Hi All,

I noticed last winter and this time again that the fuel economy on my Furby 1.9TDI estate drops from around 60mpg to 50mpg if temperatures are below 10 degrees. It's not just on short trips where warm-up time is a large part of the drive but also 1+ hour runs on motorways and A roads.

I guess that is not too unusual. What's your experience in winter?

Cheers, Michael

Always poorer....it's to be expected. Not only does the engine take a lot longer to warm up but the incoming air is colder and more dense. This means effectively more air is going into the cylinders and thus more fuel must go in to maintain the fuel to air ratio. Means you do get more power though!

Mine got an average of 50mpg last week (brim method) mainly because the weather was a bit warmer (albeit wetter too) I think. Normally it's about 46.

EDIT - Apparently even on full load most diesels run at about 50% lean of stoichiometric. You can reduce that figure but then you're into the realms of overfuelling and you end up with lots of soot. You therefore need more air! Increased boost, more efficient intercoolers and less restrictive intakes come in here.

I've had diesel cars for 20years, it's the same every winter,my last felicia 1.9gld used to do 45mpg in winter ,52mpg summer always the same. My 1.4Tdi did 48mpg last week when i filled it up, 40 mpg the time before, last August i had 57mpg out of it. I have been expecting more mpg, it didnt matter how you drove the felicia it never varied so much. But the fabia goes much better.

Garages sell you a different grade of diesel in the winter, with plenty of anti waxing additives, which is less efficient than the summer grade stuff.