1. Untitled Document

Fuel consumption - MPG

Discussion in 'TECH/MECH GENERAL' started by Philippft, Mar 24, 2008.

  1. Philippft

    Philippft Funster

    Feb 9, 2008
    Corby, Northants
    Not sure where to raise this question, so I thought I would raise it here and see how I get on.
    I've just calculated my fuel consumption for a Fiat 2.0 JTD engine pulling a 2.1/2 ton Motorhome, Mclouis Lagan 410 and I’m getting 23.8 MPG. This is based on motorway driving conditions with an average speed of 60 MPH and the rev counter around 2500 revs. I could easily increase my speed but I’m certain my fuel economy would suffer badly. I've thrashed it before over 50 miles or so, to find I was only getting 18 MPG.
    I have recently had the ECU Chipped which has improved the smoothness and pulling power quite considerably, especially when going up hills.

    My Motorhome is at the lower end of the market and compared to some of the monster we see on the road and I can’t help wondering how others find their fuel consumption. Our MH is only 3 years old so I think it will be reasonably fuel efficient and would be interested to know how other users get on. Oddly enough whenever I talk to dealers and the subject of fuel consumption is raised they appear to be a little evasive in their response.

    Anyway, I would be interested to know if I’m doing as well as or better than other owners. Are last years models giving good fuel returns, I’d be interested to know.

    All The best,
  2. stagman


    Sep 10, 2007
    West Wales
    Fitted a Steinbauer P box to mine, www. steinbauer.cc around 28mpg on my Fiat 2.8,far better pulling power especially on the hills,brilliant I think and would recommend it,
  3. Kell


    Sep 9, 2007
    Hi Philip
    My van is essentially designed as a working van. It's a '98' 2.8 turbo diesel Iveco panel van conversion. We weigh in at about 3.3 ton fully loaded for a trip.
    On a recent trip down through France and into Spain, mainly on motorway class roads, we averaged 27 mpg if we stayed at about 2500 rpm which gave us about 60 mph, but that dropped to 24 mpg if we did a lot of 70 mph (over 3000 rpm).
    Over the whole trip, including climbing up through Andorra from the Spanish side and a fair bit of 'sauntering' about off the major routes, we averaged around 25 mpg.
  4. drs


    Oct 13, 2007
    Ware, Hertfordshire
    Hi I have an Autoquest 140 with the peugot 2.2 100 engine this returns
    50mph 33mpg
    60mph 28mpg
    70mph 23mpg
    This vehicle has a trip computer fitted this has made no end of difference to the way I drive as I can now see my money disappearing out of the exhaust.
    My previous vehicle was a Swift Sundance 500 Fiat 1.9TD this returned 23mpg on average.
    Before that was a VW T25 1.9 petrol which returned 25mpg .
  5. pappajohn

    pappajohn Funster

    Aug 26, 2007
    scarborough, nth yorks
    my 2.8tdi returns around 26mpg at most 'normal' speeds. 50>60mpg A roads(always accelerating/decelerating), 70mph motorways (constant speed)

  6. RichardnGill


    Sep 22, 2007
    Our Hymer is on a Tranist 2.2. 130 BHP. It has never done less than 26MPG in over 4000 miles since new. If I keep below 60 Mph (2,100RPM) it can get 30MPG if its not windy.

  7. kands

    kands Read Only Funster

    Jul 20, 2007
    Our Fleetwood Flair weighs in at about 7 tonnes and has the Chevy 6.5 TD engine giving 190 BHP. We used to get about 15 MPG from our previous RV (measured over an extended trip in France last year) however this RV spends soooooooo much time in Travelworlds workshop that it is difficult to really know precise figures.
    I did check it on one trip that we managed to actually make and found that the consumption was about 6 MPG (even though the brakes were definately not binding, were they Simon???) but we cannot tell you about fuel consumption at speeds over 55 MPH because it will not go faster than that unless you go downhill.
    I fully intend to check this once we get the RV back from the Dark Star at Telford.

  8. Rainbow

    Rainbow Guest

    Our 2.8tdi, 20 foot, C-class Hymer does an average of 28mpg.

  9. vansmudge

    vansmudge Guest

    Engine re-mapping for fuel consumption improvement

    Hi Phililp,
    We have a Fiat 2.8 JTD and it is returning about 20mpg.
    I have been advised to have the engine re-mapped rather than waste the money buying one of the magnet thingies that are exhibited at MH shows.

    A correspondent on MH List told me the following:
    "One of the main reasons for poor fuel consumption on modern vehicles
    is due to the mapping in the vehicle ecu.Irrespective of where the
    vehicle is sold in the world market there is one map for example fiat
    2.8 jtd which is manufactured for the engine to run on the worst
    possible grade fuel like in some african countries.To make the engine
    run on poor garde fuel the engine is detuned.The best way to overcome
    this is to have the engine remapped,by doing this all the
    imperfections are removed from the map giving 3 benefits upto 35%
    more torque and bhp and approx 10% better fuel economy.
    espondent on MHList told me the following:"

    If any member can advise if they have had re-mapping carried out and the benefits I would be very gratefull.
  10. paulharrison

    paulharrison Read Only Funster

    Dec 4, 2007
    Hi Keith your Flair shoud do about 14-15 so there must a problem my winnie does more towing a car keeps my speed down to about 55mph, have a word with Dave west mids he could tune the engine
  11. Road Runner

    Road Runner Funster

    Jul 26, 2007
    South Wales
    My RV always tows and does around 7 to 8 mpg and it's a V8 7500cc ford engine and probably about 8 tons loaded like this.

    Since its been converted to LPG and is set very rich so poor mpg for the 1st thousand miles which it's now done will be re tuned and should get even better mpg on gas and it's already match the petrol figures so should improve.

    I cruise at 60 mpg to save being in the constant stream of lorry and hate being passed by some for miles on end so an extra 5 mph solves this and seems to be the engines sweet spot.
    Last edited: Mar 25, 2008
  12. Geo

    Geo Trader - Funster

    Jul 29, 2007
    I was extreamly impressed with my RVs MPG untill i made a fatal error

    I started the engine!!!!!!!!!:Rofl1:
    4 people like this.
  13. dazzer


    Jul 30, 2007
    In my house
    I get about 15ish at a steady 60ishmph but that drops to about 10-12 if we take it up to 90mph :Eeek:(yes it will do 90 but its a bit scary!!!:Doh:)

    Towing our 2 ton jeep on an a frame (lets not go there shall we :Rofl1:) we get about 12ish at a steady 60ish mph.

    Guess thats what you get from V10 Triton lugging just short of 5 tonnes around.

    To be honest I think the mpg is pretty good compared to the Euromobiles and all the comforts that you get with an RV. If i was getting less than 20mpg and living in a shoebox id be pretty cheesed off :Angry:

    However my opinion might change when we are all paying £2.00 per litre :Eeek::cry:
  14. Terry

    Terry Funster

    Dec 27, 2007
    South yorks
    Hi I posted this on the dark side

    now for my twopenerf,the only way to check your mileage is to brim the tank until you see the fuel-do your journey then brim again, then calculate your fuel usage.The use of computers do not give acurate figures !Motorways will make a big difference.
    example older vi6 2.9 tranny just running around 15/16 mpg on a run to the coast etc 19/20.5 mpg
    present iveco 2.8 td returned 30/31 mpg with running around-fitted a roof box now 26/27 mpg also knocked about 10 mph off top speed.Over the last 30 yrs I have drove / continue to drive all kinds of vans-work etc,and as a general average found the following driven more or less in the same maner
    petrol luton 16 /20 mpg
    diesil luton22/24 mpg
    petrol low profile /hi roof type 24/27 mpg
    diesil low profile/hi roof type 27/31 mpg
    the only exception to these figures I have found was trannys - petrols 22/24 mpg and diesils 27 mpg no matter how hard i drove them-slower or faster never seamed to make a difference having said that I found you had to thrash them to go anywhere at reasonable pace The other thing I see is that RVs all do 24 mpg :Rofl1::Rofl1::Rofl1::Rofl1:(when people are selling them ):thumb:
    I do have quite a heavy rt foot
  15. Philippft

    Philippft Funster

    Feb 9, 2008
    Corby, Northants
    Hi VanSudge,
    Thanks for your reply, my advice on engine remapping is to make sure you use a reputable firm and understand what you’re going to get in return.
    I paid a lot of money to get my engine mapped and the recommendation on who to use was by word of mouth, which in my view is the best kind.
    I was told that the real benefits of remapping are made by fleet company's who have lots of Trucks and can increase the power output from their engines considerably and save thousands of pounds as apposed to buying a larger engine. (If that makes sense!)

    The Chap I dealt with was great and gave it to me straight; I would get a substantial increase in Torque and would notice the improvement by way of increased smoothness and better pulling power, especially when going uphill. He reckons i would get between 2-4 miles a gallon better fuel economy for the same style of driving. So, if it's just fuel economy you’re looking for don’t expect a huge improvement.
    Basically what happened in my case was that a lap top was connected to my ECU through a port and copied the mapping on my ECH which was then emailed to Denmark where the map was re-written and sent back which was then downloaded onto my ECU and a check made to ensure it had been successfully embedded in the ECU. Job Done! A short drive confirmed everything had gone well.

    I've noticed a big increase in the pulling power and i suspect I could improve my MPG by reducing my speed a little further and improving my braking performance.
    Generally, I’m satisfied with what i have received and believe I will recover the money spent over the next few years.

    I’m grateful to all who have replied, so far and it looks like fuel consumption varies a lot but is averaging around 26 MPG or so with some getting better and some getting worse. However, 6 miles to the gallon is frightening, when I was in the Army many years ago I commanded a British Army main battle tank and I think we were getting better than that when on roads! At today’s prices I just could not afford to run a vehicle with that consumption.

    Anyway, thanks to one and all for your replies, it’s been interesting to say the least!

  16. les1

    les1 Guest


    I have been to the Wirrel caravan club site a round trip of 130 miles on the A41 and the M53. My vehicle is a Chausson welcome 50 2004 model It has the 2.2 jtd engine kept revs to around 2000rpm around 56 to 60 mph and achieved 32 mpg

  17. Road Runner

    Road Runner Funster

    Jul 26, 2007
    South Wales
    Why don't the manufacturers map/tune them to the best performance in the first place?:Confused::Confused:
    1 person likes this.
  18. dazzer


    Jul 30, 2007
    In my house
    cos that might cost them an extra 20p per vehicle:Eeek:
  19. RichardnGill


    Sep 22, 2007

    I think it is somethink to do with fuel grades. A standard engen will run on any old Derv, where as a mapped one will need a good standard of fuel.

  20. Gonewiththewind

    Gonewiththewind Funster

    Sep 13, 2007
    Do you mean that I couldn't run on my veg oil.:cry:


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