Fuel economy worse in cold temperatures

[bullwinkle]

Originally Posted by Skippy722
Originally Posted by Imp4
Originally Posted by borgward
You can turn on your air conditioner. That helps warm up the engine. The AC is now acting as a heat pump. It is taking heat out of the passenger compartment, releasing it through the condenser coil and passing it the the engines radiator. Once you begin to feel some heat turn off the AC. It works.

Dear lord, only a masochist or a BITOG true believer would turn on the a/c in winter to heat the engine up faster.
Now I truly have heard it all...

Not to mention that you can dump all the heat you want into the radiator, it's not getting to the engine till the thermostat opens

Strangely enough, it does work somewhat on the GMC Sierra 6.2 in my sig, with add-on air-the A/C compressor increases the load slightly, and the heat from the condenser does warm the radiator a little. But, I just put on the mittens/gloves & hat & go before it warms up fully anyway, diesel is too expensive to waste!

 

[spk2000]

Originally Posted by borgward
You can turn on your air conditioner. That helps warm up the engine. The AC is now acting as a heat pump. It is taking heat out of the passenger compartment, releasing it through the condenser coil and passing it the the engines radiator. Once you begin to feel some heat turn off the AC. It works.

I had a car that had an add on AC unit under the dash. Because it was not installed at the factory I could turn on the heat and AC at the same time causing the engine to heat up rapidly.

Small efficient engines tend to warm up slower than big engines. There are just less BTU's to transfer into the cooling system.



Interesting that I have the opposite. My smaller engines always run higher rpm's and hence heat up much faster than my big V8 Grand Marquis. At lower rpms the car is slow to heat up.

 

[fdcg27]

First off, unless you actually calculate fuel economy on each tank and log it, you have no idea what sort of mileage you're actually getting.
The display indicated fuel economy for the car is unlikely to be real and can be either optimistic, as is always the case with either of our Foresters, or pessimistic, which is always the case with our HAH.
You can expect a fuel economy hit of around 20% average over the winter with any car.
Between higher RVP fuel, longer time to engine reaching operating temperature as well as denser air, the reduction is expected and real.
With our HAH, I saw an average of 43.6 MPG over the first 10K beginning in October 2018. Over its next 10K, beginning April 2019, it averaged 53.3 mpg.
Fuel economy overall for the first 20K plus a few hundred was 47.9 mpg, in line with the EPA number of 47.
So, a fuel economy hit of nearly 20% cold to warm.
Happens with every machine, unfortunately.
Good part is that fuel is usually cheaper over the winter months since the allowed higher RVP blend is cheaper to make and demand is lower.
We have a station near our house that was at $1.949 Friday 1/31/20 but it turns out that I got screwed because it's now down to 1.869.

 

[D1dad]

My nissans get maybe 1mpg less on winter fuel. My impala with a 3.9 averages about 5 less which is a big deal on a car that get 28 in the summer

 

[geeman789]

Originally Posted by Lolvoguy
Originally Posted by 2010Civic

They don't look underinflated at all to me... The sidewall on the top and bottom of the tire looks equal.

The fronts look especially underinflated.


You sound like the guy who pumps his tires up to 50 psi, just because ...

The pictures tell you nothing. Radial tires bulge a little anyways, even at the correct psi.

 

[Pete44]

Originally Posted by fdcg27
First off, unless you actually calculate fuel economy on each tank and log it, you have no idea what sort of mileage you're actually getting.
The display indicated fuel economy for the car is unlikely to be real and can be either optimistic, as is always the case with either of our Foresters, or pessimistic, which is always the case with our HAH.
You can expect a fuel economy hit of around 20% average over the winter with any car.
Between higher RVP fuel, longer time to engine reaching operating temperature as well as denser air, the reduction is expected and real.
With our HAH, I saw an average of 43.6 MPG over the first 10K beginning in October 2018. Over its next 10K, beginning April 2019, it averaged 53.3 mpg.
Fuel economy overall for the first 20K plus a few hundred was 47.9 mpg, in line with the EPA number of 47.
So, a fuel economy hit of nearly 20% cold to warm.
Happens with every machine, unfortunately.
Good part is that fuel is usually cheaper over the winter months since the allowed higher RVP blend is cheaper to make and demand is lower.
We have a station near our house that was at $1.949 Friday 1/31/20 but it turns out that I got screwed because it's now down to 1.869.


I think you got screwed because someone got you to buy so many vehicles!!

 

[Lubener]

Longer warm up times and drivers letting their engines idle needlessly to warm up in the driveway all contribute to much lower MPG. All engines have lower MPG in the colder months.

 

[gj]

I've been thinking that maybe the computer that figures Miles per gallon hates the cold .
Or as someone pointed out most all cars MPGs aren't as good in winter .
Since I've never owned a car that calculated that sort of thing it's probably been going on under my nose since I started driving in 1978 .
Thanks .

 

[gj]

I used to be able to walk to work . My house burned down so now I have to drive about 10 miles one way . I have to be at work @ 3:30 pm so a lot of the time it's 2:45pm . % 99 I
start car , press brake , place in drive with foot still on brake . Try not to use or use as little accelerator as possible untill i think everything's got circulated .
My dad caught me revving the engine on my first car ,a 1975 Plymouth Duster 318 one cold morning . He let me know that wasn't a very smart thing to do .
Thanks .

 

[gj]

I used to be able to walk to work . My house burned down so now I have to drive about 10 miles one way . I have to be at work @ 3:30 pm so a lot of the time it's 2:45pm . % 99 I
start car , press brake , place in drive with foot still on brake . Try not to use or use as little accelerator as possible untill i think everything's got circulated .
My dad caught me revving the engine on my first car ,a 1975 Plymouth Duster 318 one cold morning . He let me know that wasn't a very smart thing to do .
Thanks .

 

[R18Civic]

Normal, I see a 2-3mpg drop in cold weather.