I live in Phoenix. Last year I trimmed a couple of inches from the lower cowl trailing edge to open the air exit and increase air flow. It made some improvement in temps, but not as much as I needed. This year I cut a 4” diameter circular hole in front of the cooler. The top edge of the hole is about 3/4” below the original cowling air intake opening. One flight so far at 90F OAT at takeoff. It still runs hot during climb out, but at least I was able to make a continuous climb to 6500 MSL (5500 AGL) without hitting 250F oil temp. After a few more flights I’ll be able to better judge the effectiveness, and I’ll post again.