Sr20det Operational Tempertures

[scca_civic]

I got an S13 w/ the SR20DET... I have the factory temp hooked up and when warmed up or running hard, it stays in the middle of the range, doesn't differ very much. However, I installed an aftermarket sensor on the pipe where my thermostat is attached. It runs around 180-195 degrees on a very easy run, but will climb all the way up to 220's when horsing around. Could where I mounted it play a big factor in the temperature change - because it can literally be at 180 degrees and I can accelerate really hard and it will run up to 210 degrees in about 30 seconds, but it will also cool down that fast as well. But on a 90 or so degree day - at 70 mph - just crusing - it is right around the 215-220 mark, but the factory gauge doesn't reflect a change at all??? any ideas?

I have a large alum radiator and two 12" fans that pull 3200 cfm each...