<VV> Fuel milage and the cold

[Dale Dewald]

At 07:11 2/19/2010 -0500, Randy(cap'n) Hook wrote:

>Does colder temperatures give you worse or less gas mileage?? I have to 
>drive my '63 84/pg year-round and have noticed my mileage drop from 21/22 
>on average to 17/18.? Comments?? Physics reasons?? Thanks

As others have pointed out, the drop in fuel mileage in winter is caused by 
several factors.  I have also noticed the same drop with my Cummins 
diesel-powered Dodge truck.  It takes a longer time to get the engine up to 
operating temperature (especially to heat 10 qts of oil and 6 gal of 
coolant) and overcome the extra friction of cold gear lube, etc.  There is 
also a cold compensator on the injection pump that adjusts timing to help 
quicken warm-up which uses a bit more fuel.  Of course this is worse when 
driving short trips. In this case of a turbocharged engine the increased 
density of cold air is really not a factor.

On long trips I do notice an effect from fuel; winter blend diesel (usually 
50/50 #1 and #2) has less BTU per gallon than straight #2 diesel.

What really kills my winter mileage is locking the front axle hubs to run 
in 4WD, hanging a 800lb snow plow on the front, putting 600lbs of sand bags 
in the bed, and driving back and forth across parking lots pushing around 
all of this white stuff...

Then at 12:00 2/19/2010 -0500, Randy (Cap'n) Hook wrote:
>As an  amendment to my original question about fuel mileage in winter: for
>a Corvair,  what sort of difference does it make whether or not one opens
>and uses the  winter/summer opening in the lower shroud.  The '65 owners
>manual says to  open the slot at 60* F and lower temps.  Thoughts?

I understand that this slot provides some warm air recirculation to prevent 
carburetor icing.  I am not sure if it has any significant effect on 
warm-up time or fuel economy.

Dale Dewald
Hancock, MI