Increased fuel consumption in winter?

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abre

abre

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Happy New Year to all A2 Forum members [24]

Being a relative newcomer to diesel (A2's 1st birthday in a few weeks :) ) Is it normal to take a hit (7-8 mpg less) on the fuel consumption when the weather gets colder or is this down to the new Shell diesel or has my right foot just got a lot heavier with the Christmas shopping traffic! [3]

Bah Humbug (Stuart, where's the grin gone?)

Andrew - 2003 1.4 TDI Silver Climate
 
Andrew,

No, it seems to be normal. I did 400 miles over new years, all motorway driving at approx 70-80mph. Normally I get between 57-60mpg on these runs, however this time it was 49.8mpg (probably the worst avergae I have ever had)

Kaine
 
Hi Andrew,

I've noticed that too during the recent cold spell.

It's probably got something to do with the supplementary heater on the TDi. This kicks in at temperatures below +5 degrees C and helps warm up the interior of the car much more quicker. The downside is a reduction in mpg. You can switch off the supplementary heater by pressing the ECON button but personally I've found it much better on, especially during the recent frosty mornings.

Hope this helps
Shaf

Nov 2002 TDi Sport, Silver,Black/grey interior,climate. Replaced previous Mar 2001 TDi SE
 
[7]
The aux webasto IS the culprit which is why it is no longer fitted. Instead of a coolant heater there is now an electric element of approx 750 watts downstream of the heater matrix so that it heats the interior only. It no longer speeds up the heating of the coolant.
[7]

Your mind is best used like a parachute - OPEN
The UK does not have bad weather - we have the wrong clothes
 
Apologies in advance for my A2 ignorance, I'm currently in the process on upgrading from a sh*troen paxo VTR, which has no toys, to an A2 TDi Sport, which has oodles!

Does the existence of an electric element mean that I will no longer have to wait for the engine to warm-up before I can enjoy warm air in the cabin?

Phil. Anxiously awaiting collection of a TDi Sport with Climate and OpenSky...
 
I always thought that colder weather helped fuel consumption-thicker air, better combustion. Or is this just the petrol engine.

Don't laugh at me if I've got it wrong. I'll post Christmas chocolate to you until you can take no more if you do laugh.

Steve - 2002 1.4SE petrol, Silver, black/black interior, Then an identical replacement 2003 A2. Now a Toyota Corolla 1.6 T-Spirit
 
quote:Originally posted by maersk


Instead of a coolant heater there is now an electric element of approx 750 watts downstream of the heater matrix so that it heats the interior only. It no longer speeds up the heating of the coolant.
Click to expand...

Maersk - Do you know you supplies the PTC element - is it webasto / Catem, or a another? I am suprised they fitted a PTC, since wouldn't this mean a major change to the wiring and electrical power consumption? Did this change for the 2003 model year?

Kaine

P.S. The PTC does still help bringing the engine temp up, as it raises the coolant temp as it passes through the heater core - assuming the PTC is located immediately after the Heater core as in most cases
 
Steve,

having been a petrol head for more years than I care to remember I have to agree with your thought, must be a petrol thing... Perhaps its whatever they add to diesel to stop it waxing up as used to happen in days of old - when building a fire under a lorry to get it started was often seen, so we beat the french to that trick, oh but we only cooked the block not the load!!! Baaa Baaa Baaa

As for the Webasto my TDI is one of the newer versions with the electric heater and this only makes a couple of MPG difference when used.

Andrew - 2003 1.4 TDI Silver Climate
 
[24]
The denser (that should be more dense I think)air in winter will make all engines run better. They will develop more power BUT they will take longer to heat up and therefore use more juice in the process as the mixture needs to be richer at startup and during cold running. Cold engine that is,
the cold air allows a better charge rate of the cylinder and more liberated power.
The old two stroke bikes (and SAAB 93's) used to go like stink in the winter. They had no coolant to heat of course.
The PTC does not heat the coolant only the air downstream of the heater matrix therefore only the cabin air.
Instant Heat. The A3 has a 1kw element and blows hot[7] as oppoased to warm air immediately. the alternator and accumulator must be awesome!
I don't think there has had to be a change as the PTC was an option in some countries.
Now the PTC is standard and the 'webasto' auxiliary heater is an option. If you opt (in some markets) for the aux heater the PTC is deleted.
I believe the 2002 model year had the change as a running mod.

Your mind is best used like a parachute - OPEN
The UK does not have bad weather - we have the wrong clothes
 
Maersk,

I saw a presentation from Catem last year indicating that the PTC also helps heat the engine coolant temp. It was only a bi-product of the heater, since it is normally located by the heater matrix - Catem were showing it as a benefit, however I never saw actually data.

Kaine
 
I've also noticed the same effect in my FSi.
Dropped to about 42 mpg from 46 over the last month or so.
I haven't been using climate which given the consumption a hit!


2002 FSi SE, Ebony Black with Red Nappa Leather, 17" Sport Wheels, Tinted Security Glass
 
In winter you tend to have lights on more, this places a larger load on the alternator and accounts for some of the additional fuel. Just add up how many watts worth of lights are on!

Ian

2002 1.4 Petrol SE, silver with climate control.
Why are NEARLY all the A2s in Lichfield are silver ? ? ?
 
Good Point Ian. Also, isn't correct in saying electrical components use more power in the cold - or did I dream that?? If so, try not to use the sky roof so much in the winter ;)

Kaine
 
I suppose you could attribute some other factors to winter:

Rear window heater on more often
Washers used more to clear dirty windscreen
Fan on a higher setting to warm up the cabin



Steve - 2002 1.4SE petrol, Silver, black/black interior, Then an identical replacement 2003 A2. Now a Toyota Corolla 1.6 T-Spirit
 
Almost entirely down to the time it takes to warm up the engine block - so maersk is right in his 2nd post. The original Mini would average around 10 mpg for the first 5 mins or so - you'll notice it more on short journeys around town. i loose about 10% on the 1.2TDi in winter but this is also down to knobbly winter tyres

The new Mini Cooper S does 13 mpg round town! Great 1.6 Petrol the Yanks designed eh!



Lukas

First A2 1.2 TDI in UK
Style pack + Chorus + Advance pack + winter wheels + iRiver MP3CD


http://www.audi-a2.co.uk/mar.htm
 
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