The test results are in and they are good!!
MX-5 and I ran some unscientific temperature tests yesterday while taking a country cruise with his PT group. On the Higway trip over to the park, the outside temp was 75. The ambient temp at the wheel well was approximately 73.5 and the throttle body was at 76 degrees. The insulation kept the temp down to a 2-3 degree temperature increase. On the road test the outside temp was still 75 degrees. The wheel well temp was measured at 74 and the throttle body was between78 and 80, a 4-6 temp increase. We did not have an opportunity to do a control test, but I will reference MX-5's previous temp tests for comparison.
http://www.ptdoityourself.net/ptairstudy.html
Enjoy!!
Dan