APR chip owners...have you notice better MPG when weather climbs over 45F?
02-19-2009, 06:43 AM
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APR chip owners...have you notice better MPG when weather climbs over 45F?
I've noticed something strange and consistent lately. I seem to get almost 2 mpg better mileage when the outside temp climbs over ~45F. It's like an on off switch...lower temps, I lose 2 mpg, and higher temps I gain it back. Same commute, basically the same mix of city/highway driving, the only significant difference is weather it's over 45 degrees or not.
I don't think I'm losing my mind.......?
I don't think I'm losing my mind.......?
02-19-2009, 06:53 AM
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Haven't noticed
Will have to check my fuel log book for MPG and just compare winter to summer.
FWIW, I find myself having a little more fun when it gets colder. The decrease in air temperature works great with the turbo. It's really fun when it gets below 0F.
FWIW, I find myself having a little more fun when it gets colder. The decrease in air temperature works great with the turbo. It's really fun when it gets below 0F.
02-19-2009, 07:27 AM
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Nope...temps are bouncing around lately...
Last week we had 1-2 nice days, then temps dropped. Then today it's back over 45. mpg's followed the weather. Filling up at the same station lately.
02-19-2009, 09:11 AM
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you'll need to accept darknd4's answer as a factor (a large one). it IS part of the issue...
and fyi, an engine is more efficient when the difference between outside air temp and engine temp is at its greatest.
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02-19-2009, 01:53 PM
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Even stock gas mileage is poor in colder temps
I suspect it has something to do with colder air = denser air = more fuel burnt.
That and more fuel being burned on startup to get the catalytic converter warmed up faster.
That and more fuel being burned on startup to get the catalytic converter warmed up faster.
02-19-2009, 02:00 PM
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I understand how fuel mixes can alter mpg, but in this situation, it's not a factor.
They haven't changed over to the summer fuels yet. What I'm seeing is not a proportional change based on ambient temperatures. Instead I'm seeing a drastic change around 45 degrees. Above or below a very narrow temperature band, the fuel economy is consistent, but across that narrow band around 45 degrees, it's not. If I graphed it, you'd see a very clear S shaped curve with a steep rise near 45 degrees.
02-19-2009, 02:03 PM
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see my response to lowdef below...
If I observed something directly proportional to ambient temps, I would suspect this was the cause. But it's as if the car behaves differently above 45. I'd even go so far as the say the engine seems much smoother too, but that could very well be my mind playing tricks on me, so I won't go there.