We study non-hyperbolic repellers of diffeomorphisms derived from
transitive Anosov diffeomorphisms with unstable dimension 2
through a Hopf bifurcation. Using some recent abstract results
about non-uniformly expanding maps with holes, by ourselves and by
Dysman, we show that the Hausdorff dimension and the limit capacity
(box dimension) of the repeller are strictly less than the
dimension of the ambient manifold.