RayB said:
I understand the physics of why cooler air should result in more
complete/efficient/powerful combustion. The PCM comment, however, I think
holds the key to my question. If it doesn't make adjustments to match the
extremes, that would explain why, even though it's literally 100 degrees
colder (sometimes more like 120 degrees) during the 3rd week of January
than the 3rd week of July, it doesn't result in the linear response I'd
expect from the temperature difference.
Apparently, though, I just don't have a sensitive "seat of the pants" to
detect the improvements.
>
> Cooler intake air will make more horsepower, as well as better fuel
> mileage.
> That's why every auto manufacturer uses some sort of intake system that
> pulls in air from a location away from the highest heat source in the
> engine
> compartment. Cooler air creates more efficient combustion. However,
> there
> are limits to the effect cooler or hotter air will have. Below or above
> certain levels, there will be no noticeable difference. The PCM has
> limits
> on how far it will adjust to weather extremes. In a nutshell though,
> cooler air is better than hot air. In the 11 years I've been racing my
> truck, I've many times compared my factory 10x2.5 enclosed air cleaner
> with
> hoses to the grille area, to an open element, 14x3 K&N filter. The open
> element, sucking in engine heat, has always proven to slow me down by a
> tenth of a second and 1 mph at the track. That's equivalent to about a
> car
> length in the quarter mile.
>
> Actually, humidity and barometric pressure have a greater effect on
> performance than temperature alone. It just so happens that cooler
> weather
> is usually accompanied by lower humidity and higher pressure, thereby
> resulting in a noticeable performance increase.
>
> RayB
> http://www.dragtruk.com/ENTRIES/20KM1FD2KWBP.html
>
>
-- J Wynia Pragmapool, Inc. www.pragmapool.com
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