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Mini-experiment: cold start fuel consumption and warm-up time
Posted Wednesday, March 8/06 in Mods & Tests
Without trying too hard, you can probably think of a couple of reasons why it's better to drive a cold engine gently than to let a car sit idling to warm it up.
The obvious one is reduced fuel consumption. Another is lower emissions. And a big one is that driving the car actually gets everything up to operating temperature faster than just letting it sit running. (In fact, idling does nothing to warm the drivetrain, bearings, tires, etc.)
But how much faster? I didn't really know. Time to get some data!
This one's a really basic experiment: I timed how long my engine took to reach operating temperature (195 F) idling, from a cold start.
You're witnessing pure science here - I generally don't do cold starts since I installed my block heater, and even if I can't plug in, I never let the car sit idling.
(Have some fun here: before reading any further, take a guess how many minutes it took my car's 993cc powerhouse to reach operating temperature from a -7 C / 19 F start. Five minutes? Ten? More? Less? ...)
The test conditions:
- FWT: coolant (water) temp in degrees F
In an attempt to educate the public about the various costs of idling, a number of jurisdictions have implemented public awareness campaigns - and even laws restricting idle time.
- idlefree.ca - city of Vancouver, British Columbia
- Idle-Free zone - Natural Resources Canada
- In praise of the lowly block heater - MetroMPG.com
I heard from fellow Metro owner Mark with a related Alberta winter tale:
" Excellent new article about the warm-up time. I actually guessed 20 minutes, but I had a little more information to go on than you did:
-27 C: yikes! Fortunately, I think we're over the hump as far as this winter goes. Thanks, Mark!
darin AT metrompg D-O-T com, or here