Where is the temp sensor located? Aftermarket gauge?
On the oil filter relocator block? into, or out of, the cooler?
Have you touched the oil cooler when it's reached 130 degrees to ensure there is flow going to the cooler?
If your water temps are still 84 i reckon it's a dodgy gauge or sender. Generally water and oil temps rise and fall at the same rates... when I was at the track on a 35 deg day, my water temps got to ~100 and oil around ~130 with a cooler.
If you can get your hands on one of them laser temp guns (point laser at item, it tells you how hot it is), after a run and the car is showing oil temps greater than 100, fire the laser at the inlet pipe end of the cooler and see what it reads...
don't know if that helps