I had done some good before and after measurements when installing the Jackson dual radiator water to oil cooler. My finding ls were as follows:
-with regular 0-20 oil, driving at high rpm (say at 4000rpm or above) on the highway for 20mins or more can really crank out temps to 250F and up to 280F. I found its more a factor of rpm rather than speed.
-my recommendation would be for anyone NA Or FI that likes to drive at high rpm for extended periods to at Least go to a quality 5-40 oil. i would strongly recommend an oil cooler for Someone driving extensively at 5000rpm or more, such as on track.
-for my case, the dual jackson rad/oil cooler was very effective for an all year round solution , and kept temps below 240F (with 5-40 oil) even in high demand situations , while helping warming oil up in the winter time as well.
Link to my measurements with and without cooler with high rpm (low speed) driving on the highway:
https://www.ft86club.com/forums/show...104943&page=24