IAT Readings "Hot" Normal???
no fans running below about 220F, meaning your engine
bay is cooking big time, heating the wall of the resonator
or lid or wherever your IAT resides and pulling out timing
when it gets hot.
Decent cold air setup and relocating the IAT sure do help.
"Free Ram Air" likely makes it worse except at high steady
road speed.
Do some quick checks to make sure the IAT sensor hasn't gone bad. Without starting the engine, scan the IAT and ECT temps after the car's been sitting all night. They should both be very close together and at ambient.
Are your fans tuned to run cooler? Have a 160 stat? Those help a ton in hot weather. Is your sensor in the stock location or has it been moved? Like jimmy says, if you have "free ram air", try blocking it off and see if that helps.
On my C5, Ive relocated the sensor right at the top of the plastic intake of the Vararam, and adjusted my IAT tables with HP Tuners






