Properties of superheated vapor R134a?

for English units, see this table

(click on SI once there for SI units if needed). If you need higher pressure than 400psia or 16MPa, you will need the R143a superheated vapor chart, which I can't find online. You can find tables and charts in various thermodynamics textbooks. For example, Tables in "fundamentals of engineering thermodynamics" by Moran and Shapiro; or the chart by "SUVA/DuPont" is in the appendix of the "mechanical engineering reference manual" by Lindeburg.