Ma-Motorsports Boosted performance turbo build

BGTV8

Inlet Air Temperature - higher the IAT, the less dense the air entering the engine and if not compensated for by reducing fueling, the engine runs rich which reduces power.

Even if the ECU fuel/IAT map reduces fuel (to reduce emissions from unburnt fuel), it will kill power generated.

So, high IAT is "not good" for max power.

Lower IAT will give you more grunt - thats why early in a cool spring morning, your car "runs better".

FI compresses the inlet charge and that heats it up, so therefore you need to run an intercooler to reduce IAT, but in high ambient temps about the best you can hope for is reducing IAT's to a few degrees above ambient.

Hope that explains it