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TDI 170 PD MPG - DIS / MPG accuracy? (pessimistic)

Discussion in 'A3/S3/Sportback (8P Chassis)' started by c_w, Dec 8, 2010.

  1. c_w
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    c_w Active Member

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    Had a 170PD for a few months now and was kind of shocked at the mpg of it, especially urban. Very steady motorway driving (with traffic flow but no more than 70) would return high 40s, maybe 50 dead at a push). Coming from a TDI 140 is was a bit of shock where that would return (according to the DIS) amazing figures even for urban/mixed driving. The 170 shows mid 20s if you do a short urban trip vs over around 40 in the 140 (all DIS figures).

    However [in the 170] I put in £25 (20litres) when the tank range said 5miles and it did 220miles which at a rough calc is actually about 50.5mpg, yet the computer said around 46mpg average. This got me thinking if the DIS isn't accurate (pessimistic) so waited until I was doing a longer journey and calculate it more accurate by filling the tank and refilling afterwards.

    So I've just brimmed the car today, reset the trip (the one in the speedo dial), and also Computer 1 then drove to central Birmingham and back from Manchester which included some urban driving onto and after the motorway either end. Where possible I set the cruise at 70, there was an accident southbound which slowed progress, and then an accident northbound too...which meant I was in crawling traffic a few times and then used an alternate route back home (A34 which is a-road with a bit stop start).

    Getting back I went straight back to the petrol station (188 miles), brimmed it again and it used 15litres exactly; that's 57mpg(!). The DIS showed 49.5mpg average. The fuel level dropped to between full and 3/4 (so used 1/8th according to the gauge).

    I'm wondering if the 170 DIS for some reason is just pesimistic, and maybe the 140 DIS is a bit optimistic?? Either way I'm pleased with the results.

    It may be worth mentioned the car has the DPF delete BUT the DIS figures were the same before for mpg same kind of driving.
    Last edited: Dec 8, 2010
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  2. slade777
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    slade777 Member

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    Atleast your getting better than you thought and not the other way!! Maybe my DIS is optimistic on my 140.

    [​IMG]

    This was after a 30 mile SLOW SLOW boring drive on B roads at about 50mph followed by a short stint through a town with minimal traffic.
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  3. c_w
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    c_w Active Member

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    75mpg does sound unfeasibly high! I think the only way to know for sure is to do the brim to brim method.
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  4. Vertigo1
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    Vertigo1 Well-Known Member

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    Interesting. Was shocked at the economy of my PD170 after I came from a PD140 but never thought to actually double-check what the DIS was reporting. Will be keen to see how the new CR170 fares in comparison and will definitely do some actual consumption tests of my own to compare with the DIS.

    BTW, regards cruise, when I had this on my PD140, I found the economy was worse using it than holding the speed on my own. I think the cruise is too fixated on maintaining the exact speed you've set and this can harm economy compared to doing it yourself and letting it wander a bit.
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  5. PilotAudi
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    PilotAudi New Member

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    When do you folks believe the PD170 became a CR170... I am hearing conflicting stories!
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  6. pi quattro
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    pi quattro Member

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    I too have had a 170 and a 140, both quattro. In the 140 I could brim it and it would take ages for the fuel tank needle to move. In the 170 it move after only a short while? Seriously I could drive over 100 miles in 140 before any movement. Seems like different cars have maybe different calibrations?

    How do I tell if current 170 is pd or cr? It is noticeably quieter than 140
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  7. c_w
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    c_w Active Member

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    The PD170 is noticeable quieter than the PD140. On an 07 it will be the PD170, I think it was 08-on (or maybe 58?) that is the CR170.

    There may be differences in gauge/tank calibration, probably best to do the manual calc method to see. Yesterday mine didn't move off full for about 90miles or so, much like the 140 which would stay on "full" for ages.
    Last edited: Dec 9, 2010
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  8. c_w
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    c_w Active Member

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    Yea I think you're right, it's eager when it comes to hills etc and sometimes overcompensates a little, but for that small difference I would rather sit back and let the cruise do the work! it makes a longer/boring journey much easier IMO.
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  9. Eeef
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    Eeef Lord of War

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    I've also gone from a 140 to a 170 (but in a Golf) and the DIS MPG change was huge, but I think the data used for the 170 is 'revised' to that of the 140. Now I use www.fuelly.com to track my REAL mpg.

    [​IMG]
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  10. crunchie
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    crunchie Member

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    I can get an average of 60 mpg on a long run in my 140. I think Audi programme them to show less mpg after a year or so in the hope that you might take it in for a service lol
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  11. piotrtdi
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    piotrtdi 2.0 TDi CR 170 Sportback BE

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    Last edited: Dec 9, 2010
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  12. smudge_don
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    smudge_don Active Member

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    I too went from a 140 to a 170, but the 140 was also manual whereas the 170 was DSG

    I noticed a dip in fuel economy on a motorway run from about 48-50 in the 140 to 38-40 on the 170

    I once got 786miles from 1 tank in the 140, that was ALL motorway driving at 50-60mph

    I was lucky to get 400 to a tank in the 170
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  13. Stratts
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    Stratts Member

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    This goes a bit aginst the logic of cruise control. Most 'experts' suggest that cruise is far better at holding a constant speed compared to the driver, who inevitably will move his/her foot slightly and therefore be unable to keep the same speed. This makes cruise much more economical over a distance in the right circumstances.

    Where cruise falls down is if you want to accelerate or climb a hill, as it will always use full throttle regardless of what gear you are in. My understanding was therefore use cruise if you want to maintain a steady speed on a semi-flat route (e.g. roadworks) but otherwise turn it off.
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  14. PilotAudi
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    PilotAudi New Member

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    Our recently gone 170 Quattro was a 2008 (08) pre facelift with side indicators in the wings rather than mirrors. That was a noisier motor than the current 170 so I think you may be right although our 170 was noticably quieter than our near neighbours same age (57 Reg) 140 bhp version. The latest SS seem even quieter the 1.6Tdi Loaner is nearly as quiet as our 3.0Tdi !
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  15. c_w
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    c_w Active Member

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    Yea think with the new CR Audi have finally moved into the 21st century where BMW have been with their quiet 2.0TD since '99!!
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  16. c_w
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    c_w Active Member

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    I'm not quite sure I follow - I do but not sure what goes against CC? I would agree CC maintains speed better but it works tirelessly to maintain that set speed despite incline whereas as a "driver" you could lift a little and slow on inclines which will return better mpg.
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  17. Vertigo1
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    Vertigo1 Well-Known Member

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    On an 07 car, it'll be the PD - the PD170 was only introduced with the 56-plate cars.

    I concur that the PD170 is a lot quieter/smoother than the PD140 but the CR170 is an even bigger leap - I'm staggered how quiet and smooth it is compared to the PD170.
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  18. PilotAudi
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    PilotAudi New Member

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    Maybe but IMHO BMW are tasteless **** in comparison...:sadlike: wouldn't dare post that comment on a BMW Forum!!! ;-)
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  19. c_w
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    c_w Active Member

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    1-Series hatch is a bit odd, but the Coupe is great IMO, and the M Sport 3s are very nice with a very smoooooth drivetrain.
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  20. PilotAudi
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    PilotAudi New Member

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    Yeh maybe of you like Tat.

    BMW interiors are soooo plastic and naff. New GT is a huge improvement. Tonka toy plastic may be acceptable in a Mini but not a BMW. I think BMW lost the plot in about 1983!
    The modern BMW image is poor, the interior quality poor, the design (especially Bangle) is dubious... sorry asan overall package Audi is in a completely different league, although I do prefer BMW RWD handling to FWD ... hence we prefer Quattro which is awesome.
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