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Freezing cold temps = better induction = more MPG?


Karlp

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The last week and a half with the cold temps I've been able to manage around extra 30 miles to the usual £50 of 97 Ron I stick in my tank, I usually only manage 110 miles max from a £50 fill up, that's with all around town driving, think my odo trip was at 152 mils with around 20 odd left on the DTE indicator, could the cold air give better induction causing better MPG???

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Colder air is denser air.

Thus you get a greater volume of oxygen for each combustion cycle = greater bhp

We are talking tiny amount though.

 

It's more likely that you are just driving slower due to majaority of people being a little more careful on the roads, using less throttle etc.

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Colder air is denser air.

Thus you get a greater volume of oxygen for each combustion cycle = greater bhp

We are talking tiny amount though.

 

It's more likely that you are just driving slower due to majaority of people being a little more careful on the roads, using less throttle etc.

 

 

+1

 

 

Any improvements in performance will be small as denser air also means more air resistance. At speeds over 60 you would probably see your MPG drop off.

 

 

Pete

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Cold air = dense air = more fuel = lower MPG ;)

 

As the others have said, you must have just been driving slower. Actually the bad weather means everyone actively tries to drive smoother, less accelerating/braking etc which will increase your MPG. With slow people infront of us on Saturday, the Alfa (TDI) got 53MPG whereas we usually average 45MPG on the same 20 mile trip.

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The last week and a half with the cold temps I've been able to manage around extra 30 miles to the usual £50 of 97 Ron I stick in my tank, I usually only manage 110 miles max from a £50 fill up, that's with all around town driving, think my odo trip was at 152 mils with around 20 odd left on the DTE indicator, could the cold air give better induction causing better MPG???

 

You get 110 miles from £50!

 

That's crazy, and like 14 mpg!

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I always get worse mpg when its cold. Even more so on my diesel cars.

Strangely, with the Alfa being our first TDI, we are finding less of an impact from the cold compared to the Zed. However, that might just be better right foot control in the Alfa than the Zed :blush: Zed seems to drop a good few (3-4) MPG in the cold whereas the Alfa stays about the same - maybe 2MPG different. Guess it depends how the engines are designed :shrug:

 

Definately though, cold air is more dense and the ECU will adjust to use more fuel to compensate. Also, as the engine takes longer to warm up the engine will run open loop for far longer than when its warmer outside, which results in it running richer and using more fuel.

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I always get worse mpg when its cold. Even more so on my diesel cars.

Strangely, with the Alfa being our first TDI, we are finding less of an impact from the cold compared to the Zed. However, that might just be better right foot control in the Alfa than the Zed :blush: Zed seems to drop a good few (3-4) MPG in the cold whereas the Alfa stays about the same - maybe 2MPG different. Guess it depends how the engines are designed :shrug:

 

Definately though, cold air is more dense and the ECU will adjust to use more fuel to compensate. Also, as the engine takes longer to warm up the engine will run open loop for far longer than when its warmer outside, which results in it running richer and using more fuel.

 

On my Golf GT TDI id get about 50mpg in winter and during the summer months that would go up to 58mpg upwards. Id easily get 63mpg on a drive home from work in summer. Think its cos diesel gets pretty thick in winter compared to summer. Your right though. Right foot control does help. I find when im driving a diesel i tend to just poodle along at 70mph on the dot and really try to drive economical.

 

With my old turbo renault 5, id definately notice an increase in power when it was cold. But then turbo cars are more prone to heat soakage etc... and cold air makes a difference.

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I could only eek 38mpg from my TDI on a 100 mile round trip yesterday :shrug:

 

Im getting 48mpg from a Peugeot 307 2.0HDi and the missus`s new 1.5 Dci Juke atm.

We're on roughly 48MPG too from the Giulietta 2.0TDM2. Was up at 53MPG on Saturday when we had a little drive and got stuck at 55MPG for quite some time (sitting in 6th)

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Think its cos diesel gets pretty thick in winter compared to summer.

 

 

Indeed it does :thumbs: . Between say 1 degree to 25 degrees centigrade there would be no noticeable difference but at 0 degrees it begins to cloud and then at about -10 it will start to gel and at -18 or so it will start struggling to reach your engine. By -35 it'll be for all intents and purposes solid :) . If the forecast is for nights of below -15 then a good tip for diesel users is to make sure your tank has plenty of fuel in it as larger volumes take longer to freeze. We've all probably seen scenes of truck drivers lighting fires underneath their fuel tanks in places like the Yorkshire Moors :scare:, so what happens in places like Canada and Finland where temperatures can drop to -30 quite often. Well, over there they add a pour point depressant to the diesel which means that the freezing point is lowered to -55 or so. It never gets added in The U.K but there should be additives available to buy.

 

Never had a diesel, but in the winter of 1981/82 my heating oil turned into jelly when nightime temperatures hit -18 for several nights running :cold: . No problem with petrol though, it doesn't freeze out till -70 :lol:

 

 

Pete

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The last week and a half with the cold temps I've been able to manage around extra 30 miles to the usual £50 of 97 Ron I stick in my tank, I usually only manage 110 miles max from a £50 fill up, that's with all around town driving, think my odo trip was at 152 mils with around 20 odd left on the DTE indicator, could the cold air give better induction causing better MPG???

 

You get 110 miles from £50!

 

That's crazy, and like 14 mpg!

 

agree for £60 on super unleaded I am getting around 298 miles to quarter of a tank left. I never let the 350Z run below quarter of a tank.

 

I do 36 miles round trip a day and its town and country.

 

Does sound like your fuel consumption is crazy imo.

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