Attached is a simple Excel sheet that can be used to quickly evaluate the timestep calculated by LS-DYNA for solids, beams and shells.
It must be noted that for solid elements, Q is based on the C1 (default = 0.06) only.
For solid elements using MAT_SPOTWELD, LS-DYNA uses a slightly different method of computing the characteristic length. Rather than using the traditional method (ElementVolume/LargestSurfaceArea), MAT_SPOTWELD based solid elements use LargestArea/DiagonalLength. This is done to overcome a small timestep due to bad spotweld geometry.