92JDMSiR

ok, it was kinda hot today here in jersey, around 85-90, but I think it gets hotter in cali so it doesn't matter. I was driving around town today for about 10 minutes then I got on the highway for about 15 minutes and all of a sudden the temp starts to climb??? WTF I was doin about 75 mph at 4100 rpm and the needle just started to poke it's head over halfway point. I turned on my A/C fan and brought the speed down a little so that I was doin about 3500 rpm's and the temp dropped back to normal. so I turn around on the highway and head back home still chillen this time around 3800 and it starts to rise again. bring her back down from ludicrous speed(yeah, right) to about 3500-3400 and she's back to normal. what the hell could this be????the setup is as follows.
b16, drag 3 kit with ITR tranny. I put a boost controller in on monday but I'm only boosting 6 psi. the boost controller shouldn't matter. the cooling system is bone stock. I do have the paper thin cx radiator but I don't want to get an aftermarket one because I hear they could be even worse. let me know what you think I need help with this. I don't want to drive like this

TurboSedan

Check your thermostat to make sure it is opening properly. Also make sure the water pump is working properly. Next, check to see if you have over-filled your radiator overflow tank. If so, your head gasket may be blown.

92JDMSiR

the overfill isn't overflowing but it was about 3/4 full. I replaced the water pump about 1000 miles ago, so i don't think that is it

TurboSedan

Thermostat then?