Nothing known to mankind has higher latent heat than pure water. Water also expands 1600 times in volume when turning to steam at atmospheric pressure. To turn water into steam at 8 psi, it requires a greater temperature than 212F to ensure some level of equal distribution. If the manifold is designed for dry flow, equal distribution is a real challenge.
If that was still the objective, you have to maintain temp above boiling at the boost pressure, while the temp drops during injection. So . . .
At 10psi boost, you need +240F constant, plus the mass flow to maintain that.
That means inlet temps should be +130F WITH enough mass flow for the injected volume make the equation work.