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Old 02-16-2012, 08:06 PM   #28 (permalink)
mort
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Quote:
Originally Posted by Diesel_Dave View Post
...
40 deg F change results in about a 20% change in mileage. So mileage changes 1% for every 2 deg change. That's pretty significant.
Or like you said 1% per Deg C.
Andd Superturnier's graph,
and PaleMelanesian's graph, which looks a little less steep. Great work!
Although all these seem to be for what I consider short commutes. 10 miles and 14 km. My commute is closer to 20 mi, but my graph would look similar, if...



My question is why? Does anybody vote for higher aero-drag because of denser air? It's a pretty big change, about 15% denser from 40 C to 0 C.
Or do the tires lose pressure, (same density issue)? Or does the engine lose efficiency just from having to start with colder intake air? That's also a surprisingly large effect. Lubricants are stiffer? Some kind of engine warm-up that burns fuel? Is there anything, besides moving, that helps?

-mort
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