I have seen this trouble as well, but in a different manner
The NA fans has a fixed velocity while the turbo ones uses low and high, somewhat our NA speed is not enough in some cases.
I have my car with opened hood vents, blitz 1.3 kg cap, coolant/water mix 50%/50% and the NA fans are working in pararell.
It is alwasy great, I can do dyno pulls, drag, traffic, cruising with no problems, but If I turn on the A/C on very hot days on traffic, I will overheat 10-12 deg over the standard mnax reading, that`s around 108-110 Deg Celcious top.
I am thinking on putting 100% water to the engine, I also put the turbo radiator core with the NA tanks, (thicker)
I know the fans speed are the culprit, but can`t have th eturbo fans installed in the rad upper and lower tank of the na style, they simply don`t fit