Best Fuel Consumption for 103/125kw TDi's on longish trips

[passatpout]

I drove from Melbourne to Newcastle last Sunday, sitting on 120 (speedo) with the air-con on most of the way. I filled up when I arrived in Newcastle, a tank distance of 1045km and consumption of 60.04 litres (average of 5.75l/100km). It was only because I had to go back to Sydney on Monday that I refuelled, but looking at the numbers now I easily would have made that, so could have achieved around 1200km (+/- 20km) on the tank - at that consumption rate, it would have used 69 litres, plus the southbound trip into Sydney is marginally easier on consumption than the northbound.

Since then, with another couple of trips around Sydney and the Blue Mountains, according to the car I've travelled around 1500km and used 5.8l/100km average.

Cumulative average for it since I picked it up (as at last fill up): 277.54 litres and 4,177km, an average of 6.64l/100km, with a reasonable mix of around town Melbourne/Sydney/Geelong/Newcastle, freeways and highway driving, flat ground and mountains. I've also not been too light on the throttle and taken full advantage of its performance a few times, as some Falcodores have found out to their chagrin.

In Melbourne, from out north west (near Sunbury) to Altona, Werribee and Geelong I regularly get around 5.1 on the way there, and about 5.6 on the way back (the hills around Melton Hwy past Calder Park really throw it out).

I'll be heading back to Melbourne from Newcastle tomorrow - not sure whether to stick on 110 indicated to save a bit on fuel, or stay on 120 and do the trip that bit faster. It'll probably be the faster one.. I need to get to work on Monday and won't be able to leave Newcastle until about 10am..

[richdave]

my TDI 125kw is getting a long term average of 7.47 lt/100km based on 16K of mostly city driving.... calculated based on actual fuel into car over 9 months. My best "displayed" value has been 5.8 lt/100km on a Casltemaine run IIRC.

I am concerned about the apparent inaccuracy of the speedo! I usually "stick" to the limit or maybe a couple km over... is the lame speedo the reason why so many behind me seem to get pissed off at me driving at "100" in a 100 zone?

[drbass]

Hi passatpout,

Were you on Motor Torque last Thursday night?

The odometer in my car is spot-on (measured a few times using km markers along various highways/freeways).

HOWEVER, the speedo is definitely out. According to my GPS (Garmin Nuvi), at 107 speedo (set via cruise control) I'm actually sitting on 102. 117 on the speedo correlate to 111 real life. So, richdave, you're probaby doing only around 95 when your speedo indicates 100.

Best real-life tank (filled to the brim) gave me 5.9l/100 (computer gave me 5.6), 66.6l for a total of 1129 km (incl. Melb-Syd via Gippsland/Canberra, some Sydney driving, then down the coast to Woonona). I find that the computer is more accurate when doing longer trips, and gets worse when there's many short trips - about 10% optimistic is what it's been up to.

Seeya,
Michael

[Transporter]

my TDI 125kw is getting a long term average of 7.47 lt/100km based on 16K of mostly city driving.... calculated based on actual fuel into car over 9 months. My best "displayed" value has been 5.8 lt/100km on a Casltemaine run IIRC.

I am concerned about the apparent inaccuracy of the speedo! I usually "stick" to the limit or maybe a couple km over... is the lame speedo the reason why so many behind me seem to get pissed off at me driving at "100" in a 100 zone?

Their speedo would be mostly similar to yours but they knowingly drive 10km over speed limit and hoping they get away with it. They expect that everybody else will be doing the same and if not they are pissed off.
Inbuilt inaccuracy in VW cars is actually favor which is saving normal motorist a lot of money since it is easy to go 10km over the speed limit and takes only a split second to get clocked by speed camera.

I used my GPS to check what the difference was:
Golf 67km/h GPS measured 60km/h
T5 64kmh GPS 60km/h
Touareg 62km/h GPS 60km/h

The reason for that inaccuracy is difference in tyre diameter (brand new/almost worn out)

[passatpout]

Hi passatpout,

Were you on Motor Torque last Thursday night?

Nope, never heard of it.

The odometer in my car is spot-on (measured a few times using km markers along various highways/freeways).

Mine was about 100-150m short over the 5km odo distances marked out in NSW. Bit hard to tell exactly, with a digital trip meter and the position of the sign.

HOWEVER, the speedo is definitely out. According to my GPS (Garmin Nuvi), at 107 speedo (set via cruise control) I'm actually sitting on 102. 117 on the speedo correlate to 111 real life. So, richdave, you're probaby doing only around 95 when your speedo indicates 100.

Interestingly, I went under 3 NSW speed warning signs today. The first was in a 90km/h zone, and the cruise was set at 95 - no warning for me, yet people who were moving marginally faster were getting it. The other 2 were both in 100km/h zones, with cruise set on 110km/h exactly, and no warning for me (the first time round, it flashed up the warning for a white van which then proceeded to tailgate me).

Best real-life tank (filled to the brim) gave me 5.9l/100 (computer gave me 5.6), 66.6l for a total of 1129 km (incl. Melb-Syd via Gippsland/Canberra, some Sydney driving, then down the coast to Woonona). I find that the computer is more accurate when doing longer trips, and gets worse when there's many short trips - about 10% optimistic is what it's been up to.

Seeya,
Michael

I've noticed that tank-to-tank, the car figures and the actuals are pretty close - for this trip, the car was saying 5.8l/100km when I filled up in Newcastle, and the spreadsheet I'm tracking the numbers by worked it out to be 5.75km.

This has me wondering though. From what I've read, we all pretty much agree that speedos seem to be out by about 6-8% (not quite enough to complain about ADR compliance, etc), but we have differing accounts about the accuracy of other info from the car - consumption figures, odos, etc.

Now to get the joy of driving back to Melbourne from Newcastle tomorrow, into this almost-cyclone that's parked itself over the eastern states..

Cheers,
AP

[richdave]

The reason for that inaccuracy is difference in tyre diameter (brand new/almost worn out)

Doesn't the inaccuracy get worse with more the tyres wear?

[passatpout]

Well, after my trip north last week, I covered 2971km, and used a total of 179.06 litres of diesel, an average of 6.024l/100km. Rough trip was:
Melbourne to Newcastle
Newcastle to Hornsby
Hornsby to Winmalee
Winmalee to Newcastle
Newcastle to Melbourne

With about another 200km or so of local driving around Sydney, Newcastle, etc.