Lowish Mpg brim to brim tested

[Tomjones1995]

Hello everybody, happy new year! (bit late but there you are)

 

Anyways, I have done a brim to brim test recently to find my true mpg and it was as low as 43. Now I'm aware that's not entirely the end of the world and it is cold winter months but the dash read 49.6mpg over 369 miles.

 

So the question is, can the dash be that far out without it being an 'issue'?And is 43mpg a decent number for a 1.9tdi engine in the winter with mixed driving? What's other people having?

 

Thanks,

Tom

[KenONeill]

On the presumption that this is single carriageway commuting, it's not that different from my Octy (heavier, and different driver). The most reliable figures on the trip computer are "miles since last reset" and "available range".

[Tomjones1995]

11 minutes ago, KenONeill said:

On the presumption that this is single carriageway commuting, it's not that different from my Octy (heavier, and different driver). The most reliable figures on the trip computer are "miles since last reset" and "available range".

Yeah sorry Ken, entirely single carriageway. What do you mean by 'miles since last reset'? Is that the longer trip or the shorter one that resets in two hours or so?

[KenONeill]

1 hour ago, Tomjones1995 said:

What do you mean by 'miles since last reset'? Is that the longer trip or the shorter one that resets in two hours or so?

Don't understand the question.

 

The trip meter resets when you press its reset button, or every 1_000 miles/kilometers, and available range resets when you put fuel in, then counts down to 0.

[Tomjones1995]

1 hour ago, KenONeill said:

Don't understand the question.

 

The trip meter resets when you press its reset button, or every 1_000 miles/kilometers, and available range resets when you put fuel in, then counts down to 0.

Oh right I see. I understood about the available range but my Polo has three trip mileage odometers. One resets after the engine has been switched off for two hours, the other one runs usually until I reset it or it resets itself. I also have a third mileage 'counter' below the main odometer.

 

I reset the second long range trip computer and did the brim to brim test and used an online mpg calculator to calculate the results which came up with 43.6mpg and the dash said 49.6mpg.

 

I'm mainly concerned about the rather large difference in the numbers really. I understand the computers are not entirely accurate but this seems to me a little too innacurate.

Edited 23 January, 2020 by Tomjones1995

[KenONeill]

36 minutes ago, Tomjones1995 said:

the rather large difference in the numbers really

Well, the computer consumption is a guess; I'm not the only person who has set out on a different trip to my usual, and ended it with more available range than I started with!!

[Tomjones1995]

17 minutes ago, KenONeill said:

Well, the computer consumption is a guess; I'm not the only person who has set out on a different trip to my usual, and ended it with more available range than I started with!!

Pretty cr*p guess in my case then. I guess I'll do another test in the summer and see how it fares then.

 

Thanks again,

Tom

[KenONeill]

2 minutes ago, Tomjones1995 said:

Pretty cr*p guess in my case then

Yep. Its only real value is if you notice a sudden change in that value without a change in your use case (including road works as a change in the use case).

[Tomjones1995]

30 minutes ago, KenONeill said:

Yep. Its only real value is if you notice a sudden change in that value without a change in your use case (including road works as a change in the use case).

I see, so it's only use is give you a rough idea of the mpg and to use as a tool for any problems with the car by a sudden drop in the mpg it reads for example?

[VanhireBoys]

I usually get about 720km (450 miles) brim to brim .. I live on country roads - start stop driving in town and a bit of motorway.

 

I know if I get less theres a reason, and a good indicator of trouble should it be a sticking caliper or a siezing gearbox ..!

 

Roughly speaking that works out about 40mpg if you consider that a Fabia vRS has an 11 gallon tank.

 

This of course is a rough guide and hardly laboratory conditions of course ...A lot of uncertainty of measurement, conditions and driving style are a big influence.  I have squeezed 50+ mpg out of her on a long trip during the summer...

[VanhireBoys]

16 minutes ago, VanhireBoys said:

I usually get about 720km (450 miles) brim to brim .. I live on country roads - start stop driving in town and a bit of motorway.

 

I know if I get less theres a reason, and a good indicator of trouble should it be a sticking caliper or a siezing gearbox ..!

 

Roughly speaking that works out about 40mpg if you consider that a Fabia vRS has an 11 gallon tank.

 

This of course is a rough guide and hardly laboratory conditions of course ...A lot of uncertainty of measurement, conditions and driving style are a big influence.  I have squeezed 50+ mpg out of her on a long trip during the summer...

 

 

 So I  cocked that one up .. Its actually a 9 gallon tank not 11 so thats 50mpg .. Back to sleep ...  

[Tomjones1995]

26 minutes ago, VanhireBoys said:

 

 

 So I  cocked that one up .. Its actually a 9 gallon tank not 11 so thats 50mpg .. Back to sleep ...  

I dunno, I thought it was a 9.9 gallon/ 45 litre tank. I think theres alot of different ideas as to how large the capacity is. Some say 45l, some say it's closer to 50l.

I didn't completely empty my tank to get 369 miles. I suspect if I had it would of been more like 410-420 miles. I refilled the tank once I was halfway through the 'redzone' on the fuel gauge

[sepulchrave]

34 minutes ago, VanhireBoys said:

 

 

 So I  cocked that one up .. Its actually a 9 gallon tank not 11 so thats 50mpg .. Back to sleep ...  

 

10 gallon but who's counting.

[sepulchrave]

1 minute ago, Tomjones1995 said:

I dunno, I thought it was a 9.9 gallon/ 45 litre tank. I think theres alot of different ideas as to how large the capacity is. Some say 45l, some say it's closer to 50l.

I didn't completely empty my tank to get 369 miles. I suspect if I had it would of been more like 410-420 miles. I refilled the tank once I was halfway through the 'redzone' on the fuel gauge

 

You are correct, many people can squeeze nearly 50 litres in by filling it right to the cap.

[VanhireBoys]

I think we will settle at 10 then ....!! .. Dont heed me .. Im just in a mode today where stuff here is all going wrong ....!

 

Any future calculations I make on mpg are going to be calculated from the pump and distance reading ....! No guesswork ....!

 

Did you ever regret putting your 10p into a ring ....

[Tomjones1995]

1 hour ago, VanhireBoys said:

I think we will settle at 10 then ....!! .. Dont heed me .. Im just in a mode today where stuff here is all going wrong ....!

 

Any future calculations I make on mpg are going to be calculated from the pump and distance reading ....! No guesswork ....!

 

Did you ever regret putting your 10p into a ring ....

Me? Only hundreds of times haha

[MrPomeroy]

When my fabia Vrs Diesel was running properly I usually got around 400 miles for about 42-45 quid (depends on where I filled up) and that was averaging 70-75 mph on mostly motorway runs.

 

Going from Bristol last September on a sunny day to Northampton I stuck it at 70 max both ways and the trip computer said 71 mpg average, though I am not sure how accurate that really is.

 

As I now own an Audi TT 2.0 petrol that old figure looks bloody lovely to me!

[Tomjones1995]

17 hours ago, MrPomeroy said:

When my fabia Vrs Diesel was running properly I usually got around 400 miles for about 42-45 quid (depends on where I filled up) and that was averaging 70-75 mph on mostly motorway runs.

 

Going from Bristol last September on a sunny day to Northampton I stuck it at 70 max both ways and the trip computer said 71 mpg average, though I am not sure how accurate that really is.

 

As I now own an Audi TT 2.0 petrol that old figure looks bloody lovely to me!

For me, I think it took £52 for the 369 miles I did, but it depends on the fuel prices at the time that you had your fabia in comparison to what they are now. Though I'm sure the difference would be minimal

[sepulchrave]

This thread is FASCINATING, I can't wait for the next thrilling installment!

[Bogwoppit]

I've had two Fabia vRS's.:

On the 07 plate (BLT engine code) the mpg computer was always full of ****, over estimated by the numbers the OP suggested if not more. This was compared to calculating brim to brim method.

My earlier 05 plate Fabia (ASZ engine code) the mpg computer was fairly accurate, always within 1mpg of the calculated numbers.

 

Both cars were standard, but the BLT had the hesitation fix done (EGR metal gasket drilled to approx Ø11mm)

 

So yes the dash can be that far out.

[Tomjones1995]

35 minutes ago, Bogwoppit said:

I've had two Fabia vRS's.:

On the 07 plate (BLT engine code) the mpg computer was always full of ****, over estimated by the numbers the OP suggested if not more. This was compared to calculating brim to brim method.

My earlier 05 plate Fabia (ASZ engine code) the mpg computer was fairly accurate, always within 1mpg of the calculated numbers.

 

Both cars were standard, but the BLT had the hesitation fix done (EGR metal gasket drilled to approx Ø11mm)

 

So yes the dash can be that far out.

Thanks for the info. I'd heard that one of the engine codes had a more reliable mpg trip computer than the other, just thought it was the BLT

 

Good to know that I'm not the only one