grill "shield" rather than block?

[lunarhighway]

I don't think getting the engine to suck in less dense air by feeding it HOT air is a good idea.

works pretty well for me. the entire idea of feeding hot air is that you restrict the actual oxygen delivered to the engine but not the ammount of air thus for a same ammount of power required more air will be needed to get the same ammount of oxygen
the throttle will be opened more and throttle related losses (flow restrictions) will be eliminated

a side effect is that the max power is reduced and the throttle will feel more spungey especially in summer.

my airbox has a build in wai with a valve that only opens during cold starts and witchs the standard intake to a schroud over the exhoust, by permanently forcig the valve partly open there's a always some warm air mixed with the airflow

in summer this notably improved economy at the cost of a few horses during the winter this setup does not compensates for the cold air and the engine is more powerfull again

my engine is only 71 Hp in a fairly large family car but due to the right gearing and good aero this is more than plenty

what i don't think is a good idea is to have a wai behind the radiator where the radiator acts as a flow restriction (unless the pickup was significantly large) because the whole point of wai is mainly to reduce pumping losses.