Elliptical galaxies follow a well-known luminosity – metallicity (L − Z) relation, in the sense that more luminous ellipticals are observed to be more metal-rich than less luminous systems. Obviously this is a mass – Z relation, and its interpretation is that less massive galaxies had more significant outflows of metal-enriched gas at an early evolutionary stage. The apparent ellipticity (ϵ) had already been invoked to explain the large scatter in the L − Z relation, but Barazza & Binggeli (2002) observed that the relation between Z and ϵ in cluster dwarf elliptical galaxies (dEs) could even be stronger than the relation with mass. The idea is that outflow of metal-enriched gas preferentially occurs along the minor axis, making ϵ a critical parameter for Z in dwarfs. Here, we test this hypothesis using high-resolution N-body/SPH simulations including chemical feedback of dEs with different flattenings.