How cold is too cold?
08-11-2005, 10:04 PM
#11
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To cold is the point at which icing occurs in the venturi area,and that's virtually unlimited in a modern fuel injected application probably aroud -20 degrees F.On older carburated designs a hot spot had to be added for cold weather usage because ice could form at tempertures above freezing.
08-11-2005, 10:36 PM
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Originally Posted by whitt1
To cold is the point at which icing occurs in the venturi area,and that's virtually unlimited in a modern fuel injected application probably aroud -20 degrees F.On older carburated designs a hot spot had to be added for cold weather usage because ice could form at tempertures above freezing.
-20F would be nice though wouldn't it. 
08-11-2005, 10:46 PM
#13
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i've found that much below around 40ºF there isn't much gain to be had in lower temps. at temps lower than that the fuel doesn't atomize as well in the intake as it would just before it shoots into the head. if these engines had a direct injection fuel system there would be some more gain in that. once you get to around 20ºF or so you end up with commonly very low humidity in the air as well as if i recall correctly a lower % of oxygen in the air.
08-11-2005, 10:59 PM
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Originally Posted by zippy
once you get to around 20ºF or so you end up with commonly very low humidity in the air as well as if i recall correctly a lower % of oxygen in the air.
08-11-2005, 11:22 PM
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where does the engine measure temperature of air coming in so as to adjust air/fuel mixture accordingly? if it is at the maf, then wouldnt you have to make the air cold BEFORE the maf?
08-11-2005, 11:28 PM
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Originally Posted by jerome
where does the engine measure temperature of air coming in so as to adjust air/fuel mixture accordingly? if it is at the maf, then wouldnt you have to make the air cold BEFORE the maf?
08-11-2005, 11:53 PM
#17
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Originally Posted by vanillagorilla
Why would there be a lower percent of O2? Percent by volume? How? It's denser.
i could be incorrect on that, but i'm trying to remember from my chemistry class where this discussion came up. it may be that there is less of that process going on of plants creating the oxygen in the cold. i honestly don't remember. i could be w***g on that one.
08-12-2005, 04:35 PM
#18
Originally Posted by 954RR
I am 99% sure that plants producing less oxygen in cold environments has to do with the stability of the CO2 molecule in very cold conditions and a plant not being as able to break it up to make O2 Also the half life of CO2 is less in cold conditions (first order-kt(ln[A]) where "t" is temp.
