  Ideal hydrodynamic simulations are performed to compute the evolution with
collision energy of hadron spectra and elliptic flow between AGS and LHC
energies. We argue that viscous effects should decrease with increasing energy,
improving the applicability of ideal fluid dynamics at higher energies. We show
that the increasing radial flow at higher energies pushes the elliptic flow to
larger transverse momenta, leading to a peaking and subsequent decrease of the
elliptic flow at fixed p_T with increasing collision energy, independent of
whether or not there is a phase transition in the equation of state.
