mileage from a tank of fuel??

[suep1972]

Filled up yesterday when at top of red (jumped out of my skin with warning beep). Had done 320 miles from full tank to top of red.

[KenONeill]

Thank you for all the responses!!

I do have a couple of other things now though,,,,

1 - why would 18" wheels differ the fuel economy??

2 - Yes i do service the car regularly, it has new plugs, air filter, oil and filter change, every 6 months, regardless of mileage

3 - The tyre pressures are checked every week and are always OK, apart from about a week ago when i got a puncture in the NSR :( but as i was changing the wheels and tyres anyway i didnt bother to get it fixed, it was only dropping about 2 psi per day so i just kept topping it up

(1) You will have changed the rolling resistance. However, if you haven't increased the tyre width, I'd expect rolling resistance to reduce, because of reduced sidewall deformation.

(2) That may be overdoing it a bit; plugs and air filter are normally good for 12_000 and 24_000 miles respectively.

(3) I've had similar, and done the same.

On the tyre pressure point, the best tyre pressure for the car may have changed now, due to the different size (and make?) fitted. As an example, several of us have fitted Toyo Proxes T1-Rs in standard size, and found they want a couple of PSI over OEM recommendation to prevent excess shoulder wear.

[RichB86]

i was chatting to a guy yesterday who brought up a good point about as the Oct has a small turbo as soon as you want to accelerate the turbo cuts in and is using fuel, whereas with a bigger turbo it wont cut in till latter thus meaning your on the turbo less when just commuting so not drinking like an alchoholic.

[KenONeill]

Er, if you drive a car of given mass and gear ratios, and want to accelerate at a ms^-2, you require a certain amount of power, irrespective of how big your turbo is(n't). A small turbo spools up faster, meaning that you get that power sooner, so you'll be on the throttle for less time, so the small turbo car actually uses less fuel in stop/start or give and take driving.

[v8rick]

(1) You will have changed the rolling resistance. However, if you haven't increased the tyre width, I'd expect rolling resistance to reduce, because of reduced sidewall deformation.

(2) That may be overdoing it a bit; plugs and air filter are normally good for 12_000 and 24_000 miles respectively.

(3) I've had similar, and done the same.

On the tyre pressure point, the best tyre pressure for the car may have changed now, due to the different size (and make?) fitted. As an example, several of us have fitted Toyo Proxes T1-Rs in standard size, and found they want a couple of PSI over OEM recommendation to prevent excess shoulder wear.

Thanks,, i know the air filter and plugs thing might be a touch over the top, , but then i figure there is no harm in treating it to new goodies every now and again, .

I have since had the car plugged in to the VAG thing, and found,,,,,,, one or two problems,,,, erm,, where do i start:D

1 - MAF sensor faulty

2 - Lamda sensor Faulty

3 - Engine temperature sensor faulty

4 - Cylinder 3 misfire

5 - Random misfire

oh yes, and several breather hoses frayed and split (hanging off in places too )

Put new MAF sensor on and new temp sensor, and replaced all hoses, new plugs,,,, again,,,,, and new leads, already getting 40 miles more from tank,, and pick up and overall response FAR better now, getting plugged in again tomorow to see if lamba fault has gone due to correct fuelling now, if not then new one of those tommorow too,, :( LOADS OF MONEY!!!! :(

[Babs]

Er, if you drive a car of given mass and gear ratios, and want to accelerate at a ms^-2, you require a certain amount of power, irrespective of how big your turbo is(n't). A small turbo spools up faster, meaning that you get that power sooner, so you'll be on the throttle for less time, so the small turbo car actually uses less fuel in stop/start or give and take driving.

What about constant speed/throttle opening then? Surely the engine won't be "on boost" as much so will be producing less power...? Maybe?

[Malc]

400+ miles without fail and I don't hang about but my driving is mostly cross country, minimal traffic and not much stopping - result

[Steevie Wonder]

300 pottering around town with the odd run out.

I got 420 doing Birmingham to Portsmouth to Kendal not so long back..... but I can cruise rather nicely at a fair lick....if you know what I mean;)

[martziniuk]

Damn you steevie with your six speed diesel gearbox

[KenONeill]

What about constant speed/throttle opening then? Surely the engine won't be "on boost" as much so will be producing less power...? Maybe?

If you're off-boost, you're off boost, irrespective of how big your turbo is.

If the boost's coming in with the small turbo you'll use more than with the big turbo that's still off-boost.

When the boost's coming in on the big turbo and the small one's on boost, not sure.

When both are on boost, you've more potential to be making power that you're not using (because you're not accelerating) with the big turbo.

[ocdavia]

My low fuel warning buzzer comes on at approx 490 miles with the needle just on the edge of the red.What confuses me is that when i fill up, i only get about 45 litres of fuel in, so does that mean that ive still got around 10 litres left? If i have then i could get nearly 600 miles out of a tank (this is mostly 70mph+ dual carriageway driving)

[KenONeill]

That sounds about right for a 90 on legal speed dual cabbageway work.

[Seedy Jay]

Managed over 400 miles for the first and only time (well, 410 to be accurate), range of about 20 miles before i filled up. Mix of country/town driving boosted with 180ish m'way miles sitting at about 70 :zzz: cos the tank was a bit low. God, was it ever dull! 350-360 normally off a tank (4x4, that is).

[Lofty]

My 110 tdi does at least 550 to a tank full. I know that because that my weekly mileage comuting to and from work (just over 100 per day), mixture of a roads and country lanes.

Last week on a family holiday to devon it was averaging 62mpg all week, and the computer said the tank range was 650 miles!!

Just out of interest, how accurate are the trip computers in the Octavias?

I must say, compared to my last diesel (306 hdi 2.0 90bhp) its a much more fuel effiecient car, plus much nicer to drive.

[KenONeill]

My 110 tdi does at least 550 to a tank full. I know that because that my weekly mileage comuting to and from work (just over 100 per day), mixture of a roads and country lanes.

Last week on a family holiday to devon it was averaging 62mpg all week, and the computer said the tank range was 650 miles!!

Just out of interest, how accurate are the trip computers in the Octavias?

I must say, compared to my last diesel (306 hdi 2.0 90bhp) its a much more fuel effiecient car, plus much nicer to drive.

I'd say the "mpg" modes are about 10% optomistic, which is bizzare because I reckon the "available mileage" mode is pretty accurate as long as you don't try and use it in the first 10 minutes after starting a trip.

I'd agree about the "much nicer drive" comments too, compared with my Xantia XUDt.

[daveslp]

on my 90 TDi i get atleast 530 with small bit of messing but with granny driving close to 600!

270 from a 2l? how could you afford to run that as an everyday fam car? i have my Golf GTi for the fun:)

[sms]

ok mine is an octy 2 but i can get 30-40mpg on the 8 mile drive to work (from cold). yesterday we did a journey to swindon then oxford then home again and averaged 44mpg and the trip up to the lakes the other week got around 46mpg in all different styles of traffic imagined and all from a 2.0 petrol (non turbo).

[simonlb]

on my 90 TDi i get atleast 530 with small bit of messing but with granny driving close to 600!

Strangely enough I've been keeping a record recently of the mileage done and fuel used each time I fill up. With my normal driving I'll get between 540 -550 miles before the fuel warning light comes on. Going off that, 620 miles or so is achieveable, but on a long run I suspect over 700 miles may be possible.

[gixxaboy]

I tanked up outside Nurburg and the fuel light came on before Watford Gap services...........keeping a nice steady 75 ish, motorway all the way. I thought that was quite good. 470 miles? I wasn't getting that out of a diesel. No air-con or cruise control used tho', trip showed 43mpg.

After the re-map did EuroDisney easily fully loaded this time with luggage and children and showed 43mpg. On the way back from JabbaSport after the map it was reading 46mpg at steady motorway cruise, but only me and sod all else on board.

Drive it like I stole it and it pours out of the exhaust like a V8:rofl:

[Aidan]

VRs on a regular commute on single and dual carriage way and get over 400 miles a tank. A consistant 40+ mpg calculated but computer says between 40 and 45 over that distance

[RobClubley]

VRs on a regular commute on single and dual carriage way and get over 400 miles a tank. A consistant 40+ mpg calculated but computer says between 40 and 45 over that distance

You must be a very gentle driver!

I managed 700km (437miles) on a long run doing a more-or-less constant 60 on NZ roads (much like UK A roads).

On shorter trips around town I average about 500km (312 miles) on a tank.

[pikpilot]

I have kept a record of every drop of fuel since I bought the 110 TDi Octy 1 last October.

Most of my journeys are around town with a heavy load in the boot.

Average mpg has been 44.56 over 4146 miles with a low point of 40 (cold weather without the engine getting hot) and a high of 50.4 on a long motorway journey.

All figures are from roughly 30 miles left in the tank to refill to the nearest whole litre after the filling pump cuts off.

You can see the variation in each tank full on the chart as well as the pretty consistent average.

Miles per tank varies between 417 and 499 with an average of 460.

Octy mpg.doc

[Octavia Vrs!]

My Vrs has done just under 400 miles on a good run but at the nurburgring has emptied a FULL tank in 4 laps!

54 miles. Full to empty in less than 40 minutes :eek:

[RobClubley]

My Vrs has done just under 400 miles on a good run but at the nurburgring has emptied a FULL tank in 4 laps!

54 miles. Full to empty in less than 40 minutes :eek:

:eek::eek::eek: Impressive!

My worst ever was a trip computer reading of 6mpg from Bradford to Leeds in appalling queueing traffic.

[athol]

560 miles with neddle just above the red line is the best I've had, and also lowest I've had. check it each time I fill up, 56-57mpg is my normal in 1.9TDi 90bhp with mixed driving on mixed roads. my Cordoba diesel was doing 45-47 and I thought that was good !

Octy a much better car to drive and much more comfy as well