Better Figures then 900kms to a tank

[polo_spec_d]

After getting back from my holiday I crunched some numbers on my fuel consumpion, 3.75L/100kms, This was a combination of city and hwy driving, but mainly hwy.

I was pretty happy with these figures even more due to that I was doing all my driving in the middle of the day and got caught in peak hour for somke off it too.

Anyone else in the 1.9TDI seen figures like these before?

NB. car still isnt empty so I could drive abit more if I wanted, But unsure if I wanna run out.

[Mofo]

That's sensational, even for the Polo.
I've got the Golf 2.0 TDI and the best i've ever gotten is 4.5 overall, that's all highway driving with virtually no peak hour to contend with. I just can't seem to get any lower than that no matter whether I cruise at 100 or 115!
What mods have you made to improve your economy?

[polo_spec_d]

only engine mod I have is the Seat Intake. Ohh and I was running on the eco conti tyres.

[Mofo]

very impressive. I may need to look for my own polo, I'm very much interested in the fuel efficiency side of things rather than the performance.

[polo_spec_d]

ohh the polo offers both IMO. most off the time most performance mods get you better efficiency to a point, I have read (sorry cant remember the webpage) polo 1.9s getting like 3.1 and even going under 3L/100kms with strict driving practices and fuel saving mods.

[gregozedobe]

Well done on getting some good consumption figures.

Just a thought, was your consumption based on the trip computer or calculated from fill to fill ? My Transporter's MFD is always optimistic, sometimes to the tune of over 20% ! Even a single fill calculation can be slightly inaccurate, as it is difficult to fill a diesel to exactly the same point each time (all that froth). I tend to use an average of at least 3 fills, so it evens out a bit.

But it is fun to sometimes see over 1,400Km as the "Distance to Empty" (not that I believe it) :)

I get my best ecomomy on dry roads when it is around 22-25C. I get more power when it is cooler, but use more fuel.

If I am prepared to sit on 80Kmh on flat roads I can coax my MFD to show 4.5l/100Km in my transporter, but it is so slow I am in serious danger of getting run over from behind (also it seems to take forever to get anywhere).

[polo_spec_d]

I dont have a trip computer unfort, the car was dead empty when I filled up, It took 45L no more. this was the first time its ever been that empty. the car was shuttering as I came towards the servo.

When I was on the open road I sat on 105km/hr. I was just so suprised to get those kind of figures with it been so hot.

[Pumpe-Düse]

I don't see how that is possible? Driving my MY08 1.9 TDI Sydney to Canberra and back in one night, 100% highway, yeilded 4.94L/100km. If your car was a Bluemotion....

How many km did you travel and how many litres did you put in?

[Transporter]

I don't see how that is possible? Driving my MY08 1.9 TDI Sydney to Canberra and back in one night, 100% highway, yeilded 4.94L/100km. If your car was a Bluemotion....

How many km did you travel and how many litres did you put in?

It is possible why not?

But you forgot to mention the speed you were going when you got only 4.94L/100km?

Just a few things that affect fuel economy:

Keeping the speed around 90km/h (105km/h on Polo clock could be 95km/h in reality)
Aerodynamics
Outside temperature, humidity
Tyre pressure, type and condition
Flat long roads or hills.
Stop start
Weight the car is carrying
Mechanical condition of the car. ( if new are there any modifications?)
And the most important is the driver's experience and knowledge how to achieve the best fuel economy

[neil]

Figures should be possible.

MY08 Jetta TDI 2.0
Trip from Central coast to Southern highlands @ 100km/h 4.5L/100
However the return trip Basically identically can be done at 3.9L/100
Depends on the road conditions, Down hill back to Sydney
Also found some improvements with increased tyre inflation at 40psi

Before increasing the tyre pressure my consumption to Highlands was 4.6

also no aircon on on any trips.

New audi 1.9 has a manufacture figure of 3.9 on the label.
7 speed DSG and roll resistance tyres.
So potental for better consumption than this you would think.

[polo_spec_d]

It is possible why not?

But you forgot to mention the speed you were going when you got only 4.94L/100km?

Just a few things that affect fuel economy:

Keeping the speed around 90km/h (105km/h on Polo clock could be 95km/h in reality)
Aerodynamics
Outside temperature, humidity
Tyre pressure, type and condition
Flat long roads or hills.
Stop start
Weight the car is carrying
Mechanical condition of the car. ( if new are there any modifications?)
And the most important is the driver's experience and knowledge how to achieve the best fuel economy


I kept to 90km/hr on the hilly sections (40kms) and 105km/h which as you said is around 95km/h, I do have coilovers fitted to the car and lowered them to a correct height that wouldnt put handling and ride out of wack.

Humidity wasnt much of a factor as the heat here on those days was fairly dry heat.

Tyre pressure was increased to 35psi from 33psi and the tyres are in good condition. (only 15,000kms on them) The eco conti that come on the polo.

The car was carry 1 passanger and 2 over night bags, so not much weight there.

Only engine mod is the SEAT intake, but I would imagine lowering the coilovers would help with aerodynamics abit??

And last but not least is driver experience. Well I do alot of driving for work in a Isuzu NPR 200, mainly country driving as I work away through out WA and I must drive to alot of those places. I learnt from many drives that Big Semi's and other smaller trucks can be your friend when it comes to these long drives.

I used other road users infront of me to help gain this figures, But you dont get something for nothing and I help them out aswell with getting in front of them and breaking the wind.

Transporter you are very much right with the factors there.

I think it was a good idea of Transporter to list the factors, Now people have if not already on the forum a list to work with when planning long trips.

[Pumpe-Düse]

It is possible why not?

But you forgot to mention the speed you were going when you got only 4.94L/100km?


110km/h on the speedo, the whole way.

So spec d, how many km travelled and litres put in?

[polo_spec_d]

When I filled up before the trip I put 45.05L into it, and I have travelled so far 1100Kms. The fuel light is on so now its just a waiting game to when I wanna fill her back up.

When I go fill it up I post how much it takes.

[VW Convert]

I dont have a trip computer unfort, the car was dead empty when I filled up, It took 45L no more. this was the first time its ever been that empty. the car was shuttering as I came towards the servo.

When I was on the open road I sat on 105km/hr. I was just so suprised to get those kind of figures with it been so hot.

Not doubting your word or anything but if I'm reading this correctly, you got 900+ KM from a tank, you calculated 3.75L/100KM and you refilled with 45 litres? The sums don't add up, at 3.75L/100KM you would travel 1,200 KM on 45 litres.

Am I misunderstanding what you are saying or have you miscalculated?

Cheers

George

[polo_spec_d]

I havent filled up yet from that tank yet, Still going haha. when I put 45L into it was at the start of the drive.

[VW Convert]

I havent filled up yet from that tank yet, Still going haha. when I put 45L into it was at the start of the drive.

Better than 1,100 km on a tank is great, but how do you calculate your consumption if you haven't refilled?

Cheers

George

[polo_spec_d]

Well from what I put in and using the fuel gauge, eg. quarter of a tank is 11.25L, on that first quarter I gathered roughly, give or take 30kms or so 300kms. then measured the next two quarters and came back with the same figure. From what I have donw so far on the last quarter of the tank in heading to 1200kms but ill fill up 30kms short of that to see what the tank takes.

At that stage I did the calcs to return the figure 3.75L/100kms, I know this does seen very spot on but has work wonders when I cant use a MFD.

[VW Convert]

Well from what I put in and using the fuel gauge, eg. quarter of a tank is 11.25L, on that first quarter I gathered roughly, give or take 30kms or so 300kms. then measured the next two quarters and came back with the same figure. From what I have donw so far on the last quarter of the tank in heading to 1200kms but ill fill up 30kms short of that to see what the tank takes.

At that stage I did the calcs to return the figure 3.75L/100kms, I know this does seen very spot on but has work wonders when I cant use a MFD.

That's not an accurate method because the gauge may not be as accurate as we would like it to be although no doubt you are getting great mileage. What you need to do is fill it up and do the calculations based on distance travelled and the amount of fuel it takes to refill it, then you have an accurate figure.

Will be interesting to see how it pans out.

Cheers

Edit. A word of caution, running your diesel out of fuel can be very detrimental for the fuel system, the fuel cools and lubricates things like the injectors. You should keep this in mind and not let it run too low.



George

[Transporter]

I kept to 90km/hr on the hilly sections (40kms) and 105km/h which as you said is around 95km/h, I do have coilovers fitted to the car and lowered them to a correct height that wouldnt put handling and ride out of wack.

Humidity wasnt much of a factor as the heat here on those days was fairly dry heat.

Tyre pressure was increased to 35psi from 33psi and the tyres are in good condition. (only 15,000kms on them) The eco conti that come on the polo.

The car was carry 1 passanger and 2 over night bags, so not much weight there.

Only engine mod is the SEAT intake, but I would imagine lowering the coilovers would help with aerodynamics abit??

And last but not least is driver experience. Well I do alot of driving for work in a Isuzu NPR 200, mainly country driving as I work away through out WA and I must drive to alot of those places. I learnt from many drives that Big Semi's and other smaller trucks can be your friend when it comes to these long drives.

I used other road users infront of me to help gain this figures, But you dont get something for nothing and I help them out aswell with getting in front of them and breaking the wind.

Transporter you are very much right with the factors there.

I think it was a good idea of Transporter to list the factors, Now people have if not already on the forum a list to work with when planning long trips.

That is very good fuel consumption, since you were doing 110km/h at some stages I found out that when I kept the speed at 100km/h fuel gauge read 5L/100km steady, with 2 people in the car and empty boot, but driving at the night through the Adelaide with not many stops at the traffic lights I could get 4.1L/100km on the trip computer and it is 0.25L optimistic when checked against the fuel docket. So it might be better to drive less than 95km/h to get better fuel economy.
I don’t get to drive our Golf very often, so I can’t reliably tell what is the best speed in TDI Golf/Polo to get the best fuel consumption.

Ideally if you want the best fuel economy you need to plan your trip as early in the morning as possible and also humidity is the fuel economy friend since the water in the air turns onto the steam when heated up in combustion and you get extra push on the pistons. Remember that every time you don’t touch the accelerator pedal there is 0 fuel injected.:)

[polo_spec_d]

Well I filled up this arvo, got to 1150Km and thought I better fill up as running on that mucky stuff at the bottom of the tank cant be good for the engine. and the car took 44.3L.

So not as empty as before I started the trip.

[geoff_gti]

So about 3.85L/100 then if I've got it right? That is quite impressive!

[polo_spec_d]

Yeah thats right, pretty good I reckon, hmmm maybe long range tanks......

[silvershadow]

I filled the Eos on Christmas Eve to check the fuel consumption for the first time [MY09 TDI common rail DSG].

Distance travelled: 815 Km

Fuel used: 46.2 litres

Fuel consumption [metric]: 5.67L/100km or 17.64Km/litre

Fuel consumption [imperial]: 49.8mpg [imperial gallon]
41.5mpg [US gallon]

This was achieved with a mix of 80% country, 20% city driving with the A/Con on for about 50% of the time [the roof was down the other 50% - the car is the best drought-breaker ever, plan to take it out and it will rain every time] :frown:. Best instantaneous fuel usage figure on the trip computer observed so far is 4.1 L/100Km at constant 80 km/hr for 20Km due to roadworks [A/c on]. The effect of the airconditioning system appears to be around 0.2 L/100Km extra at speeds in the range 80/115 Km/hr.

Very impressive and will get better as the engine frees up [2400Km on clock so far] - diesel technology improvements now make the TDI a worthy alternative to be considered.

[blutopless2]

Remember that every time you don’t touch the accelerator pedal there is 0 fuel injected.:)

not quite... still need fuel to keep the motor running.

[gregozedobe]

not quite... still need fuel to keep the motor running.

not not quite, actually :) - Transporter is 100% correct - there is actually no fuel being injected when on the over-run ie the momentum of the car is keeping the engine turning over. So when the MFD says 0.0 l/100km it is exactly that. The injectors will start injecting fuel again when the engine is approaching idle speed to stop it stalling.

So if you time your run right you can back off as you approach a red light, and you are using no fuel whatsoever on the run up to the light. This helps fuel economy.

There are some that debate that if you lift off too soon you have to your foot on the accelerator again to stop slowing down too soon and this uses more fuel than putting your car into neutral and coasting in with the engine idling, and the even more extreme will switch their engine off (but I think that is crazy stuff, and totally inappropriate for driving on public roads :eek:).

[Transporter]

not quite... still need fuel to keep the motor running.

Ok, when you decelerate the fuel delivery is 0.
Remember it is a diesel engine.:)

[blutopless2]

there is actually no fuel being injected when on the over-run ie the momentum of the car is keeping the engine turning over.

thanks for the correction.
Is it only the diesels that do this?

[gregozedobe]

Is it only the diesels that do this?


Exactly the same for TFSI petrols as well - no point injecting fuel if it isn't needed. The only down side I've noticed is in a very slow moving traffic jam - your accelerator foot can get a bit confused with the injectors starting up again at near idle speed.

[Vicbitter]

I don't see how that is possible? Driving my MY08 1.9 TDI Sydney to Canberra and back in one night, 100% highway, yeilded 4.94L/100km. If your car was a Bluemotion....

How many km did you travel and how many litres did you put in?


Maybe the car isnt run in yet, how km's on the clock have ya got?

[Mischa]

this is the best i've gotten from a tank. it was 90% highway and average speed probably 110. the other 10% was fanging it through melbourne lol.

http://www.vwwatercooled.com.au/forums/images/imported/2009/01/P281108_1833-1.jpg

[Vicbitter]

How big is your fuel tank?

[Mischa]

How big is your fuel tank?

mine? 55L. as far as i rememeber it had only used 52 litres.

[Golf Loon]

I did Gold Coast to Brighton Le Sands and back to Camden on one tank in a T4 TDI 2.5L. Doing 140 most of the way. That was over 1000ks.

[Vicbitter]

Nice...
I got 52 litres, and currently geting about 600kms.

-Heavier car (1560kms)
-Still running in
-Thats mixed (highway/urban)