What causes drop in ...

[HandyAndy]

Tell that to the Gendarme when you get caught,,!

?
My commute car spends its life behind hgvs at 55 mph, never even had a copper glance at me, let alone get pulled for it... been pulled for plenty of other things though. ???

 

[Spriddler]

I was well over speed limit for considerable distance. So it may be MY fault.

Yup, probably that. Be cool and check after another tankful before spending any money with a mechanic.

 

[movan]

Yup, probably that. Be cool and check after another tankful before spending any money with a mechanic.

Will do. Think you are right.

 

[Just smiffy]

Agree with Spriddler movan .... going faster then you normally do will use a fair bit more fuel but, on the plus side it probably did the engine good to give it a bit of a blow out, especially if your normally conservative on your speed...??

 

[Mr Chrysalis]

Do you use an app to track the mpg or are you guessing?

View attachment 328420

Are you trying to make us believe you are getting between 59 and 77 mpg in a Fiat Ducato 2.8? I must be heavier footed than I thought!?

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[HandyAndy]

Are you trying to make us believe you are getting between 59 and 77 mpg in a Fiat Ducato 2.8? I must be heavier footed than I thought!?

I wish I was ?, naa this is a 1.5 diesel in a 106. Good old bit of pig iron that thing. ?

 

[buttons]

I have noticed our MPG always suffers when the temperature drops..
For instance, in January going to Spain we average 21.2 mpg
Coming home mid March it goes up to 22.5+ MPG

This has happened every year for the past 11 years .. and we are always heavier coming home than going

I would have thought it would have the opposite effect, engines tend to run more efficiently with cold more dense air intake. But then I guess driving a square box through thicker air could also make a difference but I don't have any calculations for that... .

 

[Baldeagle7470]

Joy,not sure if anyone has already mentioned but fuel filter can make a difference if not changed at the service.
Good luck resolving this problem.

 

[Jaws]

I would have thought it would have the opposite effect, engines tend to run more efficiently with cold more dense air intake. But then I guess driving a square box through thicker air could also make a difference but I don't have any calculations for that... .

Yep.. It never fail =s to surprise me either.. but the old Miller we had was the same ( 2.8 Ducato )

 

[HandyAndy]

A petrol turbo seems to love the cold weather much more than the hot weather but I never took any notice of the mpg in my old car as it made me weep (around 7 mpg)
But the stats on my non turbo diesel definitely favour the summer months for increased mpg. I think a lot of it is the fact you don't have the lights heaters, demisters and wipers on a lot in the summer so the alternator drag is reduced massively.

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[TerryL]

Are you sure that you actually loaded what the pump indicator said? A faulty garage pump is not unheard of.

But for me headwinds always make a very noticeable difference, especially if I'm trying to push on a bit. I keep a detailed record on a spreadsheet I downloaded off here some years ago.

 

[davejen]

I worked out how many gallons of petrol I had used for the journey and the miles my satnav said I had travelled.

PETROL?????
Cheers, Dave

 

[Jimbohorlicks]

PETROL?????
Cheers, Dave

Well spotted. movan?

 

[airwave]

Tell that to the Gendarme when you get caught,,!

Or plod in this country , it's actually illegal .

In this case i gotta go with the increase in speed , however the way other people drive , can affect your own mpg , kid . Someone driving badly in front of you , can cause you to make abrupt changes in your own vehicle .

 

[Mickthemove]

Wind and hills are the big killers of MPG, my work vans normally get great mpg going west to east and poor on the return, and that is when it is flat, add a few inclines and it nosedives

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[mitzimad]

We always get better mpg in mountains for each up there's a down hill stretch

 

[Paul and Kate]

I'm pretty certain Joy's mh is diesel but not sure what size engine it is.
Cab is Renault master

 

[movan]

PETROL?????
Cheers, Dave

Oops .. diesel...

 

[Off da Grid]

Using anything that pulls power will effect fuel consumption.
Air con is the worst, having heaters and headlights comes next.

 

[Jasz]

Last year in France around 1000 miles of good fuel consumption was undone by 300 miles into a strong cross/ head wind and I wasn't going that fast!

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[Cheshirecat57]

We prefer to call it slip-streaming
I believe triathletes call it drafting (or draughting?).

Or Dafting

 

[Cheshirecat57]

I would have thought it would have the opposite effect, engines tend to run more efficiently with cold more dense air intake. But then I guess driving a square box through thicker air could also make a difference but I don't have any calculations for that... .

Me too- colder means better- hence intercoolers

 

[tonyidle]

When driving something with the aerodynamic qualities of a block of flats only two things seriously influence fuel consumption: speed and wind strength & direction. IMO of course

 

[Spriddler]

Many years ago I drove my 5 speed 998cc Bambi camper to La Rochelle, directly into a South Westerly blow and was in 4th much of the way, even on the flat, getting about 25mpg instead of the usual 35 to 40.

 

[2657]

Using anything that pulls power will effect fuel consumption.
Air con is the worst, having heaters and headlights comes next.

I would say from observation that the effect of aircon is minimal, especially compared to relative wind speed, 50 mph into a headwind of 40 mph is a relative velocity of 90 mph.

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[Loveshack]

Letting the gap between me and the HGV in front grow to more than 6ft. Once a cyclist, always a cyclist -- tuck in behind the big guy when the wind gets up

Now that’s worth thinking about. I wouldn’t get anywhere as close as that, but I might not be in quite such a rush to get in front next time.
Trouble is, the near side lane ( of 3 ) does feel a bit slow, and the HGVs do restrict the view. I’ve not noticed any major surges in mpg, up or down over the years.

 

[HandyAndy]

Me too- colder means better- hence intercoolers

denser air contains more oxygen, the denser air (and temp) is measured by the by the mass air flow meter and fuelling calculated accordingly. so while cold air will give you more power, it will not necessarily make it more "efficient" as it will use more diesel in the process.
More air mass = more diesel injected

 

[Northernraider]

Letting the gap between me and the HGV in front grow to more than 6ft. Once a cyclist, always a cyclist -- tuck in behind the big guy when the wind gets up

And pray he doesn't hit the brakes hard and suddenly

 

[HandyAndy]

And pray he doesn't hit the brakes hard and suddenly

my 875kg car is going to stop quicker than a 44,000Kg artic

 

[Northernraider]

my 875kg car is going to stop quicker than a 44,000Kg artic

Maybe.

A load of bikers with fantastic brakes die thinking the same thing

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