MPG....speed related savings

May 29, 2012
3,821
5,862
Funster No
21,238
MH
Not currently
Exp
Since 2013
After nearly 20000 miles in our Fiat 130hp van I have observed the following:

50 mph gives 43 mpg

60 mph gives 35 mpg

70 mph gives 28 mpg

Generally depending on how quiet/busy the roads are, I tend to cruise between 50 and 60. All these speeds are 'indicated' and in reality are about 4mph fast according to the GPS

My average overall is 38mpg

The 'shocker' is that going just that little bit faster uses a massive amount of extra fuel for little saving in time and a lot more stress.

I am referring to constant speeds set with cruise control where possible. It does of course depend on the type of journey and time available.

For me...... cruise control on......music on....,. Sit back and relax :):)

The journey takes a little longer and I spend less on diesel. It works out to be a 'free' bottle of wine every 100 miles :D
 

Bertie Bassett

Free Member
Jul 25, 2014
2,743
8,717
Funster No
32,543
MH
C Class
Exp
since 1988
After nearly 20000 miles in our Fiat 130hp van I have observed the following:
50 mph gives 43 mpg
60 mph gives 35 mpg
70 mph gives 28 mpg
Generally depending on how quiet/busy the roads are, I tend to cruise between 50 and 60. All these speeds are indicated' and in reality are about 4mph fast according to the GPS
My average overall is 38mpg
The 'shocker' is that going just that little bit faster uses a massive amount of extra fuel for little saving in time and a lot more stress.
I am referring to constant speeds set with cruise control where possible. It does of course depend on the type of journey and time available.
For me...... cruise control on......music on....,. Sit back and relax :):)
The journey takes a little longer and I spend less on diesel. It works out to be a 'free' bottle of wine every 100 miles :D
Mine is the Boxer with a 130 engine, I normally get approaching 37 on long steady runs mostly using cruise. Only time I've bettered that was after taking advice from a mech to run 3 tanks of BP Ultimate through it. 5p a litre more than straight BP and about 8p more than supermarkets. Got up to 39 to 40 which didn't in my view justify the extra expense. What I noticed on changing back was a loss of a smoke free, smooth run in all gears. I also thought the engine was a bit noisier but as I'm deaf as a doorpost that was probably aural make believe. I agree that a steady 50-60 does give much better mpg and so I keep to that even on motorways.
 
Dec 5, 2011
1,709
1,796
norfolk
Funster No
19,123
MH
Low profile C Class
Exp
Since 1997
After nearly 20000 miles in our Fiat 130hp van I have observed the following:

50 mph gives 43 mpg

60 mph gives 35 mpg

70 mph gives 28 mpg

Generally depending on how quiet/busy the roads are, I tend to cruise between 50 and 60. All these speeds are 'indicated' and in reality are about 4mph fast according to the GPS

My average overall is 38mpg

The 'shocker' is that going just that little bit faster uses a massive amount of extra fuel for little saving in time and a lot more stress.

I am referring to constant speeds set with cruise control where possible. It does of course depend on the type of journey and time available.

For me...... cruise control on......music on....,. Sit back and relax :):)

The journey takes a little longer and I spend less on diesel. It works out to be a 'free' bottle of wine every 100 miles :D
Are these figures from the computer readout, or actual figures from old fashioned neck to neck trials?
 
Apr 12, 2010
1,551
10,288
West Suffolk
Funster No
11,027
MH
Adria twin van conversion
Exp
since 2007
I generally set the cruise to 58 ish True speed 55mph. I did a sort of experiment last run out and took notice of the cars that whizzed past. When we turned onto the M25 off the M11 I recognised many of the fast cars. Then again when reaching the Dartford bridge the same cars were just in front again. This is caused by lorries overtaking at snails pace so everyone catches up.
Moral is theres no point in going faster than the lorries, so stick to 55 and save "loadsamoney"
Phil
 
Jan 25, 2013
712
9,451
Dorchester, Dorset, UK
Funster No
24,414
MH
Tribute T620
Exp
Since 1991
I was taught years ago that you have to double your speed to halve the time taken to travel the same distance - and the incremental savings over 50 mpg are hardly worth rushing for!
 
Feb 16, 2013
11,569
14,341
uttoxeter
Funster No
24,713
MH
ambulance conversion
Exp
50 years
Never done any keeping at one speed or anything else but check at every fill up and find, it makes no difference to mpg whether we do eighty down the motorway or toddle about at 40 its still between 25 and 28 never been out of that range, it does 100 miles to a quarter tank almost without fail and I fill as near as possible to 380 miles, never varies, iv been with my son and with a mate in their vans and they come up with various mpg according to their computer way above 30 to the gallon but they always end up putting as much or more diesel in when we fill up for the same distance
 

Bertie Bassett

Free Member
Jul 25, 2014
2,743
8,717
Funster No
32,543
MH
C Class
Exp
since 1988
Actual (although I have rounded down for the sake of brevity).

To my embarrassment I can count EVERY gallon that the van has ever used :eek:

No embarrassment there chocks, or should I say join the club? Nothing wrong with being 'cost aware/tight', I'm welsh and it's the only thing I've ever been an expert in.
 

Forestboy

LIFE MEMBER
Jul 31, 2007
5,118
8,373
Forest of Dean
Funster No
46
MH
A Class Hymer B694 tag
Exp
9
Never done any keeping at one speed or anything else but check at every fill up and find, it makes no difference to mpg whether we do eighty down the motorway or toddle about at 40 its still between 25 and 28 never been out of that range, it does 100 miles to a quarter tank almost without fail and I fill as near as possible to 380 miles, never varies, iv been with my son and with a mate in their vans and they come up with various mpg according to their computer way above 30 to the gallon but they always end up putting as much or more diesel in when we fill up for the same distance
Exactly the same here get 23mpg to 25mpg whether driving at 55mph or 65mph or 4250kgs 0r 5000kgs
makes virtually no difference. The only increase in mpg 2 or 3 is since I had the remap taken off that put it back up to 25mpg which it did before the remap.
 
Jan 19, 2014
3,794
11,614
south shields
Funster No
29,767
MH
Chausson 620 welcoome
Exp
since 1990
same sort of findings as op. if speed is kept to not much over 50 the range per tank full of fuel goes up dramatically . ie 550miles. if driven at 60+ then it drops to 450 or so.. that's distance driving.
ta andy
 
Aug 6, 2013
7,406
5,994
Kendal, Cumbria
Funster No
27,352
MH
A Class
Exp
since 1999
My difficulty is going fast enough to keep driving interesting & me awake. I don't find driving stressful at any sensible speed but I do find it difficult to go slow & stay alert. My Fiat 2.8 speedo dramatically over-reads (72 = 65). I use cruise control to run at a real 65 & around 22 - 24 mpg. I don't think I could go much slower. I too log every gallon (litre) I buy & do the calculation every couple of tank-fills or so.
 

OddSocks

Free Member
Apr 10, 2014
479
395
Cornwall
Funster No
30,940
MH
Coachbuilt
Exp
Newbie
I have been keeping an eye on my consumption too. (1990 Merc 208 D with Aftermarket turbo)

Guess what I discovered? Once I hit 60 mph (I rarely used to ever go that fast) something just 'lines up' and the thing flies! Up (very slight) hills and down dale! And you know what else? The tank full where I discovered this delivered the best MPG I have ever got from the van! Normal slow driving (55mph max) I get 21.5 on average. Driving at 60 I find I have to start backing off to avoid going even faster - 22.3 MPG!! Best ever - until........ I put 4 new Continental Vanco 2 tires on it last week. Next tank went up to 23.22! Blimey!

Will keep tabs on this once I have fixed my current problems.
 

AuldCodger

Free Member
Nov 25, 2009
284
126
?
Funster No
9,462
MH
?
Exp
?
Motorway just enough to keep out of the LGV guys who are working for a living, never use cruise as I would rather allow the the speed to drop off gradually on a steep incline as opposed to cruise giving it welly.
Back road speed depends on the scenery and other road users.
End result 33.2mpg average taken using onboard system and the old belt and braces full tank to full tank method.
Almost missed the essentials - Fiat Ducato Maxi 130
 

john kyte

Free Member
Dec 17, 2013
60
42
Salisbury
Funster No
29,403
MH
Ex ambulance
Exp
15
My difficulty is going fast enough to keep driving interesting & me awake. I don't find driving stressful at any sensible speed but I do find it difficult to go slow & stay alert. My Fiat 2.8 speedo dramatically over-reads (72 = 65). I use cruise control to run at a real 65 & around 22 - 24 mpg. I don't think I could go much slower. I too log every gallon (litre) I buy & do the calculation every couple of tank-fills or so.
Hello your speedo is then reading 9% fast----so your mileometer will also be 9% fast
So you need to consider this when working out your MPG
My speedo in an 89 Ford transit is 25% fast----confusing and probably illegal
This is the result of fitting a gearbox from a van with higher speed differential
 

PP Bear

LIFE MEMBER
Apr 5, 2013
3,777
9,462
UK
Funster No
25,395
MH
Coach Build
Exp
2012
And be a courteous driver - pull in and let people pass if they have been stuck behind you for a while. Why create aggro?
I'm a big believer in this. I'm still on my 7 week trip around the South and always pull in when required :)

Did it the other day for a delivery van, who promptly tooted and waved his appreciation :)

Gives us all a better name in the motoring world, which can't be a bad thing :)
 
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