Making a C3 up to par with a modern sports car....Discussion maybe?
04-09-2007, 08:46 PM
#203
Le Mans Master
The whole setup there is lighter than just the stock crossmemer. Even so, I will put a whole bunch of holes in the larger beams. Also, the floor panels (alu) will be secured directly to the frame. The alu sheets are no heavier than the stock floor but a good bit thicker and a lot more sturdy. This will also make the whole car stiffer without a weight penalty and for me the bonus is a lower floor and a flat bottom for the belly pan, only problem is the exhaust won't fit.
Even so, this will help but only so much. Look at the C4, the X brace there works but only so much it's not the perfect solution by any means. Also, a cage is nice but only a cage that ties into the suspension mounts on the frame will have a chance of giving you any meaningful torsional stiffness.
Yes the C3 is an old ox cart, the suspension design is ancient LOL
What are huge bfgs? radial t/a's or a racing tire? Those radial ta's and most if not all those white wall tires are pretty poor. Apart from shopping in the michelin old race car tire section there are no real good streetable tires except for the ugly scorpion zero suv tire.,,,thhat yokogama tire (you know, the one available in 335) is discontinued and I'm not sure if pirelli still makes it (for the countach and panteras) if they do, that's a pretty damn neat 15" tire..but very expensive.
Even so, this will help but only so much. Look at the C4, the X brace there works but only so much it's not the perfect solution by any means. Also, a cage is nice but only a cage that ties into the suspension mounts on the frame will have a chance of giving you any meaningful torsional stiffness.
Yes the C3 is an old ox cart, the suspension design is ancient LOL
What are huge bfgs? radial t/a's or a racing tire? Those radial ta's and most if not all those white wall tires are pretty poor. Apart from shopping in the michelin old race car tire section there are no real good streetable tires except for the ugly scorpion zero suv tire.,,,thhat yokogama tire (you know, the one available in 335) is discontinued and I'm not sure if pirelli still makes it (for the countach and panteras) if they do, that's a pretty damn neat 15" tire..but very expensive.
What material did you use for the X-brace. My frame was orig. an auto converted to manual, so I know I've got plenty of work to do in that area...
The street skins I was looking at were the BFG g-Force T/A KD's, 275/40ZR17 fronts, 315/35ZR17 rears, if they still exist by the time I can swing the rims.
Last edited by TheSkunkWorks; 04-30-2007 at 07:55 PM.
04-13-2007, 06:11 PM
#204
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Exactly! And the ladder bar frames are far from torsionally stiff, in fact they are notoriously un-stiff and the corvette frame is a **** poor frame also with the flexing front suspension area, the crappy brackets, the poor welds and the rear with that awful kickup area that flexes like crazy. I tested all this before welding the cage in and I didn't even need a very long bar to flex the frame, the kickup area was the worst of all. Just pushing down on the rear resulted in a visible amount of flex. That's where the c5 &6 excell with their honeycomb (balsawood/aluminium) floor and trans tunnel being a sort of monocoque and the torque tube (a big improvmenet upon the intial torque beam idea for the C4 which didn't work all too well)
Just curious what you saw when stressing the rear kickup area. I'm looking at a few things to stiffen up the frame I'm working on, and wanted some additional information. Is the curved kickup area flexing (trying to straighten out), or is the transverse crossmember that the kickup attaches to (where the trailing arm front pivots are) twisting or rotating? I'm trying to put in some additional braces, and am trying to see what to concentrate on.
thanks,
Mike
04-13-2007, 07:06 PM
#205
The point where the kickup area is welded on top of the ladder frame, that's where it flexes. Expecially bad because you only have 3 full walls here w/ the trailing arm pocket. That's why I welded in those diagonal tubes to give it some more strength there. There really is no room for a gusset there.. see red arrows
