Accuracy of Fuel Consumption data via Trip Computer

Discussion in 'General Motoring' started by Mal from Oz, May 29, 2007.

  1. Mal from Oz

    Mal from Oz Guest

    Hi,
    Newbie to this group although been trolling for a few weeks. I've looked for
    a charter and/or FAQ but no luck so please accept apologies if this post is
    not appropriate here. I have a Volvo C30 but not sure if this group is for
    current or classic Volvos - I am sure you will let me know !

    Whilst is it obvious that fuel consumption is dependant on a number of
    variables, hitorically how reliable is the fuel consumption data provided by
    the trip computer in Volvos? When the computer indicates you have say,
    200km left in the tank, is this reasonably accurate ? Or are these devices
    simply a gimmick which should be ignored ?

    Cheers
    Mal
    Oz
     
    Mal from Oz, May 29, 2007
    #1
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  2. Mal from Oz

    Joerg Lorenz Guest

    I can only speak for the 850 (GLT 2.5 and T5)/V70 (T5 and D5) makes.
    My experience with the gasoline powered Volvos shows an accuracy
    compared to the manual calculation of 2-3 % deviation. IMHO this is
    very accurate. What I found out is that the fuel tank volume indicated
    by the manual is very conservative. My new Volvo V70 D5 (185 hp) has
    an indicated fuel capacity of 72 litres. I once refueled more than 75
    litres.

    The fuel consumption indicated on the computer on the same Volvo V70
    D5 is roughly 10 % lower than the real value which I consider as very
    inaccurate.
    Joerg
     
    Joerg Lorenz, May 29, 2007
    #2
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  3. Mal from Oz

    Mal from Oz Guest

    Thanks for that Joerg - so apart from checking it myself against an empty
    tank - are you suggesting that the computers in the petrol engines appear to
    be more reliable that their diesel counterparts ?

    Cheers
    Mal
    Oz
     
    Mal from Oz, May 29, 2007
    #3
  4. Mal from Oz

    Joerg Lorenz Guest

    In my individual case that is my experience. My wife switched from a
    gasoline powered Renault Scenic to the new 2.0 Diesel (150 hp/340 NM)
    with 6 Gear-Automatic. In this particular case the trip computer on
    the diesel is more accurate (1-2 % deviation) than the one on the 2.0
    gasoline 4 Gear-Automatic was (3-4%).
    Joerg
     
    Joerg Lorenz, May 29, 2007
    #4
  5. Mal from Oz

    Roadie Guest

    The fuel consumption computers in Volvo and other cars are reasonably
    accurate when measuring things like average MPG for an entire tank of
    gasoline or spot MPG. The
    It's a reasonably accurate but not precise measure that assumes your
    driving habits won't change. It is not precise on the cars I'm
    familiar with when compared to the analog fuel gauge. The car will
    appear to use somewhat less fuel for the first half tank of gas
    compared to the second half. I have to assume this anomaly has to do
    with a gasoline tank that is irregular in shape.
    No, unlike rain sensing wipers they actually do something useful.
     
    Roadie, May 29, 2007
    #5
  6. Mal from Oz

    Marvin Guest

    The estimate is based on the recent rate of fuel
    consumption. If, for example, you have been driving on
    limited access highways, and then go onto city roads, the
    estimate will be way off.
     
    Marvin, May 29, 2007
    #6
  7. Mal from Oz

    Mal from Oz Guest

    Thanks all for the feedback re the the fuel data.

    On the wipers tho, odd you should say this - this is the first car I have
    had with rain sensing wipers and am impressed (so far). We had plenty of
    rain on the weekend in varying degrees, spits, showers and heavy rain. I was
    actually very impressed with them. Even to the point where they adjusted
    their speed and sweep rate depending on how hard it was raining. I'm don't
    know whether this is a standard feature with rain sensing wipers, but the
    C30 has a sensitivity adjustment on the steering column. I had this set at
    about 50% and I found the system very effective.

    Cheers
    Mal
    Oz
     
    Mal from Oz, May 30, 2007
    #7
  8. Mal from Oz

    Roadie Guest

    They work well maybe 70% of the time. Other times the wiper will
    begin speeding across the glasss under the slightest of mist or it
    will operate at a very slow speed in a downpour. I'm told by other
    owners that their experience is similar. To be honest it really
    offers no improvement on simply switching the wipers on as needed.
     
    Roadie, May 30, 2007
    #8
  9. Mal from Oz

    Mal from Oz Guest

    Ok, I'll definitely keep an eye on their behaviour then. Concur that turning
    the wipers on/off manually is no real drama - but I was impressed by the
    need not to continually adjust the speed every time the rain changes - and
    it does that here a lot in a short space of time. You find yourself
    continually changing from intermittent, slow, fast, back to slow etc

    I did find that with the adjustment knob set to 100% that the wipers didn't
    stop quickly when the rain stopped. Thats why I set the dial to half-way.
    After that I found them 100% effective. Caveat: this was the first weekend
    I had to use them and the really heavy rain is yet to come. Maybe I'll
    report back at the end of winter to see if I am still as impressed !

    But appreciate the heads up.

    Cheers
    Mal
    Oz
     
    Mal from Oz, May 31, 2007
    #9
  10. Mal from Oz

    Roadie Guest

    I may be overstating it somewhat, because most of the time they
    perform as you describe by speeding up and slowing down ad the
    rainfall changes. Some of the time, after the wipers have been in
    rain sensing mode for a while they behave erratically as I described.
    It's as though the memory chip overflows with rain measurement data
    and goes wacky. Shutting the wipers off for a moment and restarting
    seems to cure the problem. Dealer says this is common and a family
    member who owns a Chevy suburban with those wipers reports the same
    experience.
     
    Roadie, May 31, 2007
    #10
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