Optimistic MPG Readings

[camelspyyder]

1. Is there any way to re calibrate the in dash MPG metering?  My 105TSi consistently over-reads by about 6%  showing averages of 49 to 53 over a tankful when the brim to brim sums

come out at 46 to 50.

 

2. How big is the tank in reality? I managed to squeeze 52 litres in on one fill-up.

 

 

[Elegance75]

I know the spaceback is 55 litres!!

[Delberthot]

I'm pretty sure the hatch is 55 litres as well

[harisma23]

1. Is there any way to re calibrate the in dash MPG metering?  My 105TSi consistently over-reads by about 6%  showing averages of 49 to 53 over a tankful when the brim to brim sums

come out at 46 to 50.

You are absolutely right!

As I have written in another post:

 

The consumption figures I got in the 5 refills I did so far (in 3700 Km) are :

1. 5.94 - 5.5 lt/100Km

2. 5.53 - 5.2 lt/100Km

3. 6.08 - 5.7 lt/100Km

4. 6.27 - 5.8 lt/100Km

5. 5.91 - 5.5 lt/100Km (actual consumption - maxi-dot avg consumption).

So by now, it's safe for me to say that the maxi-dot avg consumption is optimistic by approximately  0.4 lt/100Km or 7% (to be accurate I don't know which of the two applies).

 

I don't know however if we can recalibrate the MPG metering. I know that in some cars (e.g. BMW) it is posible but I doubt that we can do it officially (that is in the dealerships). I think our only hope is through VCDS.

[camelspyyder]

Well, I'm assuming the fuel burn is measured accurately, so is the odometer and speedometer reading incorrectly?  I will take my gps in the car and check speedo / odo accuracy this weekend if I can.

[harisma23]

Well, I'm assuming the fuel burn is measured accurately, so is the odometer and speedometer reading incorrectly?  I will take my gps in the car and check speedo / odo accuracy this weekend if I can.

The odometer is definitely reading correctly. I am convinced that it is a deliberate trick of the manufacturer (I had the same problem with my previous car, a Peugeot 308) to "flatter" the fuel consumption for marketing reasons.

[camelspyyder]

My other car under-reads by 16% because it is wrongly calibrated for US gallons not imperial gallons i.e. it displays 35 mpg when you are really getting 42 mpg 

 

And it been in production from 1998 to 2010 without the manufacturer releasing a software fix for this issue!!

[bluecar1]

my greenline onboard computer is only out by 0.7% over 30,000 miles

 

swmbo's citgo is 7% optimistic over 10,000 miles

 

somewhere on here I seem to remember there is a constant that can be adjusted with VCDS to improve the accuracy of the trip computer

[The Plumber]

Pretty happy with the Spaceback's computer readouts, which currently average between 48 and 52 on the commute to work, against fuelly fill to fill results of 47 to 49.3.

 

From new fuel consumption had been steadily improving since collecting the car at the end of July, then it took a noticeable dip on one tank full in mid September and since then has been back up then down again. Not sure as to why the dip or following fluctuations, could be the onset of more autumnal weather :wonder:

 

 

TP

[camelspyyder]

Pretty happy with the Spaceback's computer readouts, which currently average between 48 and 52 on the commute to work, against fuelly fill to fill results of 47 to 49.5.

 

From new fuel consumption had been steadily improving since collecting the car at the end of July, then it took a noticeable dip on one tank full in mid September and since then has been a bit up and down. Not sure as to why the dip or following fluctuations, could be the onset of more autumnal weather :wonder:

 

 

TP

 

 

 

My 105 did about 40 mpg on the first tank but loosened up really quickly.  Now gives very similar figures to yours on a 25 mile A/B road commute.  Heavy use of AC drops it down, and both my previous cars on this commute lost about 5 mpg in the winter - what with cold starts etc.

Edited 10 October, 2014 by camelspyyder

[Thecko]

I've found I mostly lose economy because I seem to always end up working right near a big shopping centre/district which causes ridiculous traffic jams heading towards christmas. The new job this year is probably going to be no exception as I'm working right near John Lewis in Cheadle 

[camelspyyder]

I've found I mostly lose economy because I seem to always end up working right near a big shopping centre/district which causes ridiculous traffic jams heading towards christmas. The new job this year is probably going to be no exception as I'm working right near John Lewis in Cheadle 

 

You think you're losing economy?  I don't think anyone else is getting 55mpg from a 1.2 rapid on here.  Are you sure you're not driving a TDi

 

I get 49/50 max pussy-footing it, and mid 40's on motorway.

 

 

Ok forget what I said, I clicked your ECO-link and saw that you get the same MPG as the last 2 posters here (45-49)

 

 

 

Your FUELLY Graphic is hoop.  I bet I'm not the only TSi driver who has seen that regularly and thought WTF???

Edited 10 October, 2014 by camelspyyder

[majorminor]

My understanding is that pretty much all vehicles slightly overstate the speed reading up to the maximum speed limit.

 

This is to avoid any chance of them UNDERreading - which could lead to court action in the event of accidents.

 

We live in litigious times - the manufacturers simply cover themselves.

 

If you have Sat-Nav, you can always see your true speed on there :sun:

[Thecko]

You think you're losing economy?  I don't think anyone else is getting 55mpg from a 1.2 rapid on here.  Are you sure you're not driving a TDi

 

I get 49/50 max pussy-footing it, and mid 40's on motorway.

 

 

Ok forget what I said, I clicked your ECO-link and saw that you get the same MPG as the last 2 posters here (45-49)

 

 

 

Your FUELLY Graphic is hoop.  I bet I'm not the only TSi driver who has seen that regularly and thought WTF???

 

On fuelly make sure you click on the UK units near the fuelly logo on the top left, otherwise you'll be seeing miles per US gallon, which is smaller than a UK gallon.

 

I definitely do lose economy in November/December And probably will once I fill up next as well, traffic jams going to and from work every day so far on this tank :(

[camelspyyder]

Thecko, your signature on here shows 55mpg UK.  If you are actually getting that from a 1.2TSi please share how it's done - whether its driving technique, an eco-re-map, I really want to know  

 

 

59.7 from a tankful!!  :clap: did you drive off a cliff?

Edited 10 October, 2014 by camelspyyder

[camelspyyder]

My understanding is that pretty much all vehicles slightly overstate the speed reading up to the maximum speed limit.

 

This is to avoid any chance of them UNDERreading - which could lead to court action in the event of accidents.

 

We live in litigious times - the manufacturers simply cover themselves.

 

If you have Sat-Nav, you can always see your true speed on there :sun:

 

Yeah, I've always used bolt on satnav to get a true GPS speed readout, but there doesn't seem to be one on SEAT NAV 2.2 (Amundsen).  I'm planning on robbing SWMBO's Satnav this weekend for a speedo check.

[Thecko]

Very few 'short journeys' (most of my drives are at least 20 miles long whether it's to work, or a trip to visit family, etc), and the patience to just do 60 on the motorway when you're driving to work. That's it.

 

I suppose it also helps that I'm in the North West which is actually very flat compared to other parts of the country so my engine will be working less hard to make it's way up hills all the time.

 

And yes, I have the 1.2 105PS TSI, not the TDI

[camelspyyder]

Very few 'short journeys' (most of my drives are at least 20 miles long whether it's to work, or a trip to visit family, etc), and the patience to just do 60 on the motorway when you're driving to work. That's it.

 

I suppose it also helps that I'm in the North West which is actually very flat compared to other parts of the country so my engine will be working less hard to make it's way up hills all the time.

 

And yes, I have the 1.2 105PS TSI, not the TDI

 

Sorry for doubting your 55 average.  I think I could get closer to it if the last 6 miles of my commute didn't involve so many junctions and trips through the gears.  Oh, and I have the 215x17 inch tyres which I havent factored in.

[Thecko]

Ah, yeah, I'm on the standard size tyres with mine, also I rarely need to take passengers on shorter journeys and at least once every 2 months I seem to end up doing a return trip or two to my sister's in south wales which I get epic economy on.

 

There are absolutely loads of factors to take in to account when trying to explain economy and to decide whether it's good or bad. I don't know what it is, but a combination of geography, my driving style and who knows what else has meant that all three of my cars (Mk4 Fiesta, Mk1 Fabia 1.4  mpi and now the Rapid) so far have seen me getting pretty much bang on what the govt mpg figures are for the car.

 

Personally I'd say if you're within 10-15% of the official figures then that's good after taking traffic, terrain and load in to account.

[camelspyyder]

My last 2 cars doing the same commute both beat the government overall figures.  I think this little turbo, in a relatively big car, is less easy to squeeze the mileage out of on single carriageway A & B roads.

[harisma23]

There are absolutely loads of factors to take in to account when trying to explain economy and to decide whether it's good or bad. I don't know what it is, but a combination of geography, my driving style and who knows what else has meant that all three of my cars (Mk4 Fiesta, Mk1 Fabia 1.4  mpi and now the Rapid) so far have seen me getting pretty much bang on what the govt mpg figures are for the car.

 

Personally I'd say if you're within 10-15% of the official figures then that's good after taking traffic, terrain and load in to account.

 

 

You are absolutely right!

While my average consumption (verified - measured after several refills) is 5.97 lt/100Km (47.3 mpg) , I did manage on a short trip of 20 Km (12 miles) in an absolutely flat and almost deserted B-road, with an average speed of 65 Km/h (40 mph) , to get a reading from the trip computer of 2.9 lt/100Km (97.4 mpg) .

Even if we factor in the optimism of the trip computer of about 7%, this should result in an actual average fuel consumption of 3.1 lt/100Km (91.1 mpg) and IMHO this must be the absolute minimum achievable consumption in real world (and of course not on a descent) for a Rapid TDi !

Edited 10 October, 2014 by harisma23

[The Plumber]

Pleased with the high 40's myself, considering the wide 17" tyres and extra weight of the glass roof plus extended tail gate glass (and a spare). It also betters a previous Yeti TDI 110 4x4 and is only 2 or 3 mpg short of the Octy III TDI 150 4x4.

 

 

TP

[camelspyyder]

I'm not saying the MPG is poor.  I just want to correct the dashboard readout that lies about it.

[RapidTrev]

Over three months I've found the Maxidot very accurate (within .5 mpg on each tank), so much so, that I'm now trusting it sufficiently to stop manually calculating my mpg's every time I fill up. 

[WillJohnson]

Yeh its not too bad. TBH my 86bhp 1.2 tsi does soooo amazingly i dont look at the figures at all anymore. I just know if I put £60 of supermarket unleaded in it will do 620 miles before I have to fill up again :-). That is what i call economical (That's me driving 50 miles a day doing 58mph on the M6).