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Old 10-02-2009, 05:50 PM   #85 (permalink)
Jammer
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Location: East Kentucky
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Quote:
Originally Posted by Nevyn View Post
What kind of mileage are you XFE guys seeing on a cold engine? I just took one for a spin and was impressed AND disapointed. 54 degrees F outside; completely cold car, 7.4 miles, 34.7 MPG. Good, but I was hoping for 37 from cold. Was I too "gentle" in my hypermiling, or is that a decent return?

I have two cars that are both dying; I fear one will keel over this winter for good. So I'm weighing options.
Tire Pressure / Battery

(My first thought is it may be your gas- see next paragraph)

It has dropped down to 40 degrees here during some of my short test runs trying to improve my driving in EOC. I'm still holding steady at 45.4MPG- However I noticed my tire pressure dropped when it got cold and that can explain some lost MPG. I now try to keep my tires at 40PPSI - they hold 44 MAX, so I figure 40 would give me some head way during warmer days and longer drives in which the tire pressure goes up. GM claims 30ppsi for the tires, but raising it sure does help the mileage and the outside temps directly impact the tires and the battery in the trunk. My problem is I have too much power drain running with brights on, along with all of my car's toys like cb radio, radar detector and GPS and even MORE- thus driving half as much in EOC is creating a situation in which my battery is cold and not holding a charge like a warm battery would in an engine compartment running full time. I plan on taking some advise on here and duct tape some home insulation on the bottom and sides of my battery.

Gasoline:

They mix gasoline ahead of the dates it gets pumped into cars and they try to formulate gas so it will burn it's best at the EXPECTED TEMPERATURES FOR THE TIME OF YEAR YOU FILL UP. Sometimes they screw up, and a summer may be fairly cool and the gas is mixed for hot temps which results in poor MPG. The same applies in reverse, if it is getting colder much earlier in the year than average your gasoline may be formulated to burn it's best at a higher temp. (I am basing this information on what many people have told me for years, but if anyone else has information on this stuff please share it here.)
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