Winter and Summer mpg

[Jono8]

As we all know in the past few weeks temperatures have barely managed to pull themselves above a few degrees in most places and its barely gone near 10 degrees celcisus for a few months now.

Ive never seen a huge difference in fuel economy between winter and summer in previous cars (or i just havent bothered to notice) but i was pleasantly surprised today to see about a 10% hike on my way home today in this glorious sunny 16 degree heat! Normally on the same commute to work(car is a 2.0TFSI Octavia VRS) which is a 16 mile mix of villages, and B roads(30,40 and 50 limits) ive been getting about ~32mpg in the freezing temps. Today on my way home i was amazed to see it got nearly 36mpg door to door!

How much difference do you guys see going from freezing temps to 15 degrees+ (mild), and other than the car taking longer to warm up, what are the reasons behind this?

 

[Dave M]

Ever burned wood? It's much easier to burn once it's hot.

Starting cold requires things like fire lighters to get things going quickly.

Your reduced mpg is fire lighters (excess fuelling).

At least that's my mechanically challenged opinion

 

[paradigm]

My car is a good 8-10MPG more economical on my daily routine when the temperature is like it is today, as compared to anything below about 5ºc.

 

[[TW]Fox]

My car is a good 8-10MPG more economical on my daily routine when the temperature is like it is today, as compared to anything below about 5ºc.

Thats an insane difference! I get about 2mpg less in winter.

 

[paradigm]

I think I touched on it in either the "Show Us Your Motors" or the "Audi Owners" thread. But yes, struggle to get over 50 on a cold day, and easily get 60+ on a luke-warm day.

Can't comment on hot days as obviously I've not had the car during one yet!

 

[Minstadave]

I see mine drop from around 38 to 33.

 

[Jono8]

Even more remarkable is that i actually got pretty much the book figure for a combined/mixed journey!

 

[Clarkey]

No difference at all really.

 

[Jono8]

Interesting^ Although July and August did net you the best fuel economy and Jan - April was your worst. Not much in it though.

 

[Gaygle]

Interesting^ Although July and August did net you the best fuel economy and Jan - April was your worst. Not much in it though.

About 10% really, which is about the difference we are talking about.

 

[Deleted member 651465]

How many people record their mpg with fuelly?

http://www.fuelly.com/

 

[Matt82]

ive got the combined mpg on the golf to 33mpg now, im hoping for HUGE things when it gets warm

 

[Clarkey]

About 10% really, which is about the difference we are talking about.

27 is an anomaly really, I logged a tank at 19mpg after doing a trackday, I normally don't log fuel used on track.

 

[Jono8]

Ever burned wood? It's much easier to burn once it's hot.

Starting cold requires things like fire lighters to get things going quickly.

Your reduced mpg is fire lighters (excess fuelling).

At least that's my mechanically challenged opinion

So essentially, even when up to temperature, because of the low ambient temperature and the fact that the fuel in the tank will be cold, the car has to compensate by adding more fuel to the mix?

 

[acemastr]

Engine takes longer to warm up, the warm up process is dump fuel in(run it rich, used to do it with a manual choke)

 

[beermonster]

Mines dropped to around 18.3 but I use the car a lot less in the winter so I'm actually gaining cash

 

[Django x2]

Same, usually see 42ish mpg on the motorway jaunt but come the summer, 48/49 is easily achievable

 

[[TW]Fox]

Same, usually see 42ish mpg on the motorway jaunt but come the summer, 48/49 is easily achievable

What?

Surely the lower efficiency of an engine in the winter is because of the extended warmup time meaning it's more inefficient for longer. This isn't the cause on a Motorway jaunt as you'll be warmed up, so thats a pretty huge difference to notice on motorway trips.

Have you actually encountered that difference or is this story simply the manual 535d or perhaps Zopa loan return of the MPG world

 

[Uriel]

I tend to get around a 5 to 10 mpg difference for typical commuting between summer and winter. Low 40s is typical in winter. High 40s to low 50s is typical in summer.

My car has stop start, which basically never happens on my 9 mile each way commute in winter.

That's on a 2010 Honda Insight ES.

On my old Skoda Fabia 1.4 8v MPI I used to get around 25 mpg in winter and 33 mpg in summer for the same commute (last of the genuine Skoda engines before the VAG engineers got their teeth into the brand).

 

[Dangerous Dave]

I don't see a huge drop with my MK5 Golf GTI, tank average stays in the 31-33 range which it does all year. I think a few things contribute to the small difference, the car is garaged so less time to warm up in the winter, the aircon compressor is mainly off from the start of November to around the end of Febuary as it cuts out under 4c and I also do a lot of my trips with bikes on the roof but over winter I do slightly less of these (3 or 4 bikes on the roof can knock 20-30% off depending on wind levels)