well I have an M2 nozzle pre-twins, another M2 pre-throttle on the greddy elbow running with a 250psi pump and a fast reacting AIT sensor in the stock location.

while boosting the AIT won't read the water injection change in temps but when I let off and go into vaccum after an injection event the temps go down fast! can't explain why... maybe the airflow is too fast to allow the water to cool the charge before the combustion chamber.

 

When you go into vacuum, water carried in the intake charge will readily vaporize due to the low manifold pressure and consequently reduce your IAT.

 

What if you're running mostly methanol ? That would change IAT quite a bit right?

 

As a follow up I've been running one M5 injector in the nozzle location Howard suggested for 2 seasons now. I stuck with the stock temp sensor location and changed to the fast acting AIT sensor. I have not noticed any detrimental effects to the sensor from it being sprayed with water at all.

neit_jnf I've done runs with the W/I turned off and under full throttle my AIT's climb then go back down when back in vacuum. With the W/I on they will either stay steady or climb maybe 2-5 degrees if it's very hot out, then similar to you I see a drop when off throttle. I always assumed that this was due to the stock twins just making that much heat when pushing 14psi like I am.