Fuel economy :-(

[Paul]

Hi everyone, I've noticed over the last couple of days economy on my 115 Dsport has gone really poor, I've done just over 5000 miles in it always averaging over 55mpg. I've noticed the average has dropped into the high 40's, and the instant consumption goes as low as 15mpg when accelerating under normal conditions??? It's booked in at the dealership next week but anyone any ideas? Ps it doesn't seem to be driving any different! Thanks :-)

[Bigfeet]

With the change in the weather and temperatures falling the drop in the MPG, in my mind, would be quite normal. My DSport when the winter came would settle in about around 50 MPG.

Please bear in mind if you are basing your assumption of poor figures from the official MPG then understand that these numbers are not to be used for road driving but are for comparative purposes only.

[Paul]

Hi Mr large feet, I appreciate the book figures are based on optimum conditions ie flat roads, zero wind resistance etc but I am comparing my current figures based on those I've been achieving over the last 5000 miles! Around town I've never seen the mpg drop into the teens and 20's like it is now? I've never hesrd of the cold weather adversely affecting mpg but I'm certainly not disagreeing with you, I have asked for advice after all! Paul

[scubagazza]

Hi Paul, ref your drop in mpg. It's down to the colder weather as Bigffeet says. my old Nissan Juke Diesel used to show around 4mpg less on average over a tank of fuel during cold weather and that was nowhere near as good on fuel as my new DS3.
Gary

[sted]

cold really does affect it quite badly. iirc its more to do with air density than actual temp as colder air is denser so dosent compress in a turbo as well iirc
wouls upload my spreadsheet but 42k is too big for a pdf on here lol

[peter m]

http://www.greencarreports.com/news/...ther-heres-why

have a read.

[Paul]

Thanks guys, very helpful........ Again :-)

[DavidDS3]

If cold air is such a handicap, why do manufacturers fit an intercooler?? The reason why diesels get thirstier in cold weather is coz they don't reach an optimum operating temperature as quickly.That's why in really cold climates, a winter grille is often used to block cold air blasting through onto the engine block etc. In my experience I am suffering about a 4mpg deterioration in fuel consumption over comparable journies in the winter versus the summer

[Shrek]

55MPG - Thats good


I took my 120VTI on a Run from Manchester to Bournemouth - Keeping to the Speed Limits and never went over 49.3MPG

[Paul]

Well I've made a few little trips round town today, driving really nicely, no harsh acceleration and just feathering the throttle, over 10 miles its averaging 28 mpg!!! I've literally been changing at about 1800rpm when the gear change light illuminates. Surely it shouldn't be this bad and it was 9 degrees outside, much warmer than the previous week! I filled up yesterday and the range is only showing 385 miles!!!

[lfcrule1972]

Mine is still behaving and on last fill said the range was 600 miles ish, to be fair I won't get that though as I'm mostly doing town driving at the moment

[joeking27]

Cold engine and slow speeds will cut your mpg. I've had a drop of 10-15% since my commute went from 30 miles to 3.5 miles commute.

[Paul]

I suppose I won't be able to tell until I balance it out with a good drive on the motorway! Thanks so far everyone :-)

[aries driving school]

I do 35k a year as a driving instructor and my present DS3 16HDI on 17" alloys will avg 53/54mpg with a roofbox. In winter this will drop to 50/51. My first ds3 with 16" wheels was 2/3 miles better.

[Sash]

My 90 averages about 48-50mpg - depending on how many newbies I have (theres a fair bit of idling at the side of the road explaining things) but I do give it hell when I drive it to keep it clean.