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Originally Posted by Christ

I have to mention that if your engine is functioning, and not malfunctioning, you're not depriving it of airflow. Keep in mind that most engines are already running air deficient compared to their max VE. By using hotter air, you're only allowing a higher throttle opening without making unnecessary power, reducing pumping losses. You're not putting your engine in danger at all, other than from detonation, and if your engine didn't like the warmer air, you'd be getting worse mileage as it dumped fuel to keep detonation at bay, or retarded the timing for the same reason.

christ. have you ever tried/had to attempt to fix or even seen the internals of an engine that expired from detonation? google up some images
from street engines. then look at racing. high boost turbos, AA blowers, nitrous coming on without the additional fuel needed appropriately responding.
have you ever seen sparkplugs that look as if they had been made by alcoa?

"You're not putting your engine in danger at all, other than from detonation, and if your engine didn't like the warmer air, you'd be getting worse mileage as it dumped fuel to keep detonation at bay, or retarded the timing for the same reason."

you are obviously talking about an FE engine.
modern FE engines are equipped with dual band knock sensors which will knock back timing (i cant believe i said that do that long enough and your
exhaust manifolds will begin to glow and with the *concept* of wanting to flow preheated air through them there is even less capacity for cooling.
if that/those manifolds are made of aluminun they will be at risk of melting. now imagine having a dummy car with only a carburetor and mechanical distributor and no way to sense less than ideal combustion and the only way for you to find out through the coolant gauge, steam emitting from the hood.

there are ppl on here that dont know how to bump-start a coasting car
and they are being counseled to draw their intake air out from under the
exhaust manifold shield? UMBFK!

None of the reasons in your post, although they were posted with conviction, as it appears, weren't "the whole story" as it were.

the story from my contingent is complete.
now i would like to hear yours.
please dont repeat: "higher throttle opening without making unnecessary power, reducing pumping losses" as i have read it many times. it is a simple
concept, not difficult to understand- thin air is favored when flowing around
objects, tight radii, sharp valves and seats, throttle plates and even carburetor internals found in older vehicles.
the concept i cannot warm up to no matter how hard i try,
is how an engine that is ingesting fewer air molecules can produce more power per cycle than the same engine being fed more.

ots of cars could benefit from a smaller engine with a turbo, because you're not really efficient at low throttle angles, and an engine that's small enough to be truly efficient at cruise conditions isn't going to be able to accelerate quickly enough to really be effective in the real world.
Add a turbo and a bit more fuel with detonation deterrents to that smaller "efficient cruise" engine, and you've got a great combo.

Hm. I didn't go to engineering school, and automakers still haven't really figured this out.

"an engine that's small enough to be truly efficient at cruise conditions isn't going to be able to accelerate quickly enough to really be effective in the real world"

sequential turbocharging, electrically assisted turbos, variable valves, momentary ultra lean burn, and most recently VWs upercharger/turbocharger technology have most been implemented in OE situations, as well as availability for the aftermarket
(except for VWs s/t technology)
once again i would encourage anyone with the means to visit Europe.