.
I might pick up a stripped shell (front half anyway) from a junkyard and flip it upside down. Then cut away the stock rails and make new rails that fit nice. Then on my car hold the new rails up to the stock part and trace my cut lines. Cut it out, slide the new rail into place and weld it in. That will at least take care of the front.
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09-25-2008, 01:36 PM
#8
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If you're not going to be modifying the front suspension then
why not just do like the factory convertible and add layers
from the outside?
I have worked on full-frame cars (GM A-body) and while the
rails are decently stiff in bending, there is really no help for
torsion - that is all taken by the body shell (and being on
rubber mounts, not too stiff). But anyway, while full fore/aft
rails will stiffen the body against sag, they probably will not
make the chassis any better (or not much) for torsion.
The unibody 4th gen, even my 'vert, is well stiffer than the
full-frame 'verts I have had (A and B-body).
why not just do like the factory convertible and add layers
from the outside?
I have worked on full-frame cars (GM A-body) and while the
rails are decently stiff in bending, there is really no help for
torsion - that is all taken by the body shell (and being on
rubber mounts, not too stiff). But anyway, while full fore/aft
rails will stiffen the body against sag, they probably will not
make the chassis any better (or not much) for torsion.
The unibody 4th gen, even my 'vert, is well stiffer than the
full-frame 'verts I have had (A and B-body).
09-25-2008, 06:56 PM
#9
Every part of the suspension will be modded. I may convert over to short spindles and remove the fender wells.
Look here. https://ls1tech.com/forums/suspension-brakes/982900-has-anyone-converted-short-front-spindle.html
I'm stiffening the whole car. I just didn't go into it in this thread.
Look here. https://ls1tech.com/forums/suspension-brakes/982900-has-anyone-converted-short-front-spindle.html
I'm stiffening the whole car. I just didn't go into it in this thread.
09-25-2008, 07:49 PM
#11
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at a show i saw a 4th gen camaro on a 1st gen frame. im sure it was a good amount of work but it looked nice. it was back-halved but im sure all they bid was channel the underside of the body like the floor board area over the frame. having no strut towers looked nice. it was at the super chevy show in joliet, IL. it was yellow and i have seen it on the internet somewhere before.
09-25-2008, 08:10 PM
#12
My concept idea:
A more realistic result that can be driven:
Last edited by JasonWW; 09-26-2008 at 01:58 AM.
09-26-2008, 02:58 AM
#15
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usually when people build something like this they remove the entire floor and existing frame rails. then start from scratch and drop the body on.......why your approaching this like a mad scientist is beyond me
09-27-2008, 08:43 AM
#18
OK, how's this for an idea? I can hunt around and get a cheap firebird (flooded, blown engine, etc... ). Strip it down to the shell. Then I can brace up the interior so it will hold its shape. Then cut out the front and rear floor pans. I can build a complete frame out of two by four tubing much like the C5 Corvette as well as add a rollbar and extra bracing.
Once it's ready, I can transfer my interior, fenders, hood, doors, rear hatch, front and rear bumper covers, engine/trans, etc... over to the new chassis. This way if I give up halfway through, my original car will still be in one piece. Plus I can still drive it if I want.
Opinions please.
PS.
Could I use a cheap 98+ Firebird?
Would the 93-97 be the same body shell?
Would their k-member be the same as a LS1 Trans Am?
Once it's ready, I can transfer my interior, fenders, hood, doors, rear hatch, front and rear bumper covers, engine/trans, etc... over to the new chassis. This way if I give up halfway through, my original car will still be in one piece.
Plus I can still drive it if I want.Opinions please.
PS.
Could I use a cheap 98+ Firebird?
Would the 93-97 be the same body shell?
Would their k-member be the same as a LS1 Trans Am?
Last edited by JasonWW; 11-19-2008 at 11:33 PM.
