A friend of mine wired a multimeter to my temp sensor once and put a lighter under the sensor. It showed how slow it was to react to temp changes.
Guessing this is you mean EF Ian?
I did an experiment a while ago on air intake temperatures. I put a 0.5mm dia thermocouple in the hose exiting the intercooler and read the temperature. I also logged the nissan sensor. The thermocouple, being very small, could react very quickly to temperature change.
After a drive down the road it soon became apparent that both reading were identical and that the rate of temperature change is in fact not very fast.
It's worth noting that the volume of air passing the sensor, under full throttle/boost etc is large. This will make the sensor change temperature quicker than putting a lighter under it. Also, the temperature entering the engine is only a few degrees above ambient.
I also found out that with a 500hp engine, a HKS super sport intercooler only decreased the intake temperature by 1 degree over a standard intercooler.