  We report on recent results from VISH2+1, a code that solves the relativistic
Israel-Stewart equations for causal viscous hydrodynamics for heavy-ion
collisions with longitudinal boost invariance. We find that even ``minimal''
shear viscosity eta/s=hbar/(4pi) leads to a large reduction of elliptic flow
compared to ideal fluid dynamics. We explore systematically the sensitivity of
this reduction to the equation of state, system size, initial conditions, and
the microscopic relaxation time in different formulations of the Israel-Stewart
equations.
