New Aluminum radiator and temp gauge indications

I recently installed a new aluminum radiator from Wizard Cooling when I upgraded my AC system earlier this year as well as a new aluminum AC condenser. I used 2- 10" Spal fans and fully shrouded the radiator. I was very careful to construct the shroud so that no air can leak out.
I should have taken more photos

A couple of notes. My car is a turbo car and I log all the data and events in the Motec ECU. I also keep the laptop with me when I make test drives for a quick reference as to what's happening.

The car never overheated with the original radiator. The temperature gauge never indicated more than 100c. even in traffic. Turn on the headlights and the temperature gauge would move up a few needle widths. The gauges in these cars are not protected from voltage loads against the alternator which influences their accuracy (ie. makes the gauge read higher with more electrical demand). I also connected the unused light in the instrument cluster to indicate when the radiator fan comes on (water temp 90c). This is a much more reliable indication of the water temp than the gauge!

Test day is 107F or 42c. It was a warm day here.

The results- My temp gauge indicates Hotter!! I would estimate it at 100c. Just under the 3/4 mark on the Euro gauge. 115c or fully 3/4 with the head lights on. The high temps fans are not on. The light on my instrument panel is not on.

When I look over at the PC it disagrees with the gauge. No shock to me. The ECU shows a steady 82c. After some time in stop and go traffic I did get it up to 85c when I reviewed the data logs. The high temp fan never came on. Only the AC condenser fan was running. My high temp fans come on at 90c.
I was running the AC it was 107!

Very preliminary conclusion after a few drives- I think the temp gauge reads higher because I was using the AC. Just like turning on your headlights or any other electrical load. It was way to hot to test without the AC! I will test more when it cools off.

From a data perspective. The aluminum radiator performed very well. Highest temp reached was 85c. A single AC condenser fan was sufficient to keep everything cool. I will have to test further to see if ever needs to run both fans at the same time.

The aluminum radiator and shroud is a bit of trouble construct and is a very tight fit. But well worth the money and effort especially if your is leaking. I don't like leaks!!

Final thought- Your engine probably isn't as hot as your gauge is telling you. Its hard to ignore when its right in front of you. Try the light trick for piece of mind, when it does come on you can have some method to calibrate your temp gauge.
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Thanks for the tip Gordon. I will investigate. Why didn't you tell me this when I literally had the whole car apart ?
I had contemplated replacing the battery to starter cable and ground to frame with larger conductor cables.