[bobdbilder]

Its not about so much the temperature but more on the flow and vacuum reduction. Reducing vacuum in the intake means there is close to sufficient flow of air to meet the required air:fuel ratio. We know that the throttle is actually choking the engine if its not fully open. Every move of the flap of the throttle body causes eddies downstream which leads to flow losses. This flap moves constantly when you are driving/riding (because terrain is never flat) and is never steady even when you think your foot (or hand) is rock hard.

The secondary intake actually increases the size of the intake to reduce and cope with fluctuations in vacuum. If the TB's throat is 72mm dia, an intake port the size of 100mm dia will only help. This is especially true when you drive above 50km/h where there is sufficient pressure from outside air to reduce vacuum. You could say a flow of air that is always more than the engine needs. The location of the intake scoop is then important. Autospeed has that covered very well by mapping the aerodynamic pressure points throughout the front of the car.

I have changed the pipe from convoluted flexible accordian style washing machine hose to a smooth inner surface pipe is to increase the effective flow area. I also think that there is a venturi effect where the smaller pipe meets the main intake. The bigger flow from the main intake 'sucks' the air from the smaller diameter pipe.

Coming back to air temperature, higher values actually helps the atomization of fuel through the injectors. Its good for FE but not so much in getting high peak power; hotter air having less mass. So those billet aluminium fuel rail sold off as bling actually does help.