Work this out - because I can't

[Sheldon.Cooper]

Just completed a 2 day return trip from Newcastle to Stoke.  Filled car up in Newcastle before I left, nothing changed whatsoever between journeys.

 

Going there took 2h 35m and I averaged 68mph and 46.5mpg

 

Coming back took 2h 44m and I averaged 67mph and 57.6mpg

 

It wasn't all uphill going there and downhill coming back.... what the hell happened to get 10mpg better under the same conditions?

 

The only thing that was different was that going there I was in Sport mode and coming back I was still in sport mode (didn't change anything) but on maxidot it said D instead of S next to the gear number.

 

Seriously confused... happy but confused.

[mannyo]

Headwind on the way there and behind you on the way back. Wind can have a dramatic effect on MPG.

[Sheldon.Cooper]

Headwind on the way there and behind you on the way back. Wind can have a dramatic effect on MPG.

I agree it can but it wasn't that

 

Every journey I have done over the past 4000 miles I have never bettered 46mpg - so going there was bang on, coming back was ???

Edited 24 February, 2014 by Sheldon.Cooper

[tuonopepper]

Yep, I'd agree wind factor probably. Was load any different (bar the half a tank you used going up not being there?).

[Sheldon.Cooper]

Yep, I'd agree wind factor probably. Was load any different (bar the half a tank you used going up not being there?).

Already said, nothing changed, weather was +/- 0.5 degrees difference between both days, no wind to speak of.

 

Nothing changed load wise, tyre wise, anything other than I left it in sport mode (Sport displayed on Amundsen, mode button light on) but showed D on maxidot and changed gear at normal revs (i.e not at sport revs) but engine performed as per sport setting!

[Dempsek]

The DSG box was in sport mode on the way there S1 to 6 in maxi dot and changes gear very high up in the rev range on the way back the DSG was in normal mod D1 to 6.

 

Sport mode and normal mode can be selected by pushing the gear stick back against the spring, if in sport push back for normal or vice versa normal to sport.

[countryboy]

It is very surprising what difference a little wind can make, I regularly drive along the A27/M27/A31 and the MPG usually is in the low 50's heading east and high 40's heading west, all I can put it down to is the strength of the prevailing southwesterly wind.

Ian

[Sheldon.Cooper]

The DSG box was in sport mode on the way there S1 to 6 in maxi dot and changes gear very high up in the rev range on the way back the DSG was in normal mod D1 to 6.

 

Sport mode and normal mode can be selected by pushing the gear stick back against the spring, if in sport push back for normal or vice versa normal to sport.

yes, the gearbox was in normal mode even though it should have been in sport (everything said it was in sport). I agree.

 

maybe I've got a new super mode, I'll know better tomorrow when I do my normal commute.  I know exactly what my mpg to/from work is so I can gauge any difference then.

 

Really happy with watching the instantaneous mpg read 70+ mpg on a flat piece of road, normally reads mid 40's.

 

And I wasn't exactly not making progress.

[Mike999vRS]

There was someone else with the phenomenon on here.

I reckon folk figured it was wind direction and/or gradient.

You'd be surprised how many hills you don't notice on a motorway. If been on foot on a few and it's only when's you stop and get out you realise there are hills where you didn't realise there were any!

[bichti]

Already said, nothing changed, weather was +/- 0.5 degrees difference between both days, no wind to speak of.

Nothing changed load wise, tyre wise, anything other than I left it in sport mode (Sport displayed on Amundsen, mode button light on) but showed D on maxidot and changed gear at normal revs (i.e not at sport revs) but engine performed as per sport setting!

I think if there was 'no wind to speak of' then you may have been in another country?

We had strong winds from late last week and over the weekend in Scotland/Northumberland and Yorkshire (I deal with weather issues a lot). It would have made quite a difference in terms of mpg if you had headwind which is likely to have been the case.

[Sheldon.Cooper]

Same route, just reversed so surely what goes up must come down... true in both directions.

 

Over 184 miles there can't be a near constant gradient going upwards when going from Newcastle to Stoke.

 

AND in every journey I've done since the car was new on a motorway in any direction I haven't bettered 46mpg, best ever was 53mpg at 55mph. 

 

Considering I averaged the same speed both ways, I wasn't doing 55.

[bichti]

I should add that Sheldon Cooper would never admit to not being able to work something out.

[@Lee]

Sheldon Cooper in The Big Bang Theory's 'The fuel consumption paradox',,,,,,

[countryboy]

Or you could have just passed a stage in the engines life where it loosens up a bit and gives a jump in MPG. Mine did so at about 10,000 and 30,000 miles and my overall average in maxidot has gone from high 30's to high 40's MPG as a consequence.

Ian

[Mike999vRS]

Same route, just reversed so surely what goes up must come down... true in both directions.

 

Over 184 miles there can't be a near constant gradient going upwards when going from Newcastle to Stoke.

 

AND in every journey I've done since the car was new on a motorway in any direction I haven't bettered 46mpg, best ever was 53mpg at 55mph. 

 

Considering I averaged the same speed both ways, I wasn't doing 55.

The first part is true but it's all about the length and degree of the slopes - going to work I can't better 46mpg but can do 52mpg coming home.

I'd love to see about 60mpg on a flat steady run but struggle to get above 50 so I'm looking forward to my mystical jump!

[banksie]

Definitely the wind! Its from the right direction ie South westerly. So tailwind

You'd be surprised what the wind can do to mpg.

Any aircraft leaving the US will be fuelled with not enough to get to the UK in still conditions. But with the tailwinds across the Atlantic it allows it to complete the journey and have about 10000 litres left when it lands!

[skovirg]

Definitely the wind! Its from the right direction ie South westerly. So tailwind

You'd be surprised what the wind can do to mpg.

Any aircraft leaving the US will be fuelled with not enough to get to the UK in still conditions. But with the tailwinds across the Atlantic it allows it to complete the journey and have about 10000 litres left when it lands!

 

I'm so glad that engineers can do their sums...

[banksie]

I'm so glad that engineers can do their sums...

Its always surprising how "right" they get the wind over the Atlantic yet they can't get the weather forecast right even if they look out of the window!!!

[andyvee]

It's obvious isn't it - if you travel North it is always uphill as there aren't any proper hills down south ......

 

Takes cover..........

[JungleJames]

It's obvious isn't it - if you travel North it is always uphill

You are right there. Afterall, the South is meant to be falling into the sea all the time. Something to do with the fact Scotland has lost its ice caps.

[Mike999vRS]

You are right there. Afterall, the South is meant to be falling into the sea all the time. Something to do with the fact Scotland has lost its ice caps.

From what I've seen on the news it is falling into the sea!

[GroundHog]

One assumes you also had a slightly more empty fuel tank coming home, as you only filled up before you left Newcastle, so less weight onboard.

 

The wind make a massive difference though. Driving down south the other Friday when it was really stormy and I got 41mpg in my A4. Coming home with no headwind and I was back to my regular 53mpg. Same driving conditions otherwise.

[SC03OTT]

I'm not seeing the mystery here. No two journeys are the same so it's no surprise - to me anyway - that there is a difference. Traffic, weather and geography will be different.