I'll say +1 for what ncjay said. If you're racing in a class that doesn't allow chassis bracing it could give a good advantage.
Normally though it's better to cage the car because even a fresh chassis will lose stiffness pretty quick in racing.
I'll say +1 for what ncjay said. If you're racing in a class that doesn't allow chassis bracing it could give a good advantage.
Normally though it's better to cage the car because even a fresh chassis will lose stiffness pretty quick in racing.
This thread sounds like i should go ahead and try to make this happen. 300k chassis has been crashed and is slightly bent. I have enough adjustment to get it to take an alignment, but it's definitely tweaked. Also has rust issues that are definitely repairable, but that and the bodywork/paint were the other positives i was already chalking up to the 10k chassis.
So i guess i have a phone call to make.
Do it, if the fresh chassis happens to be a 323 and you decide you don't need or want it I'll make sure it finds a home
It's not a 323, but i've pretty much given up on finding a 323 that wasn't in horrible shape.
Though it would be nice to lose that 200lbs by finding one.
Nathan JansenvanDoorn wrote: Work hardening does not change the modulus of elasticity for steel, and only happens when the material is plastically ("permanently") deformed. IE: doesn't apply to un-crashed chassis or (most) springs found in automobiles. You could certainly argue that the chassis gets floppier as the various joint loosen up,but I believe that typically chassis 'flex' is either a result of rust, or aged bushings and dampers. Just my .02. I would certainly swap chassis if rust was an issue, but would be much less likely if it was 'only' mileage.
This ^. The chassis is not going to work harden unless you bent it up somewhere and if you did you are probably going to have problems with geometry. Also, the modulus of elasticity doesn't apply if you are work hardening a material because you are in the plastic deformation zone and you can argue that it actually becomes less stiff.
So I guess it's really a question of how much you want to spend and how competitive you want to be.
Aren't rally cars i.e. Subarus seam welded for added stiffness?
Yes. Pro teams that race "stock" cars dip the chassis to clean everything off and then weld up all the seams.
could you stitch weld the 10k car for added rigidity? or is that against class rules?
In reply to ncjay:
I think the print mag had an article of a home built Subaru from VT who's driver was working his way up toward the pro ranks.
I believe he paint-stripped the chassis and seam welded it.
Dusterbd13 wrote: could you stitch weld the 10k car for added rigidity? or is that against class rules?
Against the rules.
Nathan JansenvanDoorn wrote: You could certainly argue that the chassis gets floppier as the various joint loosen up,but I believe that typically chassis 'flex' is either a result of rust, or aged bushings and dampers.
It's the metal weakening at the spot welds, really. Several million cycles of being stressed this way and that makes the steel more flexible around the welds. You can even see it sometimes on older chassis, the sheetmetal isn't flat at the welds anymore, but is visibly raised up where the welds aren't. Stretch and push and stretch and push, just a tiny bit each time.
This is what stitch welding aims to reduce. Not eliminate, since nothing will eliminate it, but it reduces it in the short term. (Long term... what is long term for a racing vehicle?)
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