Mpg.. Staggering Difference Found

Jaws

Jaws

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Location
Thetford Norfolk
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4,189
MH
C class, Chieftain
Exp
since 2006 ( I think ! )
Today, as we were in absolutely no hurry and the road fairly flat with virtually no stops for a 100 miles, I tried an experiment
The van has consistently returned 20 to 21 mpg ( used to be 18 to 19 mpg before I fitted a Torquing of Diesel control box ) but as is my way I wanted better mpg.. It being only a 2.3 ltr fitted in a 5t+ Autotrail I will be honest and did not really expect any decent results no matter what..

However...................

Today I dropped the cruise control from 55 mph ( on the GPS ) to 52 mph

To say the results were shocking is an understatement
Over the 109 trip the MPG shot right up to JUST over 26mpg

That is an extra 25% for heavens sake.. and all effectively for free and for the sake of 3 MPH

Guess what speed we will be travelling at hence forth !!
 
As I'm sure you're aware John wind resistance is the biggest killer of fuel consumption and it increases by the square of the speed. It actually doesn't make much difference till you get above 50mph but then it increases massively. Our Iveco will do 28MPG cruising at 50MPH without the trailer but that drops to 25-26 at 56mph, at 60mph its down to 22-24mpg.

D.
 
Worth experiment.
Ours returns quieter journey and more mpg at 55 compared 60. Cruise makes a difference but I also let it 'run' down hills

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Exactly why i sit at 52mph at 2000rpm and get around 8mpg (lpg)

60mpg sees it down to around 6mpg.

70mph would just not be viable.

Cruise control makes a difference in favour but never on hills....changes down to 3rd and the revs go up to over 4000rpm so cruise gets overridden at the bottom of any hill...even on motorways.
 
Even slippery aerodynamic cars need massive power to get the really high top speeds so our bricks on wheels stand no chance (n)
 
Mine at 100 kph does 20. At 80 kph it does 27.
Remarkable difference.
 
Over the 109 trip the MPG shot right up to JUST over 26mpg

That is an extra 25% for heavens sake.. and all effectively for free and for the sake of 3 MPH

Guess what speed we will be travelling at hence forth !![/QUOTE]

And the cost saving only took approximately 10 minutes longer
 
I get 30mpg from my van if I stick to 50 on single carriagways and 60 on motorways.

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pappajohn said:
Exactly why i sit at 52mph at 2000rpm and get around 8mpg
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MY GOD!! This does 3 to the gallon! :Eeek::Eeek::Eeek:

Handler (1).jpg
 
Our camper van averages 28mpg - max 36mog when cruising at 56mph and down to 18 when at 80mph (130kmh) on French autoroutes.
 
Badknee said:
Even slippery aerodynamic cars need massive power to get the really high top speeds so our bricks on wheels stand no chance (n)
Click to expand...
Exactly......

James May.....Buggatti Vyron.....top gear...VW test track.

To get to top speed of 250mph it took all 1001 horses the engine could muster......and that is one slippery car.
 
pappajohn said:
Exactly......

James May.....Buggatti Vyron.....top gear...VW test track.

To get to top speed of 250mph it took all 1001 horses the engine could muster......and that is one slippery car.
Click to expand...
Exactly PapaJohn..
It takes more energy to push that big brick through a mass of air (motorhome, not Vyron!) . Proportionally that extra few miles per hour takes a disproportionate amount of energy that it took to wind it up to a lesser speed.
Anyway, if I'm in a rush pull out the ZZR !
 
Ours hasn't even got 500 miles on the clock yet.
We are enjoying watching the computerised Average miles per gallon creep up and up. It's at 29.7 at the moment.
We've only been to Whitby goth , a couple of months ago, and Newark this weekend in Pug so far.
We've been told it will take at least 1500 , 2000 miles before we are getting proper average miles per gallon.
 
pappajohn said:
Yeah....but that weighs 32 tonnes.

And imagine how many gallons to the mile were it a petrol engine.
Click to expand...
It weighs 52 tons John, and yes, it does have a petrol engine......Well, Multifuel. :)

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When I'm not in a hurry I always drive in the rpm range where the engines achieves its maximum torque.
On a 2.3 fiat its at 1800-2000 rpm. I think you will find in that rpm range you will achieve the best MPG.
Use the torque Luke!
 
Last but one trip to Brittany and back returned around 26 mpg at speeds up to 110kmh but generally kept to 100. Last trip I set the cruise control at 90kmh and returned 31 mpg.
That's a lot of spare fuel.
Allan
 
best mpg story ive heard was the late bob monkhouse
his neighbour bought a new super economical car and was bragging about it
so bob for the first month put a couple of gallons a week into the neighbours car without him knowing,his neighbour was amazed at the wonderful car he had bought and told every one
after the month was up bob then started to reclaim his petrol by syphoning it back out every night
 
30000 miles

37 mpg average

44 on the motorway

always cruise at 55 indicated with cruise control on

:D:D:D:D:D:D
 
mitzimad said:
best mpg story ive heard was the late bob monkhouse
his neighbour bought a new super economical car and was bragging about it
so bob for the first month put a couple of gallons a week into the neighbours car without him knowing,his neighbour was amazed at the wonderful car he had bought and told every one
after the month was up bob then started to reclaim his petrol by syphoning it back out every night
Click to expand...

Not sure about the "Bob Monkhouse" connection, but this adding and then syphoning petrol secretly from a neighbour's car featured in this film.

http://community.cartalk.com/discussion/2289320/adding-gas-to-increase-mpg-joke

"A prankster wrote in to Click and Clack to say that he and his buddies had added gas to a co-worker's FIAT to hear him brag about the fantastic mileage he was getting. Then they started siphoning gas out and his MPG plumeted.

That was a partial plot line in a 1972 movie "Pete and Tillie" starring Carol Burnett and the deceased Walter Matthau. Only the car was an orange VW IIRC."

JJ :cool:

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mitzimad said:
best mpg story ive heard was the late bob monkhouse
his neighbour bought a new super economical car and was bragging about it
so bob for the first month put a couple of gallons a week into the neighbours car without him knowing,his neighbour was amazed at the wonderful car he had bought and told every one
after the month was up bob then started to reclaim his petrol by syphoning it back out every night
Click to expand...
And of course, that wasnt a typical corny monkhouse gag.
 
pappajohn said:
Just to add some realism to the thread......i get 73mpg from my 10ltr 55 ton bus and i only drive uphill with a head wind and the handbrake on.

About as realistic as some of the imaginary mileage quotes going to be posted on this thread.
Click to expand...

Which ones are imaginary?
 
A 25% improvement of mpg for a 3 mph reduction in speed is implausible I think. Was there a strong tailwind? The trial needs to be done over a much longer period I think to get a reliable result. The mpg will be better of course for the slightly reduced speed but that much improvement doesn't compute unless there is some other factor involved other than the change in speed. I'm not doubting the mpg figure isn't correct, only that the speed reduction was the sole reason. :)
 
Ralph-n-Bev said:
Ours hasn't even got 500 miles on the clock yet.
We are enjoying watching the computerised Average miles per gallon creep up and up. It's at 29.7 at the moment.
We've only been to Whitby goth , a couple of months ago, and Newark this weekend in Pug so far.
We've been told it will take at least 1500 , 2000 miles before we are getting proper average miles per gallon.
Click to expand...

We have 1200 miles on our Fiat 2.3l with 150bhp and the MPG is starting to get better but nowhere near 29.7. Average is sitting at approx 24.6 right now. I use the sat nav to gauge speed and sit at the speed limits +/- 1mph. Engine turns at a constant 2000 rpm and very seldom shifts from that even going up hill; a steady climb rather than steep where it will move up a bit. If I average 25mph then I am good to go, anything above is a bonus (y).

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