Gotta love Tdi economy

[kaanage]

I have a 2009 Caddy TDI manual that has averaged 7.6L/100km over its life

So you don't even average the Urban consumption figure of 7.3l/100km ?

I've got a 09 Caddy Maxi TDI filled with tools and material, carrying ladders and I get on average 660 - 700k a tank without running it into the red. I worked out that it's 7.4 - 8.2L/100km.

I work mainly in Melbourne CBD so most of those km are city. I estimate 60-70% of my driving is city driving in traffic.

This makes more sense - you can't do much about traffic crawls unless you perform manual start/stop

[Transporter]

I am glad you posted that fmflex. I have a 2009 Caddy TDI manual that has averaged 7.6L/100km over its life. The worst I've got is 8.1L/100km in city traffic and only once got below 7 with a 6.6L/100km which was a very gentle country trip in Victoria. Half of my driving is inner city Adelaide, the other half country driving (110km/h SA) and I am rarely carrying a load at all. With the exception of the 6.6 figure (where I was averaging probably around 80-90km/h) I hardly notice any improvement to fuel economy with country driving. Admittedly I don't dawdle and I do overtake (gotta love TDI torque!) but VW's official 'Extra-Urban' figure of 5.3L/100km seems like they are dreaming

Are you driving mostly short trips? Are you using BP Premium? What tyres do you use and what pressure? Also big influence on the fuel economy has the driver, saying that I don't mean that you don't know how to drive to get good fuel economy. Also remember when you have the foot of the accelerator the engine uses 0 fuel, in most conditions.

My bet is that most of your trips are too short.

[epicmac]

I just got 884km @ 5.98l/100km. Not the lowest consumption I've got, but the most out of a tank. I find it difficult to drive for economy, enjoy the torque too much.

Sent from my HTC One X using Tapatalk 2

[Tuning Dynamics]

The caddys need software changes.
The low power-spec caddys can gain 40% (see our dynos) and not lose any economy, so very esy to do economy tuning to gain savings at the pump.

[kaanage]

True - I get better fuel consumption with my Viezu 'Power' remap than I did in stock and Preeny has a powerchip device to richen his fuel delivery.

The great thing with this sort of change is that the low end torque is boosted enough that you can drive the car off idle so you can shift up earlier. If the Caddy isn't hugely loaded, you should be able to shift so that it drops to ~1200rpm in the new gear and still pull cleanly on flattish roads - this does wonders for fuel economy.

see our dynos

Are you guys Viezu resellers? I notice you use their widget for quoting model power increases.

[rearrange]

Are you driving mostly short trips? Are you using BP Premium? What tyres do you use and what pressure? Also big influence on the fuel economy has the driver, saying that I don't mean that you don't know how to drive to get good fuel economy. Also remember when you have the foot of the accelerator the engine uses 0 fuel, in most conditions.

My bet is that most of your trips are too short.

Overall I drive a mixture of trip lengths. I do live/work in central Adelaide so subsequently there are traffic lights and stop/start situations every time I drive. However I prefer to walk than drive if I can so I'm not driving to the end of the street and stopping again. That said I understand my fuel economy is no surprise for my city use, but for the country driving not to be better is weird. I mean I drive with the car in fifth gear (manual trans) with the cruise control set at 115km/h and drive for hours in SA with few moments of slowing down and few hills. Other than driving more slowly I don't see how I could be doing anything differently.

Yes, I do use BP Premium if I can.

I have wondered about my tyres: they are 'Michelin Pilot Sport 225/45R17 91W': Pressure 36PSI. I know they are performance oriented tyres and are arguably overkill for a Caddy unless I was driving it around the Nurburgring (Sabine Schmitz in a diesel Transit anyone??) but could they be responsible for extra fuel usage that works out to be almost 50% more than the official non-urban cycle?

And no, no faults have been found when servicing it.

[rearrange]

So you don't even average the Urban consumption figure of 7.3l/100km ?

Correct

[brad]

How many km have you done?

[gldgti]

Overall I drive a mixture of trip lengths. I do live/work in central Adelaide so subsequently there are traffic lights and stop/start situations every time I drive. However I prefer to walk than drive if I can so I'm not driving to the end of the street and stopping again. That said I understand my fuel economy is no surprise for my city use, but for the country driving not to be better is weird. I mean I drive with the car in fifth gear (manual trans) with the cruise control set at 115km/h and drive for hours in SA with few moments of slowing down and few hills. Other than driving more slowly I don't see how I could be doing anything differently.

Yes, I do use BP Premium if I can.

I have wondered about my tyres: they are 'Michelin Pilot Sport 225/45R17 91W': Pressure 36PSI. I know they are performance oriented tyres and are arguably overkill for a Caddy unless I was driving it around the Nurburgring (Sabine Schmitz in a diesel Transit anyone??) but could they be responsible for extra fuel usage that works out to be almost 50% more than the official non-urban cycle?

And no, no faults have been found when servicing it.

mmm.... the tyres shouldnt cause that much of a problem.... I know skinny tyres are good for fuel economy, but I've always managed ot get excellent fuel economy with all my diesels, even with fat tyres. I have 225/45/17 on my skoda, I used to have 205/45/16 on my mk3 diesel too - I always got low 5's in that.

I do run them pretty high - 40psi usually.

[kaanage]

Managed 14.6l/100km today


while doing 7 laps at Sandown racetrack

[kaanage]

with the cruise control set at 115km/h and drive for hours in SA with few moments of slowing down and few hills. Other than driving more slowly I don't see how I could be doing anything differently.

The speed you are cruising at is probably the big factor - the tall profile of the Caddy adds a lot of extra frontal area over a Polo, Golf or Octavia so the penalty for cruising above 100km/h would be noticably larger.

[rearrange]

How many km have you done?

19,000km

[rearrange]

The speed you are cruising at is probably the big factor - the tall profile of the Caddy adds a lot of extra frontal area over a Polo, Golf or Octavia so the penalty for cruising above 100km/h would be noticably larger.

I have wondered about that. I recall reading somewhere once that the 'extra-urban' official cycles were taken driving at around 90km/h at a constant speed on flat roads with no wind or rain etc. This would probably make the difference. I can't imagine myself ever having the patience to test this theory

[ParaBul]

I have wondered about that. I recall reading somewhere once that the 'extra-urban' official cycles were taken driving at around 90km/h at a constant speed on flat roads with no wind or rain etc. This would probably make the difference. I can't imagine myself ever having the patience to test this theory

AFAIK, the "official" figures are all calculated on a dyno, while they're conducting emissions tests. They record what comes out of the tail-pipe during some specific "drive cycles", and that allows them to calculate how much fuel was burned (as a secondary thing). They do some basic corrections to account for different vehicle sizes / weights, but the vehicles are not actually tested on the road.

I read somewhere that some large Merc turbo V8 with 8 speed auto gets through the emissions test without hitting boost, so it establishes some outstanding fuel economy figures - but real world driving will be a radically different result.

[Sharkie]

Getting 600kms consistently out of a 80l tank. 103tdi with 7spd DSG. BP premium diesel only.

Averaging 12+l/100km where VW states 10.1 ..... Real world driving commuting in the city.

Tdi economy is a farce .... Especially when I'm driving. Same commute in the GTI gets me 9l/100km ....