Quote:
and engineers can’t explain why a car that is torsionally soft is so fast in venues with curves. ... as Mjalaly said, to summarize: “There’s a lot of things wrong with the car but a few that are right. And those few that are right, overpower those that are wrong.”
If your camber curves and weight distribution are in a ball park you may not need a lot of rigidity. Lots of secondary issues though. Bobber for instance your worksheets on chassis forces won't work because there is no reason to think the front and rear of the car roll the same amount. So you can't redistribute the dynamic weight transfer from accelerating laterally or longitudinally.
Chassis flex will give difficulty mounting things to the chassis, even doors like Andrew mentions.
There may be chassis fatigue issues because the lack of stiffness is indicating bending loads on the tubes and they will stress at the nodes. This is especially bad if the chassis is stiff some places and flexible others. Tube frames should be checked for cracking at these nodes especially flexible frames.
When we did the torsional rigidity test on the Locost chassis, there was a tube in the engine bay that was subject to more than 5 times the stress I allowed for any tube on Car9, and the stiffness of the chassis was nearly an order of magnitude lower. A small difference in build procedure like how you attached the floor in that area or relocate the tube an inch or two would probably cause frame cracking.
I wonder if you see any issues with lack of shock absorber ability on those cars?