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What fuel economy do you get?

Discussion in 'Diesel forum' started by necroeire, Aug 28, 2006.

  1. stuart_75
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    stuart_75 Member

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    [Jul 5, 2008]
    Ive got a 2003 1.9 130 sport quattro avant.

    Being really careful (55-60mph on motorways, no air con, coasting whenever going downhill) I managed 42mpg.
    #41
  2. M7R
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    M7R Type Approval Engineer,

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    [Sep 15, 2008]
    Not true, the ECU does know whats happening when a proper tuning box if fitted - not a resistor in a box one that tricks the temp sender - this is most apparent if you watch the instant mpg, as with the box this is normaly higher, but if you boot it it will drop lower than before. I ran a box on my 1.9 115bhp PD for 8 months or so and I did get a slight improvment in ecconomy, but you have to think of it more as free power, as you get a extra 25+bhp with no drop in ecconomy.


    Ive just got my 140bhp A4 and from the 230 miles ive done this weekend it seems ill be getting 600 to 650 miles per tank, so thats roughly 40-43 to the gallon...tbh im a bit miffed by that, but is due a servce soon so im hoping that will improve things, and this has been mostly A and motorway work crusing at 70mph, and its not like the engines tight as its got 91k on the clock now.

    #42
  3. jameshughes1974
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    jameshughes1974 Member

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    [Sep 18, 2008]
    Have just read my own message and to be clear I do mean tuning boxes outside of the ecu.

    I know that a chip change(remap) in the ecu might leave the DIS working correctly but am not too sure about this to give an answer.

    But any tuning box regardless of how much you paid for it (and thinking that paying more means you are getting a significantly better one) is modifying a signal external to the ecu.
    The ecu is blind to this and does its sums based on a "map/calculation" on the understanding that all the readings it gets to do this sum are coming from non modified parts/sensors within their normal operating range.

    Even if the said box didnt modify say the quantity of fuel just its timing you would still be invalid because any electronic component has a accuracy tolerance on it and this tolerance adds itself to the signal chain. eg most cheap capacitors could vary +20% from what they say on the label

    Clearly by modifying the signals to and from the ecu the DIS mpg reading will be made invalid.

    Dont get me wrong thats not to say getting your car chipped\boxed wont get you more MPG - it should get slightly more but the best way to find out is to do your own sum.
    Even an un modified car should be checked against the DIS manualy - you may be suprised to see a difference in some cases.

    Another example of this is when people change the wheels on the cars - usally to much bigger ones - the speedo is no longer calibrated and indicates the car is going slower than it actualy is.

    Your car may be that close that the DIS is more or less correct- or perhaps adding the box has made it correct!

    Regards your MPG - yep its a bit disapointing that each generation of A4's seems to be doing less MPG than the previous.
    I have a B5 110 TDI which is chipped to 143 doing 51-52 MPG normal/fast driving.
    I moly coddled one of the company A4's with a PD100 engine in it and couldnt get the DIS past 50- perhaps it needs calibrating
    #43
  4. Macduff
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    Macduff Member

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    [Sep 18, 2008]
    Even then mine is typically 3-4 mpg over optimistic.
    #44
  5. quattrojames
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    quattrojames Moderator Staff Member Moderator

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    [Sep 18, 2008]
    I'm surprised at that, I have a 2003 2.5TDi quattro avant, and driving carefully, ie less than 2500 rpm, and max 7-mph I can get spot on 40mpg. But I have never had to coast downhill or turm my aircon off!!

    I know the quattro typically sucks 5-10mpg but averaging 42 doesn't seem great to me. Depends on the roads you use I suppose ....
    #45
  6. Caesium
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    Caesium My BM is fixed!

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    [Sep 19, 2008]
    Sounds like Maidstone to Guildford....
    #46
  7. Batt284
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    Batt284 Member

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    [Feb 9, 2009]
    A3 2.0 TDI 140, get around 45 mpg driving reasonably with mix of motorway and town driving. In my case it really does not seem possible to get over 50 mpg on the motorway, even at 70 mph.

    From reading other peoples comments on this subject, I have come to the conclusion that the 1.9 engine is quite a bit more economical than the 2.0 litre. Still, the economy is a lot better than my previous car!
    #47
  8. nick-A6
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    nick-A6 Member

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    [Feb 10, 2009]
    Same here i have a 98 v6 2.5TDI manual and im averaging 26 to 34 with mainly town driving, is there something up with mine?
    #48
  9. APL TDi
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    APL TDi Member

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    [Feb 11, 2009]
    My economy is being ruined by two massive hills I have to drive up every day!

    I used to get about 48 when I went to pompy and back (from guildford). But now I get 44 when I go to Petersfield and back. Grrr :motz:
    #49
  10. dieselfitter251
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    dieselfitter251 Blow ma own trumpet?

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    [Feb 11, 2009]
    Aye, around 46-48 this time of year. During the summer months mpg happily wanders up to 50-52.... wierd eh?
    #50
  11. TorqueTerrorist
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    TorqueTerrorist Audi A4 S-line Avant 2.0T FSI

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    [Mar 25, 2009]
    I have a 'Tunit box' that claims better performance and increased fuel economy.
    100% the truth!
    We was getting around 600miles per tank and can get around 700miles per tank now, well when the missus drives it lol. When you give it a bootful it drinks like f*ck now though but so worth it for the money (£469)
    Although now i wish id had it re-mapped as i want to add further mods but such is life i guess. Will just sell the 'Tunit' when i get mapped!
    #51

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