  We use the multiconfiguration Dirac-Hartree-Fock (MCDHF) method combined with
the relativistic configuration interaction (RCI) approach (GRASP2K) to provide
a consistent set of transition energies and radiative transition data for the
lower $n =3$ states in all Cl-like ions of astrophysical importance, from
\ion{Cr}{8} to \ion{Zn}{14}. We also provide excitation energies calculated for
\mbox{Fe X} using the many-body perturbation theory (MBPT, implemented within
FAC). The comparison of the present MCDHF results with MBPT and with the
available experimental energies indicates that the theoretical excitation
energies are highly accurate, with uncertainties of only a few hundred
cm$^{-1}$. Detailed comparisons for Fe~X and Ni~XII highlight discrepancies in
the experimental energies found in the literature. Several new identifications
are proposed.
