4.2 litres per 100km (67 mpg)

[Blue103TDIDSG]

Had to pick the wife up at Gold Coast Airport (Coolangatta) last night at 8.30pm
From Beenleigh it is about 70kms and I had an hour and a half to get there straight down the M1
Almost no traffic on the motorway so I set cruise control at 85kph and just sat there steering
The 80kph wasn't a problem as I went through 4 lots of roadworks - didn't have to adjust cruise control
Watched the litres per 100 slowly drop and stabilse at 4.2 litres per 100
That's 67 mpg took photo with phone in the dark (when I got there)



On the trip home sat on 100kph, again on cruise control and it returned 4.7 liter per 100km - only 60 mpg
would expect to use more fuel as we were heading north which is "uphill"



Not bad for German engineering - even if it needs Test Defeating Software to do it...........LOL

By way of comparison, did the same trip, well almost - went just past the Airport with the caravan hooked up
at 100kph it used 10.5 litres per 100km

Got a problem with the Avatar as I have a new toy

[Hillbilly]

Have found what the MFD shows and whats real is often quite different

[Blue103TDIDSG]

Have found what the MFD shows and whats real is often quite different

Any idea by what amount ??
Although thinking about it, one reason could be this
When I picked up the Scirocco (avatar) in January this year the sales manager told me that it had just been "recalled"
Even before I took delivery. It has the little sticker on the boot floor with the recall details on it
Apparently the speedo was reading true and the ADRs require that the speedo MUST over-read by between 4 and 14kph
He told that I can sit 5kph over the limit and I will quite safe
Big brother's way of slowing the population down
So I guess to answer my own question is that it (the Scirocco) will be 5% high
The Yeti reads about the same - checked with GPS and it over reads by 5kph
So the above 4.2 and 4.7 are probably 5% high
Still pretty good though

[Hillbilly]

A speedo CAN read true and up but not under .My Cruiser was bang on at 100kph. The rule says it MAy read up to 10%+-4 fast but not slower than actual speed
The consumption and the speedo are probably not connected. Others have said that the MFD readout is often more optimistic than actual measured consumption.

The only true way I know is to fill it at the same pump to the same level several times and work out against K's covered. Different pumps can cut off at different levels as well

[Blue103TDIDSG]

A speedo CAN read true and up but not under .My Cruiser was bang on at 100kph. The rule says it MAy read up to 10%+-4 fast but not slower than actual speed
T

I had a Turbo Diesel Landcruiser for 20 years and it was bang on pretty well from 60 to 100kph - the beauty of the electronic pulse speedos which were new when I got the car.
I questioned him on this and he said that the interpretation is that it is to be a minimum of 4kph OVER read (the +4) then another "optional" 10% on top of that giving upto 14% over-read - I accept what he said because he had no reason to lie
VW wouldn't put out a recall to adjust speedos if it wasn't required and there is the sticker in the boot as "proof"

Fact is the service I got from Cricks at Springwood (Qld) was absolutely fabulous
Car was stored for couple of months in their storage area and they put a car cover on it.
I asked them if I could put my blankets underneath the car cover to stop scratching and it was OK
That's why he told me about the recall because they had to remove the blankets and car cover to do it and I had asked that the car not to be used for test drives, so he was just letting me know in case I noticed that they had been moved.
Fact is he said that my bum was the only one that would sit in the driver's seat - no customers would go near it
Full story here page 42, post #412 if you're interested
The official I have ordered/received my new Scirocco thread

The consumption and the speedo are probably not connected.

Think you will find that the trip computer will get its info from the speedo sender, which is basically just a pulse generator
that gives a known number of pulses per revolution of the gearbox output shaft. This is then converted into kph on the speedo and kms travelled in the trip computer. So depending where this "inaccuracy" is it will affect everything that uses it.
Have read on the Golf forum that you can adjust the speedo reading via the CanBus and VCDS.

Others have said that the MFD readout is often more optimistic than actual measured consumption.

Curious to know if it is the same as the speedo error

The only true way I know is to fill it at the same pump to the same level several times and work out against K's covered. Different pumps can cut off at different levels as well

Not practical for me as I don't do enough kms so would take too long - 23K in 3 years
and I usually only fill tank to a bit over 1/2 unless we're going on a long run but having said that we are 20kms away from "civilisation" so don't do short runs either

[The_Hawk]

HillBilly is right, the speedo and what the computer knows are two different numbers.

In the goold old days you'd be right (Blue103TDIDSG), the pulse would run the odometer and the speedo so it was all connected which is why those "speed check" signs where you measure off 5km would actually work.

These days in fancy computer driven cars it's possible to use different numbers for different reasons (which is a little annoying).

So in VW (and Audi/Sokda/Seat) the computer knows how fast you are really going but displays a higher speed on the speedo, you can test this by setting your cruise control to 100km/h on some nice level ground then reset the trip computer and watch the average speed... it will be 95 or there abouts.

So the odometer is correct, average speed is correct and everything else should be too... just the displayed speed it out. As has been said, to meet ADR you can read *over* the correct speed by xx% but never under.

What frustrates me (and many other people) is that they know the correct speed but refuse to display it (I don't know if this is to allow people to creep over and not actually speed or what??)

In any case I've looked into this far far too much

But here are some interesting facts for you.

Yes your speedo (and odometer) accuracy will change as your tyres wear because they whole system is based on revolutions of some part which eventually turns the wheels xx times per km, a calculation then returns current speed. When the tyre is brand new it has a larger circumference as it wears it gets smaller which means it covers less distance per rotation which in turn mean the car thinks it's going faster than it really is...

Bottom line, if your speedo was 100% spot on accurate with a new tyre it would never read over so anyone saying tyre wear is a reason for speedo's to be less accurate are flat out wrong.

Next, wheel and tyre choice. Yes different wheel and tyre combos will change the circumference. I don't have the calculations in front of me right now, but from memory the difference was only something like 2% across the whole range. So if the computer was set with that in mind the most innaccurate reading would be much closer than it currently is.

When in add in tyre wear AND different wheels I did some calculations a while back and it was something like 7-8% worst case. (which is just worse now)

If VW were to calculate the possible wheel/tyre combinations and the possible speedo error that they would

[Hillbilly]

I had a Turbo Diesel Landcruiser for 20 years and it was bang on pretty well from 60 to 100kph - the beauty of the electronic pulse speedos which were new when I got the car.
I questioned him on this and he said that the interpretation is that it is to be a minimum of 4kph OVER read (the +4) then another "optional" 10% on top of that giving upto 14% over-read - I accept what he said because he had no reason to lie

Im sorry but he is giving you HIS interpretation of the rule The correct one is what I said It can read dead on as mine did and still be legal.

He is just covering his arse in case you put bigger wheels on it

Here is how they have to be tested and If you can do the sums you're better than me.
https://www.legislation.gov.au/Details/F2006L01392

A simpler explanation is here in the second paragraph Speedometer Accuracy - Speedo Regulations | RACQ Perhaps next time you see the man you could show him what is correct. The only bit he got right is that they can be a max of 14 k fast.

Basically they calibrate the speedo to be within tolerances with every legal size of wheels and tyres for the model. ( look on the tyre placard)

Yours would be the only VW speedo that seems to be accurate as both of mine are at least 6 k over and if you read this thread so is everyone elses

Ridiculous Speedometer Error and On Purpose !!!


As far as where the speedo drives from AFAIK it is from one of the rear ABS sensors which measures the speed of rotation of the wheel. As said in the old days they were cable driven off the rear of the gearbox shaft. Bet you cant find a cable there today.

They are electronic and in some models can be adjusted with VCDS ( not in mine) You alter the number of pulses in one of the bytes in a certain module.

If you have a RNS510 and modified firmware you can access a menu which will show you true speed from the cars ECU.

[Blue103TDIDSG]

Thanks for your replies
OK...technology moves on
Can see where VW are coming from - good 'ole PC once again
Just covering their bum to not read over with the largest wheel tyre combination for the car - and suffer the over-read with smaller ones
and probably a just in case bugger factor added in as well

My Scirocco is an MY16 with serial number just over 1800, so relatively early production of the new model
guess there must have been a stuff up in the software as the wheels and tyres didn't change from the MY15

Can't change the tyre wear factor - always been there
Nice to know that the odometer is relatively correct

In passing, my Yeti has a Zenec GPS and it shows the speed - always 5kph lower than speedo

OK then, back to Hillbilly's comment about MFD being optimistic.....Why is this so

[Hillbilly]

Because it supposedly reads consumption in real time and when you are going down hill it reads it as zero kpl because you have your foot right off it.

Apparently from what others say on here, in all sorts of models it reads under true consumption. Im not so fussy, tank empty, fill it pay the man and away we go. More to worry about than that.

I seriously doubt any VW except perhaps the UP will get under 5 L per 100km. My Polo gets 5.1 on a long trip at speed limit if Im careful and its a 1.2T

Your pics show you are on readout 2. What does readout 1 say

[Blue103TDIDSG]

Your pics show you are on readout 2. What does readout 1 say

Only have 2 readouts
Readout #1 is reading zero because it is the current usage and engine is off, and as you say downhill reads zero
Reading #2 is the average from last reset
On the above trip I reset as I left so the 4.2 was average for trip down and 4.7 was for there and back albeit they are probably low
fact is the trip back actually used 5.2 if my maths are correct since it was averaged over the entire trip
Should have reset as we left to come back

Is there another reading apart from these 2 ??

I seriously doubt any VW except perhaps the UP will get under 5 L per 100km. My Polo gets 5.1 on a long trip at speed limit if Im careful and its a 1.2T

We also have a Fiat 500 Twin Air that has 2 cylinder 875cc engine - turbo of course with sophisticated variable valve timing system. Goes very well but driven carefully and on a long trip it will get under the 5 litres and that is by filling and doing the maths as you do.
But it is usually more fun to drive it hard and with the paddle shifts is a lot of fun the result being that the trip computer usually sits around the 6 liters per 100 mark. I guess it probably read optimistic as well ??