CC TDI - Fuel economy

[hadrami]

But was the tank the same capacity.

Doing consumption by tankful is fraught with errors and anomalies. Eg Our Polo will do nearly 900 k per tank on a trip.

The Landcruiser I had would do over 1000k on a tank The Polo has a 44 L tank and gets 5.1 K per L The Cruiser has a 145L tank and gets about 11k per L So going on "by the tankful" the Cruiser is as economical as the Polo. NOT.

The only way to check consumption without a special tank is to fill it till you can see the level do the trip and fill it at the same pump to the same level.

Then I will believe your figures. Saying I went from A to B and still had ABOUT half a tank means nothing as gauges can be unreliable to say the least.

One car I had would read 3/4 full for hours and then all of a sudden it was on 1/4. Was a bit disconcerting if you didnt know about it.

There has been some unrealistic figures posted about consumption being better than what the manufacturers advertise.

As their figures are normally done under controlled conditions at optimum performance to achieve them I wouldnt think they could be replicated in normal urban driving.
I would sooner be realistic than optimistic and fool myself into something that may not be correct.

Yes, they are both 70 litres.

But obviously the Aurion was a V6 petrol with 200kw which the wife didn't need, hence our decision to go for a better car in all aspects (- power I guess) but in a diesel.

[safetyman]

The method I've always used is seeing the amount that I've just put into the "empty" tank and dividing that by the kilometers driven since the last fill.

Always gives me a pretty accurate rate of consumption.

[Hillbilly]

The method I've always used is seeing the amount that I've just put into the "empty" tank and dividing that by the kilometers driven since the last fill.

Always gives me a pretty accurate rate of consumption.

With the difference in accuracy of petrol pumps I wouldnt use that method.

For instance my cruiser had a 36 L aux tank and at Hervey Bay one fill it took 41 litres I made a complaint about the accuracy of the pump as had never ever managed that amount in it before or since. The tanks have separate fillers and dont cross feed.

I use the same pump at the same servo and always fill it till I can see it when doing consumption tests.

[safetyman]

Agreed regarding the accuracy of pumps. Could also be why I've managed to squeeze 70L into the tank a few times.....

And I do always use the same petrol station and pump.

[kaanage]

The ideal way to run a diesel is get it hot and keep it hot. Whilst 400k a week is ok, if you do it in 10 40km runs its not.

I guess that's why I average only about 5.0 l/100km (calculated from fill up vs odometer) in suburban traffic doing sub 20km runs (in my 1.9 TDi Polo)

BTW This thread would have been much better started in the diesel forum

[Eaglen00b]

Wow, one would hope that Fair Trading would be clamping down on uncalibrated pumps if pump accuracy is that bad at gas stations. Extrapolated to the number of motorists who would use these suspect pumps, that's hundreds of thousands of dollars possibly millions of dollars being billed for fuel not delivered.

[ralphk]

mostly freeway I am getting 5.8-6 (actual not computer calculated)

[GippsCC]

I just used my very first tank of diesel in my CC, from which I got 1,105 kms. My yellow fuel warning light was on by that time, but the red light warning had yet to appear, so quite possible I could have got near 1,200kms.

What is impressive about this is that my driving is a mixture of frequent short trips, interspersed with occasional 2 hr drives, and given I was running a new engine in, consumption should even improve.

Not bad at all.

[brad]

If you are getting 1100km out of your first tank then you aren't running in the engine.

I don't subscribe to the "drive it like you stole it" theory but you do need to get some turbo pressure in behind the rings so that the high spots are worn off the cross-hatching in the bores.

Personally, I wouldn't allow the gearbox into 6th gear for the first 3,000km.

[Eaglen00b]

That'd mean running in Sport mode with manual gear changes (paddle shifting) up to 5th for the first 3,000km, wouldn't it?

Not too sure with the newer Tdi's, but I run in a turbo diesel (manual transmission mind you) by driving normally 80% of the time, 10% of the time with brisk acceleration uphill to 3000 - 3500 RPM to "load" the injectors. 5% of the time would be "lugging" the engine in the max torque band (i.e. highest possible gear going up hill) and the remaining 5% for max engine compression eg coming down a hill in a gear which is suitable to maintain speed without accelerating or decelerating. I only need to do this for the first 1,500km or so, after that she's good.

The 1HD-FTE engine in my fourby has just ticked over 476,400km and is still running as sweet as the day I bought it. Fuel consumption has not deteriorated and has been very steady (fuel records kept from when I picked up the old girl from the dealer with 0.6 km on the clock). Doesn't burn oil at all. Rest of the old girl however is looking a bit battle scarred. LOL.

Having said that, diesels do need to be driven on regular long trips to ensure longevity. They need a good blast every now and then if you're driving predominantly in city traffic. Long distance driving and diesels are made for each other and stop-starting kills diesels faster than toxic curried egg farts in a packed elevator with no ventilation in 35 degree heat.