Intake manifold has asbestos gasket to insulate heat ( from cylinder
head ), but the 9 nuts which lock manifold onto cylinder head have
no asbestos washer, so heat enters manifold via [i] these 9 nuts  [ii]
the exhaust gas channeled to EGR valve  [iii] * channeled through
manifold .[iv] manifold chamber via EAC & Fast Idle valves.
www.autozone.com/images/cds/gif/large/0900823d800cf4a6.gif
Designer seemingly assumed [i] ambient air is never >20ºC ( can
be seen from exhaust manifold's front & rear covers
www.hondaautomotiveparts.com/auto/jsp/mws/catimgs/13sm40_d08.gif
- meant to keep exhaust gas hot, unnecessary & bad in warmer
climate ), & [ii] users will use * to heat their seats' spaces, so *
will not be >40ºC.
To further cool air intake, I use polystyrene & rubber washers to
insulate chamber from these 2 valves, glued 3 heatsinks onto
chamber, fitted copper wires & hoses ( with water & surfactant )
onto chamber & throttle body.  Then air intake is cooler : warm-
starts & hill climbing are easier, in even 27ºC ambient air, let
alone in hotter weather.
These 2 valves' insulations also make Fast Idle valve heat up &
reduce idling rpm sooner, & save petrol during idling / coasting.
I could not post here a photo of my F20A's chamber & valves,
looks like this NG bans any photo.