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Old 07-26-2008, 05:39 PM   #85 (permalink)
jamesqf
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Quote:
Originally Posted by Bror Jace View Post
Repeating my request from a page or more ago, has anyone measured (gallons per hour OK) fuel consumption rates with a scangauge at 55mph vs 65mph?
Not with a ScanGauge - I've found the fuel consumption measurement is not really accurate on mine - but with the built-in real-time mpg meter in my Insight.

As best I can tell, there is no simple 1:1 relationship between speed and mpg. There are times & places where I can be going 65 and getting 120-150 mpg, other times I can be going 55 and getting 55 mpg - both on fairly level roads without much head or tail wind. There are places - I680 through Sunol (SF Bay Area) for one - where going 65-75 gives better mileage than 55, because I can stay in 5th over the hills instead of dropping to 3rd. And of course there are all the long downhill runs where I use no gas at all, regardless of the speed I travel. (I have a picture somewhere of my trip gauge showing 150 mpg for a 70 mile trip - the trick is to start at 8500 ft, and finish near sea level :-))

All this is just one of the many reasons I don't like the idea of a mandatory 55 mph limit. It's a too-simplistic, one size fits all attempt at a solution.
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