colder weather and air density
01-26-2007, 03:15 PM
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colder weather and air density
well, its ~15* here in beautiful upstate ny. as i was driving my srt4, i noticed today it was only boosting 10psi. i have an adjustable wga, set to 15psi.
i know colder air is more dense but is it enough for the stock ecu adjust accordingly? i was just wondering if anyone here knew the actual change in air density as air temperature changed, if humidity and barometric pressure were to remain constant.
also, i wonder how much leaner my honda would be running if i were to drive it now. if i could unbury it from the snow id give it a gander and then i could know the difference in AFR, but that probly wont happen for anytime soon. i just never thought that a seasonal change in air temperature can make the difference of 5 psi.
my gauge reads normal vacuum so im assuming my issue is not a leak. the car still feels just as strong too...
just wanted some opinions, hopefully some facts from some people more educated than myself.
i know colder air is more dense but is it enough for the stock ecu adjust accordingly? i was just wondering if anyone here knew the actual change in air density as air temperature changed, if humidity and barometric pressure were to remain constant.
also, i wonder how much leaner my honda would be running if i were to drive it now. if i could unbury it from the snow id give it a gander and then i could know the difference in AFR, but that probly wont happen for anytime soon. i just never thought that a seasonal change in air temperature can make the difference of 5 psi.
my gauge reads normal vacuum so im assuming my issue is not a leak. the car still feels just as strong too...
just wanted some opinions, hopefully some facts from some people more educated than myself.
01-26-2007, 07:47 PM
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Re: colder weather and air density (Finger Lickin' good)
ive personally seen a difference of .5-.7 afr from about 80*f to around 40*f, with the 40 degrees being leaner.
normally though you would boost more in cold air. this is a longshot, but maybe your knock sensor is seeing knock, pulling timing, flowing less air and making less boost. again probably not the case but it almost makes sense on the surface....
normally though you would boost more in cold air. this is a longshot, but maybe your knock sensor is seeing knock, pulling timing, flowing less air and making less boost. again probably not the case but it almost makes sense on the surface....
01-26-2007, 07:57 PM
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Re: colder weather and air density (bch5428)
Im not incredibly fermiliar with these cars. I would be leaning towards something electrical as blackeg has stated.
unless they're pulling the feed for the wastegate from somewhere infront of the intercooler in which case you might just be seeing a huge pressure drop accross the intercooler do to the added efficiency from the cooler ambient air temps.
Ive seen this large in deisels, since boost is proportional to fuel, on hot days when the air is dense I've seen 34psi where on a cold day in winter closer to 23psi. ('03 dodge 2500 with edge power programmer.)
unless they're pulling the feed for the wastegate from somewhere infront of the intercooler in which case you might just be seeing a huge pressure drop accross the intercooler do to the added efficiency from the cooler ambient air temps.
Ive seen this large in deisels, since boost is proportional to fuel, on hot days when the air is dense I've seen 34psi where on a cold day in winter closer to 23psi. ('03 dodge 2500 with edge power programmer.)
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