Fuel consumption/DPF issues 1.6 TDI "Blue motion technology"

[dcdick]

Anybody interested in comparing consumption figures with my Golf ?
Anybody any opinions of the fuel economy issues ?

To start things off.............

Speedo 630 miles.................................. Current consumption (mpg) 48 overall & 47.2 indicated since last fuel added. By calculation against fuel filled (assuming odometer is correct) is that car readout is 2% optimistic, for me this is close enough for comparisons.

Initially consumption had climbed to 54 mpg until regen started happening at switch off after "short" journeys.

It appears that the filter was "clean" until approx 280 miles then regen started with a resultant increase in consumption.

VW say that the minimum journey in my car should be 15 miles or be prepared & accept that the PDF will run purge cycles & could run for up to 30 mins after end of journey.

This car was bought purely on the basis of economy over the petrol (1.4) alternative & the lease cost was the same so on my estimated mileage of 10/11,000 I should be in the most cost effective motor. The DPF issue was discussed at the time of choosing the car & I was told that it should not be a problem.

Average journeys ? mileage wise, 15-20 ranging from 3-4 up to 50-60 miles with occasional runs of 100+ miles.

I have raised this issue with VW & await there response with some interest.

D

[pango1in]

I'd add a couple of questions to the list:

1. Would using premium fuels help? Bp Ultimate or VPower are supposedly cleaner than supermarket fuel and don't clog up DPFs as much (along with keeping your engine clean).
2. Does the ECU adapt over time to your driving style? I.e. adapt the air/fuel mix depending on whether you are a boy racer or a more cautious driver (I noticed this a lot when I had my 120d - though it took about 1/2 a tank to take effect). This can increase your MPG significantly.

[dcdick]

I'd add a couple of questions to the list:

1. Would using premium fuels help? Bp Ultimate or VPower are supposedly cleaner than supermarket fuel and don't clog up DPFs as much (along with keeping your engine clean).
2. Does the ECU adapt over time to your driving style? I.e. adapt the air/fuel mix depending on whether you are a boy racer or a more cautious driver (I noticed this a lot when I had my 120d - though it took about 1/2 a tank to take effect). This can increase your MPG significantly.

Interesting thoughts................running on Shell "standard" at the moment as they are 2 garages I normally use for fuel. Easy way to find out is to run the fuel down & put £40 worth of "super" in & see what happens then do the sums.
ECU adapting to driving style............ now there is a thought................ no signs of that happening as my driving "style" is reasonably constant (certainly not "boy racer")

This begs the question as to what effect the 4 choices on the DSG box give you...........currently running "eco" with the odd short period of "sport" when I need a bit of "urge" .

D

[Guest 2]

I you want to log your mpg accurately brim to brim then set up a Fuelly account - A3 (Audi A3) | Fuelly

[pango1in]

Interesting thoughts................running on Shell "standard" at the moment as they are 2 garages I normally use for fuel. Easy way to find out is to run the fuel down & put £40 worth of "super" in & see what happens then do the sums.
ECU adapting to driving style............ now there is a thought................ no signs of that happening as my driving "style" is reasonably constant (certainly not "boy racer")

This begs the question as to what effect the 4 choices on the DSG box give you...........currently running "eco" with the odd short period of "sport" when I need a bit of "urge" .

D

Shell standard is better than supermarket fuel (apparently...), but not as good as Ultimate of VPower. I've also heard that some two stroke oil in a tank of diesel can work wonders too (about 200:1 ratio). I've noticed our car get quieter on a few tanks of Ultimate, and get better on startups - less clatter, less black smoke. If we had a DPF, presumably it would be cleaner???

According to BP, Millers etc. doesn't work very well, as not integrated into the fuel at refinery stage, as it Ultimate. Could just be marketing though...

I guess if you drive conservatively, you should already be doing the maximum MPG your ECU will allow..........

[mcmaddy]

You won't see any difference using normal shell fuel to shell vpower or bp ultimate other than your wallet. normal shell will do just fine but avoid Morrison's fuel at all costs due to the high bio crap they use. sainsburys has been ok on mine if not slightly clattery on start up. switched to normal shell and less nose but no considerable increase in mpg.

[dcdick]

I you want to log your mpg accurately brim to brim then set up a Fuelly account - A3 (Audi A3) | Fuelly

I don't believe in filling to the brim on every fuel up, normally just stick in £40 when the fuel gauge gets near the red markings. I did some calculations when I first got the car & the display readings were within 2% of my worked out consumption & close enough for me.
If I read your log correctly your mpg is low as well ? (or is that down to your driving "style" ?)

D

[pango1in]

You won't see any difference using normal shell fuel to shell vpower or bp ultimate other than your wallet. normal shell will do just fine but avoid Morrison's fuel at all costs due to the high bio crap they use. sainsburys has been ok on mine if not slightly clattery on start up. switched to normal shell and less nose but no considerable increase in mpg.

I would disagree with that assessment, apart from supermarket fuel producing more clatter (a sign of inefficient combustion).

Shell fuels only advertise cleaning products in their fuels, which will help keep deposits off of your engine (valves and injectors), thus keeping it running as well as possible. Shell also claims to have synthetic diesel in their fuel, which should burn cleaner meaning less smoke.

BP Ultimate claims to have cleaning additives too, which will clean a dirty engine and protect it from rust too. BP also claims its Ultimate fuel has a higher cetane value than normal fuel (which shell’s doesn’t claim – although some tests show both have a higher cetane value – so not sure what to believe about Shell’s here). Higher Cetane will make the mixture burn more efficiently and at the right time in the compression cycle, meaning less clatter, less smoke and better performance/mpg.

BP ran a test (somewhere on youtube) where an audi had half its engine run on normal and half on Ultimate. After 5000 miles the half on Ultimate was still very clean, the other half was pretty mucky.

Of course you could use Millers as your own additive, but I have seen BP claim that those additives will never work as well, as they weren’t added during the fuel’s refining process. A fifth gear test (or something like it on youtube) confirmed this.

The important point seems to be this: If your engine is caked in grime, then both fuels will help clean your engine and increase your MPG, compared to normal or supermarket fuels. If your car is already clean (e.g. new), then you should notice very little difference. However, you should possibly see more difference with BP Ultimate, as the higher Cetane should give you some additional performance boost (although would you really notice it in real life with a clean engine???).

I have been using BP Ultimate for the last 4 tanks in my car at present. It doesn’t have a dpf. I have noticed that the car is quieter, has literally no black smoke or smell on startup and the engine revs more freely without labouring. Previously, I had been using supermarket fuels. I haven’t noticed any MPG increase, but my driving isn’t consistent enough to run anywhere near a scientific test (presumably this should be done over at least 5000 miles to iron out the kinks).

One test I found on google showed that Ultimate gave a small increase in acceleration (about 0.2 secs to 60) in petrol cars over normal fuel. It also found that a diesel car went from 13.6 to 13.1 to 100 by using Ultimate, rather than normal fuels as it had been used previously.

http://www.caranddriving.com/feature...20ultimate.pdf

It’s not entirely scientific, but better than untested individual experience/preference (like me).

So, my question is this: I wonder if using these fuels will also slow the build-up of soot in the dpf as well, due to the better combustion process, less smoke generally and cleaner engine?

Perhaps those experiencing dpf problems could try it and let us know whether they experience less dpf regens? If it raises the mpg from 48 to, say, 55, then the additional cost is more than outweighed by the mpg increase over constant regens.

My preference would be Ultimate, as BP claims that it does more that Shell’s, but up to you.

[dcdick]

So, my question is this: I wonder if using these fuels will also slow the build-up of soot in the dpf as well, due to the better combustion process, less smoke generally and cleaner engine?

Perhaps those experiencing dpf problems could try it and let us know whether they experience less dpf regens? If it raises the mpg from 48 to, say, 55, then the additional cost is more than outweighed by the mpg increase over constant regens.

My preference would be Ultimate, as BP claims that it does more that Shell’s, but up to you.

OK looks I'm the first "tester" on this ................I'll be re-fuelling in a few days & I'll go with the "super" version of diesel & will see how it goes over 3 lots of this (approx 20 gallons of fuel) which should be enough to show any improvement.

At the moment it looks as though this "regen" cycling is costing me around 5-6 mpg in extra fuel used.
If by being cleaner/better fuel it can even half the fuel wasted by active regeneration that would be around 7p per liter which would cover the extra cost of ultimate/premium itself & if as a consequence the car gets another 4-5 mpg/better performance I'm in profit

Time will tell of course....................interesting to see how this pans out

D

[Guest 2]

I don't believe in filling to the brim on every fuel up, normally just stick in £40 when the fuel gauge gets near the red markings. I did some calculations when I first got the car & the display readings were within 2% of my worked out consumption & close enough for me.
If I read your log correctly your mpg is low as well ? (or is that down to your driving "style" ?)

D

I lost track and stopped logging the fillups and not doing brim to brim hurts the figures too.

I do 600 miles per week, all motorway and very little town driving so the car is being used to its potential fuel economy wise.