mpg in cold temperatures

[begbie]

My TDI Ref Sport was reading -5.0 this morning! On the 30 minutes drive to work the mpg slowly increased from 8mpg to 28mpg

Does the cold weather have an effect on the mpg? I would't have thought so.

Normally, on the same journey I can get around 36 - 42mpg. Last night driving home from work (temperature was around +2.0 degrees C) I averaged 44mpg.

Any explanations?

 

[Tam]

I bet you left it running one your drive/road while it defosted.... hence lower mpg.

 

[begbie]

Ahah!

Didn't think of that one! I knew there had to be a logical explanation

 

[fivetones]

If you cane the car before it gets warm it generally uses more fuel too.

 

[sssstew]

yep, it takes longer to reach peak operating efficiency temperature in the cold.

 

[hoooverman]

Also on mine this morning, i left my house with 60 miles showing left in the tank, fuel gauge was well over a quarter. 10 miles into my trip whrough country lanes, i worryingly had 15 miles left reading, gauge was looking very worrying. Sat in the queue to the petrol station i realised i had had my fans on high temp setting. Dropped this and the fans, and the fuel left went back to 30 miles. Does it have a high drain having the heat on max and blasting?

I know miles in tank is only an indicator and must work with the avergae mpg reading, but this was steady all the way...

(btw after filling up, drove for 2 miles in 6th / coasting and notched up 83mpg average!!!) - are we that sad we care!!!

 

[dchbrown]

I do like to see what my mpg is but at the end of the day there isnt massive amounts you can do about it.

If you want to use the car you put fuel in it - if it uses more you put more in

 

[BanziBarn]

Also on mine this morning, i left my house with 60 miles showing left in the tank, fuel gauge was well over a quarter. 10 miles into my trip whrough country lanes, i worryingly had 15 miles left reading, gauge was looking very worrying. Sat in the queue to the petrol station i realised i had had my fans on high temp setting. Dropped this and the fans, and the fuel left went back to 30 miles. Does it have a high drain having the heat on max and blasting?

I know miles in tank is only an indicator and must work with the avergae mpg reading, but this was steady all the way...

(btw after filling up, drove for 2 miles in 6th / coasting and notched up 83mpg average!!!) - are we that sad we care!!!

You should also notice a difference (but a positive one) if you use the Econ button on the climate control. I have it on Econ all the time in the winter apart from when I want to demist the window and for 5 mins a week to keep the compressor ticking over.

But I'd have thought the car would be more economical once up to temp because the cold air gives more torque hence better economy ( as long as you don't use the torque to go faster!!).

Also, filling up in the cold is better value for money because the petrol in denser and you get more per litre!

 

[sssstew]

the miles to the tank indicator takes an average of the last x many miles, so it sort of says "if you continue druving how you are you will get...."

 

[hoooverman]

I do like to see what my mpg is but at the end of the day there isnt massive amounts you can do about it.

If you want to use the car you put fuel in it - if it uses more you put more in

Exactly. Why buy a 2.0 car to drive it like a grandad on a Sunday!!! If you want to get to timbucktoo and back on a quarter of a tank, buy a ... erm... very economical car!!!

That said, i think the 2.0 TDI is sufficiently economical!

 

[fivetones]

To get this into perspective every time I've had the car (I share it with my partner, it's mostly hers though) I've been keeping an eye on economy as sometimes the traffic won't let you go fast or whatever. I've found if I drive like my dad I get about 42 mpg on 25 mile run and if I drive it like i want to I get about 39 mpg.

I still think the 1.9 TDI 130 engine we had in the beefa was much more economical, but then again that was lighter and had 40 less horses.

It'd be interesting to see what the 1.9TDI leon2s get.