78.8mpg. Audi A2 2005 1.4tdi

AudA2Numpty

A2OC Donor
As I have said on this Forum before, I just like to enjoy a journey at reasonable speed and not to become obsessed with eking-out every every last drop of fuel. I have, however, taken to "free-wheeling" a bit, recently. I am surprised how easily the car progresses with little drop in speed! And my DIS shows a slight improvement in average mpg ... I think that even if my life depended on it, I couldn't get these ultra-high mpg's! Over 80 mpg ??!! I wonder what the ideal cruising speed might be, for best mpg? 50-55 mph? That would be almost unbearable to me! The only way to accurately check the mpg is true "brim-to-brim" Maybe some mistakes might have been made in making these incredible mpg claims?

David
The last tank of fuel I input was definitely a full tank used so the next one will be the same as per your suggestion.

I'm now letting my wife have the car for a week to see the difference in mpg of driving styles.
I'll make sure she uses the full tank.

I have checked the cars speedo with my iPhone gps and our TomTom gps. They both read the cars speedo being 3mph slower than the seedos indicated speed.

I assume that is an acceptable tolerance?

I don't think I have made a mistake in writing down my mileage vs price paid for fuel and quantity of litres filled. I have been doing this for a while with the other vehicles I've owned but there always is room for human error.

Hopefully I am getting the mpg Roadtrip and fuelly say I'm getting, I'm not sure why having to user all of my fuel to test my true mpg matters but I'm keen to give it a shot for the sake of argument.
 

timmus

A2OC Donor
As I have said on this Forum before, I just like to enjoy a journey at reasonable speed and not to become obsessed with eking-out every every last drop of fuel. I have, however, taken to "free-wheeling" a bit, recently. I am surprised how easily the car progresses with little drop in speed! And my DIS shows a slight improvement in average mpg ... I think that even if my life depended on it, I couldn't get these ultra-high mpg's! Over 80 mpg ??!! I wonder what the ideal cruising speed might be, for best mpg? 50-55 mph? That would be almost unbearable to me! The only way to accurately check the mpg is true "brim-to-brim" Maybe some mistakes might have been made in making these incredible mpg claims?
Living out in Prestatyn, you're ~25 miles away from the nearest motorway. I know you're on the doorstep of the A55, but the A55 is dotted with roundabouts at regular intervals, meaning it's not great for economy driving; you're forever burning fuel to gain some momentum, only to have to give it all up again. So, your location within the country is bound to have an impact upon your ability to get 'high scores'.
I don't know how you use your car. Is it used regularly for short journeys? I also don't know how you drive. I appreciate that you like to progress at "reasonable speed", but that doesn't say much about how you drive in rural and urban environments? My dad will keep his foot on the accelerator until he's within a relatively short distance of a junction and then hit the brakes rather than anticipate and engine brake. Do you also drive like this?
For all that I enjoy beating my own economy record when I do a long-distance run, I'm not at all obsessed with economy driving on a day-to-day basis. I enjoy my car for all its personas, and will happily have some fun with my car when the mood takes me. But good eco habits are totally integrated into my driving style. For instance, even when I'm having fun bombing it along country lanes, I'll still in-gear coast to lose some momentum when approaching a sharp bend rather than use my brakes. MikeMars spends almost every minute behind the wheel concentrating on his fuel usage, which I certainly do not do, but yet I rarely average less than 60mpg. My car doesn't have DIS, so all my figures are worked on a brim-to-brim basis ...and I definitely haven't been making mistakes in my calculations. :)

Tom
 

DJ 190

A2OC Donor
I know you're on the doorstep of the A55, but the A55 is dotted with roundabouts at regular intervals

Tom
Well, you can't have travelled the A55 much then? There are no roundabouts at all in the Manchester direction. Continuous 50 mile trip to Cheadle exit! Going in the Anglesey direction, the first roundabout is at Llanfairfechan, about 23 miles away! I think that there is only one more (or maybe it is the only one?) My driving style is definitely "gentle" I am not a spirited driver and I don't think I've ever "floored" the accelerator! I certainly have never needed to use the cars full potential .... That is North Wales for you ... relaxed! I do not recall ever using my horn, either! Oh, that A55 is only about 3 km from my home, so I'm soon on it .... I seem to be getting 52-55 mpg recently.

David
 

timmus

A2OC Donor
Well, you can't have travelled the A55 much then?
I've travelled it plenty of times, though only ever to go all the way out to Anglesey. I seem to remember that there are sections where the roundabouts seem endless, but it's clearly well past Prestatyn from what you describe. Maybe I remember there being more of them than there actually are because they wind me up!? Either way, never mind.
Whether eco drivers or not, we all have to accelerate. Some people choose to do it gently, but some eco studies have suggested that it's best to get up to cruising speed quickly. I made little mention of it in my previous post because the way you go about losing momentum is of greater importance. My dad thinks he's a gentle driver (and he is), but that doesn't stop his habituated driving style from wasting fuel.

Tom
 
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Dblock

Member
You coast with the engine idling, as opposed to being in gear? I do both, but seem to get better results in gear, using engine braking. I believed this was due to the engine not using fuel, as it does when idling...
That is true but it does depend on what your doing. When coming home from work and I'm no rush I'll do pulse at glide. I'll accelerate hard to 70mph and then clutch in till I'm at 55 and then boot it until I'm at 70mph and clutch in. This sounds like a waste but honestly its more efficient than driving at 60mph constant due to efficiency at high loads etc. If I left it in gear the car would slow down much much quicker making it not much use.

The "cutoff" is when the car uses no fuel and does have it use but so does clutch in. I.e Sitting at idle going no where 0mpg. Sitting at idle going 70mph = lots of mpg. When slowing down maybe do a bit of both and see which you prefer but cutoff uses no fuel apparently making it better but as I said it will slow the car down very quickly.
 

dan_b

A2OC Donor
David, is your thermostat working correctly I wonder. If you're in the low 50s but driving as gently as you say, perhaps there's a gremlin.
 

Birchall

Dick Chown Award 2016
Is it me or isn't all of that just too much bother?

Great to try it out to see what the maximum MPG you can get, but surely for normal motorway driving it is far too unnatural and could even be distracting and may even cause other drivers to have to change lane as you slow down?

The "accelerating hard to 70" destroys your MPG figures. When you are accelerating the engine is at its least efficient. surely it is better to accelerate gently for slightly longer than a hard acceleration.

Everyone has a theory and I am not going to challenge anyone's theory, I am just stating my theory, and so I may be getting it wrong.

But one thing I am sure of is that when I drive I focus on driving smoothly and safely.

Steve B
 

johnmed

A2OC Donor
Very true. I have a scangauge installed to show me the REAL coolant temperature. I don't know about the a2 but generally all cars lie about the coolant temp. When in the middle my car shows about 70c and it took ages to get up to that. After some grill blocking it heats up much much quicker and will get to 88-89c after a little while on the dual carriageway.

I hope to get cruise control fitted and a longer 5th to nudge up my economy.
I'd be interested to see how you've gone about grille blocking, having seen Hackney cab drivers do this for years.
 

Dblock

Member
I'd be interested to see how you've gone about grille blocking, having seen Hackney cab drivers do this for years.
I used a bit of lino. The seats use a crosshatch grill rather than vw style slats. So I lino'ed it with cable ties. Does the job. I recenlty replaced the thermostat. With my scangauge I can see what tempreture the car is really at. Most before was 60cish and now it's high 80c's even when cold.
 

Dblock

Member
Is it me or isn't all of that just too much bother?

Great to try it out to see what the maximum MPG you can get, but surely for normal motorway driving it is far too unnatural and could even be distracting and may even cause other drivers to have to change lane as you slow down?

The "accelerating hard to 70" destroys your MPG figures. When you are accelerating the engine is at its least efficient. surely it is better to accelerate gently for slightly longer than a hard acceleration.

Everyone has a theory and I am not going to challenge anyone's theory, I am just stating my theory, and so I may be getting it wrong.

But one thing I am sure of is that when I drive I focus on driving smoothly and safely.

Steve B
Maybe its too much bother but I don't really have much to do when driving home and if I had extra money I'd be happy.

The car has the highest efficiency at load. SO e.g. We both accelerate from 30-70mph. You take 30-35seconds with 30% throttle. I take 15-17seconds with 85-95% throttle. I've been on the throttle less time than you and because the car is more efficient with higher load the net fuel used is LESS. Completely made up numbers there but just for comparison. So it's not a theory but proven by many people. Try it you might find its not for you but you might like it.

here is a video. I usually drive 70-55 but this guy is driving faster where ever he is.

[video=youtube;a3vGliIbnMU]http://www.youtube.com/watch?v=a3vGliIbnMU[/video]
 

AudA2Numpty

A2OC Donor
that seems to be what I do in terms of technique except my car readout would be reading much slower deceleration for distance travelled, most of the time I use this technique the car stays at or accelerates a little all the while the car is in idle.
I never employ this technique uphill or if I notice a lot of deceleration like in this video.

My thermostat and temp sender had just been replaced by Tony at A2 cars and I can vouch for genuine parts to be used.
Prior to this work being done my car was returning 50 mpg, which was a dissappointment.
 
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Isnt this basically what the 1.2 tdi does with its gearbox?

It will do yes, in eco mode when you lift off it declutches & coasts. On A/B roads you can do this without really thinking about it, a little planning ahead to make use of your kinetic energy etc. On a motorway no chance!! that would be sooo annoying.
 

AudA2Numpty

A2OC Donor
Well I did it and I didn't have to take out the rear seats!

82.5mpg So pleased.

Any time the mpg is low either the wife was driving or the car has been in for service and has been road tested.
So I must have the magic touch. Either that or the cruise control which has been fitted did all the work for me?

Some lady reversed into it while I was in Scotland, luckily just a few scratches.

I'll be heading back up to Scotland soon to break my 82.5mpg record! Yey.
 
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There is no one else I can share this with as my wife just gives me that "really, seriously?" look.

I thought the first time I got 77.4mpg was a fluke but today I filled up after an almost 600 mile one tank drive from the Fraserburgh (Scotland) to Lake District to Clevedon (Bristol) and just beat my personal best by 1.4mpg to get 78.8mpg.

I'm now the best in my class on fuelly, whoohooo.
Though that's not saying much as there is only 11 of us there. :-(

Is this good for a 1.4 TDI?

Maybe it was something Tony at A2 cars did?
If it was, thank you Tony!
Crikey how did you achieve that.? Its incredible. Since buying my A2 TDI sport 4 weeks ago economy is improving but I'm no where near that figure...yet!
 

AudA2Numpty

A2OC Donor
I have no idea. I drive on the motorways at around 65/67mph (with the occasional speed pass the odd dodgy truck moment) the only main thing I tend to do is coast up to roundabouts/junctions/traffic lights, or coast downhill when I see a big one. If I know I'll be stopping I coast up the the point I have to stop.

Other than that nothing special. The car is semi full of stuff, never empty. the tyres pressures are on the 2.6 side and I have 15inch wheels with relatively good tread.

That said, the 82.5 was all motorway driving and 8 degrees outside temp. I didn't coast or anything. It was all cruise control. I was amazed when I filled up too. :)

I rarely clean the car and have no mods to the car other than the cruise control fitted by A2 Cars. oo one thing, something Tony from A2 cars suggested was to put Redex diesel cleaner in.
I misread the bottle previously and had only been putting in a tiny bit, there are notches on the plastic bottle and I had only been putting in one notch at a time. When I re read the bottle instructions it said to put in half (at least double what I had been putting in) the bottle. So on that day I put in half a bottle. Maybe that helped?
 
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Ricardo

A2OC Donor
Cruise control won't give the best fuel consumption. The trick is simply to tow lorries (higher lorries the better) and pick up speed downhill to use as little throttle as possible up hill. Constant speed doesn't do it. You need to overtake the lorries and pick up speed down hill, then freewheel up hill as much as possible before nipping in behind a lorry again. In an unchipped car 56mph is best because thats the speed the consumption figures are calculated for so usually the injection is optimised at this point for best economy by the manufacturers so finding a lorry trundling along at 56mph is the ideal. But above all don't brake or stop! .. if at all possible.

Using the above logic I have averaged 30mpg in a V8 S4 and 47.8mpg in a 2.0 petrol Alfa! Best I have seen in the A2 is 106mpg but that was only over 40 miles (up the M1 to Donington).

One thing that scares me when doing these consumption runs is to consider when you are averaging 70mpg and the range says 10 miles, and you are thinking "its OK I'm 5 miles from the fuel station" ... consider that there is only x2 cans of coke worth of fuel in the tank!!!

Another little tit bit is my A2's 40L tank, is actually about 43L including the lines... I got that from a trainer at Audi on a job I did, and as I have put over 40L in my car a few times I am inclined to agree with him.
 
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murdo

Admin Team
Cruise control won't give the best fuel consumption. The trick is simply to tow lorries (higher lorries the better) and pick up speed downhill to use as little throttle as possible up hill. Using the above logic I have averaged 30mpg in a V8 S4
Why you'd do this in a V8 S4 defies all logic! :p

Another little tit bit is my A2's 40L tank, is actually about 43L including the lines... I got that from a trainer at Audi on a job I did, and as I have put over 40L in my car a few times I am inclined to agree with him.
Yes, this has been spoken about a lot by the 'brimmers' on the forum eeking out the last MPG. The tank has a 42 litre stated capacity on newer A2's and theres some button you press with the filler nozzle inside the filler pipe which purges air and lets you fill the lines up too.
 
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Ricardo

A2OC Donor
Re: the S4, I was working on the launch event travelling to dealers to train them on the car and half way through the event when Audi worked out how much fuel we were using they decided to give us a fixed fuel allowance rather than a fuel card. So it became profitable to save fuel as they assumed 20mpg (we had been averaging 12mpg) so 30mpg made £££, even they were surprised it was possible lol.
 
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