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hi. does anyone know if the cold weather (well its cold here up north) reduces fuel consumption ? the tpms warning has been on for weeks now .to be honest I don't know what the pressures were when I go the car but its saying 29 when cold ,however a tyre pressure guage is showing 32. is the fuel consumption linked to tyre pressures as ive had a drop in consumption in the last couple of weeks .what should the pressures be on a 1.4 turbo on normal light mode ? cheers all .
 

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...more than 29!. Tyres that low will increase consumption. Comfort setting is about 30, Eco is a lot higher. It is in the manual for your engine and should be on the door pillar, though probably not in PSI.
Ignore the gauge, your TPMS will be more accurate.
 

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It won't just be the cold, it'll be the fact it's darker and that you will have had your lights on most of the time too.

You likely have your heaters on for most of your journey too.

Anything on in the car will be causing extra consumption of fuel.

Pressures should be 34 according to my dealer - though it's beneficial to have lower PSI in winter to give more traction.
 

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Yep as said above, tyres running at 30psi or lower will cost you a fair bit on mpg compared to higher pressures. I run mine at eco pressures which give approx 5% better mpg than on comfort pressures.

However even I've noticed big drops in mpg in all my vehicles through winter. I've been recording my mpg on fuelly and spreadsheets for years so can see a clear pattern.

I did some back to back testing in my last vehicle and found that having lights on 100% of time compared to 0% will cost you about 5% mpg.

Having heater on will cost you another 5% or more, lots more on a small alloy engine because to heat you up it takes heat from the coolant and that cools the engine down. A cool engine is not efficient so your mpg tumbles. All alloy engines like the 1.0T struggle to heat up anyway but even the 1.4's have alloy heads so suffer from too much heat dissipation in cold weather.

The more electrical items you have on the worse your mpg will be. Heated screens, steering wheel etc will cripple mpg as they draw huge current which adds extra load to engine to turn alternator. An alternator under load is far more difficult to turn than when under no load as the magnetic field increases in proportion to current draw.

So basically doing 100% of your driving with lights, heater and lots of electrics on plus running on low tyre pressures will give you 15-20% worse mpg than doing the same trips in daylight on a warm summers day with no lights, heater or heated screens etc and running at eco pressures.
 

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mud4fun said:
Yep as said above, tyres running at 30psi or lower will cost you a fair bit on mpg compared to higher pressures. I run mine at eco pressures which give approx 5% better mpg than on comfort pressures.

However even I've noticed big drops in mpg in all my vehicles through winter. I've been recording my mpg on fuelly and spreadsheets for years so can see a clear pattern.

I did some back to back testing in my last vehicle and found that having lights on 100% of time compared to 0% will cost you about 5% mpg.

Having heater on will cost you another 5% or more, lots more on a small alloy engine because to heat you up it takes heat from the coolant and that cools the engine down. A cool engine is not efficient so your mpg tumbles. All alloy engines like the 1.0T struggle to heat up anyway but even the 1.4's have alloy heads so suffer from too much heat dissipation in cold weather.

The more electrical items you have on the worse your mpg will be. Heated screens, steering wheel etc will cripple mpg as they draw huge current which adds extra load to engine to turn alternator. An alternator under load is far more difficult to turn than when under no load as the magnetic field increases in proportion to current draw.

So basically doing 100% of your driving with lights, heater and lots of electrics on plus running on low tyre pressures will give you 15-20% worse mpg than doing the same trips in daylight on a warm summers day with no lights, heater or heated screens etc and running at eco pressures.
That does seem to correlate with my Fuelly too. I'm struggling to get more than 40ish MPG per tank at the moment, whereas usually I can get up to 44-45. My commute only gets about 48, instead of 58 too at the moment!
 
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