Oil Flow in a Constricted Pipe

Oil with a specific gravity $SG=0\mathrm{.}9$ is pumped through the apparatus shown in Figure $2.$ The velocity at the upstream section is $v_{up}=1\mathrm{.}7m{s}^{-1}$ whereas the velocity in the downstream $($i$.$e$.,$ constricted$)$ section is $v_{\text{d}\text{o}\text{w}\text{n}}=7m{s}^{-1}.$ On the upstream side there is a piezometer whereas on the downstream side there is both a piezometer and a Pitot tube. Assuming viscous effects are negligible, find the height differences for $z_2$ and $z_3.$