[Cherrier Vivace] Rear car bounce hard after bottom out

I swap front & rear suspension with rally independent suspension, both wheels with rally gravel coilover
Wherever i lower the spring rates almost to the bottom, the car just bounce harder.
tried 0 value in beamLimitSpring & beamLimitDamp on helper spring, hydraulic bump stop still nothing
what cause these?

 

if you're bottoming out the suspension, it'll just be sitting on the rubber bump stops, which themselves are quite stiff, and don't handle very well.

what are you trying to tune the car for?
if you want to do jumps with it or something, you'll want to raise the ride height as high as you can, but you'll still need pretty stiff springs and really stiff shocks, so they don't bottom out even with the whole weight of the car hitting the ground.
if you want to stance the car, you'll want the springs really stiff, so that they're taking all of the forces themselves in the tiny amount of space they're moving in.

 

the car mostly for jumping, i did stiffen up the spring and it does alleviate the issue. stiff shock didn't help the car due to increasing nosedive angle, but try balanced shock it work well.
lol i thought i could get away with soft spring and bottoming out but it didn't work that way...