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Author Topic: How much does winterr impact on fuel economy  (Read 647 times)

December 02, 2018, 09:48:59 pm

Dasked

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How much does winterr impact on fuel economy
« on: December 02, 2018, 09:48:59 pm »
Hello

  I know it really hurts gas engines, how about diesels?  Has anybody kept good enough records to notice a difference on their VW Diesel?



Reply #1December 03, 2018, 05:24:50 pm

libbydiesel

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Re: How much does winterr impact on fuel economy
« Reply #1 on: December 03, 2018, 05:24:50 pm »
The only time cold weather really affects the fuel economy of either gas or diesel engines is the time prior to coming to normal operating temperature.  If you idle a lot during warmup (terrible for you engine and terrible for the environment) then you will see lower fuel economy on either one due to burning fuel for no miles driven.  If you do a lot of short trips where most of the driving time is spent getting the engine up to normal operating temperature, you will also see a hit.  If you do mostly extended highway driving then the difference would be much less.  Finally winter formulation of diesel fuel results in worse fuel economy.

If you're actually looking for a set number that takes into account those factors, then get out your note pad and calculator and track it this year and you'll have a pretty good guess for next year provided your driving habits and your pump fuel formulations don't change.   
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Reply #2December 10, 2018, 06:48:42 pm

RunninWild

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Re: How much does winterr impact on fuel economy
« Reply #2 on: December 10, 2018, 06:48:42 pm »
ive kept my trip meter going since I bought my chevy cruze diesel a year ago. last winter I was averaging 5.7l/100km, the summer it dropped to 5.5l/100km with my average tank in the summer being mostly around 5.2l/100km. Not a huge difference but give or take 10%. I should also mention I don't warm my car up before I drive it. working some night shifts in the winter I would sit and idle to warm up so that is a factor as well. not for hours but 10-20min a few times over a tank of idle was usually enough to ruin a good tanks mpg
« Last Edit: December 10, 2018, 06:50:26 pm by RunninWild »

Reply #3December 10, 2018, 08:09:28 pm

ORCoaster

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Re: How much does winterr impact on fuel economy
« Reply #3 on: December 10, 2018, 08:09:28 pm »
You will see a dip in mileage during the winter.  Can't be helped.  Colder temps, different fuel mix and how you drive all play into it.  Stop and go instead of smooth light through light because the roads are snow covered or it is pouring rain and people just are being careful and slowing down.

Idling an engine to warm it up is just plain foolish.  A little bit of time to get the oil moving around to all the parts, a little extra sit at start up to get the injectors warmer is all that is needed.  You might be talking 2 mins at the most when the temps are in the teens and twenties.  The real killer is the cold fuel going to the injectors.  Some engines have preheaters in their fuel delivery systems to compensate for that.  Most early VW's do not.  Not sure about the newer ones. 

I generally see my in town mileage drop from 34 to 30 in the winter.  But my trips really don't get the engine very warm.  I do get heat in the car but the gauge says less than 180 by the time I get to work or back home.  That is still under the thermostat temp of 193 F. 

Looking to add fender trim, LED lights and a bumper push to the truck soon.

Reply #4December 15, 2018, 09:11:30 am

smutts

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Re: How much does winterr impact on fuel economy
« Reply #4 on: December 15, 2018, 09:11:30 am »
Looking over the last four years, 100,000 miles, 12,000 ish of ridiculously over taxed diesel. >:(
My winter mpg gets worse by about 2.5 mpg imperial. So about 2mpg US.

Mind you that is the south UK, which isn't particularly cold in winter. Snow? In the UK? Just give up, no one here has a clue.
Then again, there is this bloke in his bus, enjoy...https://www.youtube.com/watch?v=4Pcdg9m7Dao

Diesel here is 1.35 per litre, that would be $6.61 a US gallon.  :o
Now where did I put my yellow florescent waistcoat? ;D
« Last Edit: December 17, 2018, 12:49:50 pm by smutts »

Reply #5December 15, 2018, 11:10:17 pm

ORCoaster

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Re: How much does winterr impact on fuel economy
« Reply #5 on: December 15, 2018, 11:10:17 pm »
Here on the West coast we are running about half that cost per gallon.  This is the time when diesel seems to compete against heating oil.  I never knew why either.  Maybe the refiners have a choice and choose to make more for houses and let us diesel drinkers pay a bit more. 

Some folks, just run the heating oil instead but they do take a chance of getting dipped by the state police and it could be costly having the wrong color come up on them. 

I doubt they would think to check a 1981 VW Rabbit,  But I don't take that chance.  Not when getting nearly 40 mpg.  The gas truck gets 16 - 20. 
Looking to add fender trim, LED lights and a bumper push to the truck soon.

Reply #6December 17, 2018, 12:57:24 pm

smutts

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Re: How much does winterr impact on fuel economy
« Reply #6 on: December 17, 2018, 12:57:24 pm »
Two diesels here, one for road use, the other for off road use.

The only difference is the fuel  additives,
Red dye for one, 63% tax for the other.


 

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