So, how does the mister perform? Very well. I was (and still am) pleased to see just how effective the water spray can be.
For this testing I did runs in 3rd gear from 40 mph to 80 mph, hard on the brakes down to 40 mph then back to 80 mph. My intention was to heat soak the intercooler to see how it performed with a high heat load. I captured engine data via the diagnostic port. Before each run I drove at a steady 40-50 mph to get low, stable charge temperatures then I went full throttle in 3rd gear. Note that in 78°F weather there was a 27.8°F increase in temperature with no boost and the car moving.
Weather was 78°F with 72% relative humidity. Stock engine.
An interesting point to note is that on the 4th run to 80 mph at 4280 RPM the run with no misters had a charge temperature of 116°F (10.6°F above the start temp) while the run with misters and the same heat soak procedure at the same 4280 RPM had a charge temperature of 104°F (1.8°F below the start temp). The misters... they are effective!
I have a set of larger nozzles that I've yet to test. Given the results of my runs so far it looks like I might be able to get charge temperatures under full load that are below normal cruise temps. More on this later.
This data does not show intercooler recovery time. In daily use, my intercooler temperatures drop off very quickly after driving that trips the misters. Under conditions where temps would normally take 2-3 minutes of steady driving to recover (w/o misters) I see recovery times of 30-45 seconds. The quick recovery times are thanks to the misters continuing to run after I've already got off the throttle. Since the controller watches how you've been driving it knows when you've been running hard and therefore leaves the pump on for a short period after the boost event to help things cool off quickly. Very nice.