Fuel reserve

[D402]

Had to make an unplanned journey yesterday starting with a nearly empty tank. Result was driving about 6 miles with zero range and a 66.5 litre fill up. What's the furthest anyone's driven once the predicted range has dropped to zero?

[Dieselgate]

Probably similar for me although I don't think I have ever got more than 65 litres in. On a previous car I had (Volvo S60) I got more than the quoted fuel tank capacity in at least a couple of times and on my wifes Polo GTI I have done the same.

[Ootohere]

A quoted tank of 45 litres is a 45 litre tank.  You might well get 7 more litres up the pipe so brimmed if you brim.   Same with any tank.   Many do not want to brim, or on cars with tanks that can vent, actually vent before a trip. 

[MartiniB]

@D402

have you met this thread?

in to declared 66l can be filled 70l

-> https://www.briskoda.net/forums/topic/408362-fuel-tank-capacity/

 

 

[J.R.]

The vehicle has a "virtual" reserve capacity of 5-7 litres which is created by the fuel guage and distance remaining readouts being fiddled in the last 1/4 of a tank.

 

The stated capacity is the stated capacity and whilst you might possibly be able to add another litre by overfilling the filler neck no way is that volume 5 or 7 litres, imagine 7 litre bottles of water laying down line astern and compare that to the length and very small diameter of the filler neck. People think they are squeezing in another 5-7 litres because the pump nozzle has stopped delivering due to the back pressure of overfast filling, I always slow down the flow on the last 10 litres, its faster overall if you want to fully fill the tank.

 

To answer the OP's question

2 hours ago, D402 said:

What's the furthest anyone's driven once the predicted range has dropped to zero?

 

A minimum of 100kms/60 miles on each and every tank of fuel for the last 20 years and have never run out aside from when the tank sender was faulty and never filled the tanks to their full capacity although I did get 59.8 litres in recently which was pushing it too far trying to get to the next autoroute exit rather than pay the 20% at the services, I think I had gone 80 miles or more but had stopped looking, I had misjudged the distances and knew it was really touch and go.

 

Filling up when the fuel light comes on gives peace of mind but you refill 5 times when it could have been 4, maybe even 4 times when it could have been 3, thats a lot of time over 20 years!

 

If you look at the range showing when you fill the tank that is precisely the range you will get if you disregard the untruths of the zero miles remaining, I fill up after 600 miles, it would be 520-550 if I believed what the fuel guage and distance remaining displays were telling me.

Edited 1 March by J.R.

[Ootohere]

@J.R.  yes yah. Not no nae never.  With a Fabia MK2 vRS with a 45 litre tank and down to maybe 40 mile range and still able to get 52 litre in.   Actual is better than theory and there will be those on this forum that have done exactly this. 

[J.R.]

Are you saying that I have not actually done what I say for every fill up over the last 20 years but am just theorising?

 

Some of the quoted tank volumes do not correspond to all the models, mine showed 55 litres but it is 60 litres.

 

Maybe I misunderstood, it is not a theory that the fuel filler volume cannot be 5-7 litres, it was observation and mathematics.

 

In 2016 your claim of 5 litres expansion volume was at odds with those who had measured it:

 

 

Whatever those like you or I will run the vehicle as far as we dare and squeeze in as much as we can, brimming is no risk with a diesel but can screw the evaporative cartridge emissions system on a petrol.

 

OTOH running out of fuel on a CR Tdi is major league risky.

[Ootohere]

@J.R.  the person with the post about the BP top up was doing it in a MK3 Fabia.  My experience was never with MK3,s. It was 70,000 miles or so of MK2 Fabia vRS and brimming and venting those to get as much super unleaded in before trips into regions north of Inverness where getting 99 Ron was and is not always readily available.  So I might well be comparing apples and pears.  But then I have run plenty other VW group vehicles and brim them and like to see how much fuel I can get in and range I have and hyperming

or comparing using Coasting mode or other uses.  Always DSG s .

[Bap33]

12 hours ago, D402 said:

Had to make an unplanned journey yesterday starting with a nearly empty tank. Result was driving about 6 miles with zero range and a 66.5 litre fill up. What's the furthest anyone's driven once the predicted range has dropped to zero?

The max I've driven with 0km autonomy remaining was something like 20 km.

I didn't try more. 'Diesel roulette' may be risky for your engine and for yourself (depending on what kind of SWMBO model, you have... 🤭)

 

Joking aside, since autonomy is an assessment based on the way you've driven on the latest miles, the real remaining autonomy once dashboard displays 0, can vary significantly.

 

Regarding fuel tank capacity, the maximum volume I've topped up is around 68.5 l

 

[J.R.]

9 minutes ago, Bap33 said:

'Diesel roulette' may be risky for your engine and for yourself (depending on what kind of SWMBO model, you have... 🤭)

 

That made me laugh! I genuinely had not considered that very important consideration, little wonder so few other people do as I do.

 

And yet they are always the ones to either run out or leave the vehicle running on fumes!

[xman]

Never driven to Zero miles, I try to avoid unnecessary stress. I've seen 76 litres to 1st click with 70 miles remaining so thinking mine has a 80 litre tank.

 

Oversize tanks are optional on some Audis

 

https://www.chroniclelive.co.uk/news/motoring/motoring-news/highway-code-changes-coming-force-26889345

 

https://www.motoringresearch.com/advice/illegal-run-out-fuel-motorway/

 

 

 

Edited 2 March by xman

[JR RS]

I've driven 30km when the Range was showing zero.

I drove a total of 981 km on that single tank!!!

I've got a 220 (162TSi).

 

The Superb comes with 2 different tank sizes - standard 66L size and a larger 75-78L size.

PR codes:-

- 0M4 = standard fuel tank

- 1Z2 = Increase in initial standard fuel filling

 

Hence if u have both PR codes, u have the larger tank.

The larger tank is only available in certain markets.

 

I regularly fill up 66 to 71L each time.

Most I've put in is 74.8L.

[Sheriff]

You lot are a lot braver than me!! I think I'm pushing my luck if I get down to a range of 25 or 30 miles 🤣

[J.R.]

I did a 500 mile motorway journey a week ago so got less economy than I usually do, hardly used the car this week, odometer shows 525 miles and 10 miles remaining range, this time I wont be using that and an additional 50+ miles because I will fill up tomorrow so as to have no fuel stops on the return journey on Monday.

 

It will be interesting to see how many fewer litres I get in than normal, I am betting on 53 or 54 litres.

 

Many fewer is probably very bad English.

[naster]

On 01/03/2024 at 12:23, D402 said:

with a nearly empty tank

As pointed out, that could be a costly trial for a diesel engine. Not only running out and priming trouble, risk of air bubble damage. Also, low fuel level, despite presence of a return fuel cooler matrix, can cause condensation of water vapour from cold air in a nearly empty tank, or, reduce fuel viscosity and lead to incorrect combustion. The minimum quantity acts as a cooling buffer too. Yes, there can be one-offs but I would rarely let remaining range drop below 100km. I can plan a 1300km drive with a single top-up without getting down to the red line.

[numskull]

On 01/03/2024 at 23:32, J.R. said:

 

That made me laugh! I genuinely had not considered that very important consideration, little wonder so few other people do as I do.

 

And yet they are always the ones to either run out or leave the vehicle running on fumes!

 

According to a friend who’s an RAC Tech, in their experience, the vast majority of those idiot drivers who run out of fuel, are men. 

[J.R.]

Why do you deem someone who runs out of fuel an idiot?

[Ootohere]

Unfortunates maybe.   I would like to hear the reasons some give.  Faulty fuel gauge and not familiar with the vehicles sounds OK.

 

Idiot might be a bit strong as could be muppets. 

Just a Silly Billy, 'not the full shilling' , 'a sandwich short of a picnic,'    Risking it for a biscuit or to save a few pence a litre to get to a cheaper place might be common. 

 

PS.

I was driving a mate and towing a trailer to go collect a car.

Meant to stop in Aberdeen to fill up with him paying, forgot as catching up on news. 30 miles north having passed a filling station by 1 mile the car spluttered and i was out of petrol.

Dangerous bit of road uphill and he went with the empty can from the boot to a couple of houses, one with a gyro copter and beach buggy outside but no luck.

So thumb out and he went and got a gallon and got a lift back to me. 

That was about 4 years ago, the time before that i just got to the pumps & that was 35 years ago taking a friend and horsebox trailer to get a horse and once the horse was loaded and heading south on the A9 i was getting half the MPG and Blair Atholl filling station was closed and it turned out she had no money with her and in Pitlochry they took my Family Allowance book as security and let me fill the tank.

 

EDIT.

Edited 7 March by Rooted

[numskull]

21 hours ago, J.R. said:

Why do you deem someone who runs out of fuel an idiot?

Hmmmm… a lack of refuelling may’ve been an excuse in the early 20th century, before the introduction of the fuel gauge and before ‘000’s of petrol stations were available, but not in the 21st century. 

[xman]

If I ran out of fuel, I would probably think "What an idiot I am" 🙄

[numskull]

5 hours ago, xman said:

If I ran out of fuel, I would probably think "What an idiot I am" 🙄

Me too!

[J.R.]

Well this idiot drove 1040 kms today, a different route but autoroute all the way, longer than I had thought and after half a tank it became apparent that I would be probably 40-50 miles beyond what I believe the maximum range is (change of units for you there!).

 

Fuel light came on, ignored it and carried on for another 100 miles or so, zero miles remaining showed at 510 miles, on the way up I had done 525 miles with 25 remaining with the roof rack on - go figure!

 

Today I drove a further 50 miles on the Autoroute A20 with zero mile remaining displayed to get to a services at about the right place and did a splash and dash at 560 miles, 10 litres enough for the rest of the journey, no more because that alone was €2 more expensive than normal pump prices, display indicated enough range to complete my journey but of course then magicked it away so the last 50 kms were once again completed with zero miles remaining indicated, units changed to keep you on your toes!

 

So this idiot would respectfully suggest that only an muppet would believe the fuel guage or distance remaining on a VAG vehicle built in the last 25 years.

 

I would also suggest that the world would be a better place if people on social media were a little less judgemental, people do not have to provide an excuse for their decisions and level of risk aversion.

[xman]

4 minutes ago, J.R. said:

I would also suggest that the world would be a better place if people on social media were a little less judgemental

Great idea, you go first @J.R. 😂

[J.R.]

On 03/03/2024 at 15:11, Rooted said:

Unfortunates maybe.   I would like to hear the reasons some give.  Faulty fuel gauge and not familiar with the vehicles sounds OK.

 

I have run out twice, both times when the fuel sender was playing up on my MK1 Octavia and I had not kept an eye on the trip meter as a back up.

 

Both times I was returning from scuba diving where things did not go to plan so I was distracted/tired each time.

 

The first was driving 3 other divers back from Brittany, ran out on autoroute, coasted into service station and refilled but would not start and I did not know how to bleed the injectors which was not well recieved. I had been driving diesels a few years but till then they were just too darn reliable for me to gain any experience.

 

The second time was ice diving near Arras, passing between holes cut in the ice following a guide rope, I had forgotten my neoprene bootees so decided as it was a short dive I would do it in my socks and hiking boots and hopefully get some feeling back afterwards with the car heater, it was of course well below zero degrees, the last big freeze in Northern France, perhaps 2007.

 

15 minutes on the way back I ran out of fuel and had to spend the night in the car in my bivvy bag at minus 10°c with bare feet. The guage which I had repaired and had been working well got binned for another.

[xman]

2 hours ago, numskull said:

8 hours ago, xman said:

If I ran out of fuel, I would probably think "What an idiot I am" 🙄

Me too!

 

🤔 Not sure who you mean

 

😂