mpg
#7
JK Super Freak
Motors run a much richer mixture when they're warming up, & if it's really cold out they take longer to warm up as well, all the time running rich. So if you do a lot of short trips in winter then you will use a lot more gas for the same amount of miles travelled then if you are doing long freeway trips, where the motor is fully warmed up & running a leaner mixture for the majority of the miles travelled.
With old-school carburetted motors with contact, vacuum-advanced distributor ignition systems you would sometimes literally see a doubling of fuel use running a motor for only short trips in winter (particularly if the carby had a manual choke that you left out longer than needed); modern multipoint and direct electronic fuel-injected motors with computer controlled coil-pack ignition are far more efficient with their fuel metering and timing settings during cold start-up however you will still get considerably fewer miles per tank running this way (short distance winter-weather trips).
With old-school carburetted motors with contact, vacuum-advanced distributor ignition systems you would sometimes literally see a doubling of fuel use running a motor for only short trips in winter (particularly if the carby had a manual choke that you left out longer than needed); modern multipoint and direct electronic fuel-injected motors with computer controlled coil-pack ignition are far more efficient with their fuel metering and timing settings during cold start-up however you will still get considerably fewer miles per tank running this way (short distance winter-weather trips).
Last edited by JKlad; 12-08-2011 at 02:07 AM.
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#8
JK Junkie
I noticed my mpg dropped from 19mpg to 17.8 myself. It is the winter blends of fuel that is being used.
Also, when it is colder... engines do run richer to warm up to operating temps. When I start up to go to work, I lose like .4 mpg on the first 5 miles no matter how easy I drive it. Then it climbs back up again.
Also, when it is colder... engines do run richer to warm up to operating temps. When I start up to go to work, I lose like .4 mpg on the first 5 miles no matter how easy I drive it. Then it climbs back up again.
#9
Originally Posted by IcyFridge
I noticed my mpg dropped from 19mpg to 17.8 myself. It is the winter blends of fuel that is being used.
Also, when it is colder... engines do run richer to warm up to operating temps. When I start up to go to work, I lose like .4 mpg on the first 5 miles no matter how easy I drive it. Then it climbs back up again.
Also, when it is colder... engines do run richer to warm up to operating temps. When I start up to go to work, I lose like .4 mpg on the first 5 miles no matter how easy I drive it. Then it climbs back up again.
I'm summary ^ ( winter sucks ! )