Experimenting with fuel economy

[lil_coz]

Thought I'd put a post up on how things went! It never started off as an experiment, it just moulded into one.

Basically 2-3 weeks ago I drove down to the Isle of Wight. For me it's a shade over 200 mile round trip. When I left home, I had 3/4 of a tank worth of fuel and the trip down was mainly motorway. I averaged about 85ish on the motorway. I was basically flowing with the traffic in the fast lane. I kept an eye out in front and tried not to use my brakes, judging traffic etc and when I accelerated back up to speed, it was a gentle acceleration. When I got back home, I had 1/4 of a tank left. Now that impressed me considering how fast I was going. Theoretical range of 400 miles per tank.

Today I've come down to Southampton for a couple of weeks and again, it was 100 mile drive down so I thought I'd go on a proper eco drive down to see how little fuel I could use. I basically treated the throttle like a bruised testicle and the speedo never saw anything above 70 mph on the downhill sections. I spend most of the time doing between 55 and 65 mph.

The verdict? I used 1/4 of a tank. The same as before when I was going a hell of a lot quicker!

The only thing I can put the result down to was because I was going slower, I had to use more throttle to get up the hilly bits, where as when I was cruising faster the momentum took me up it. Got to say though, plodding along was quite a nice drive down with the weather as it was!

On a separate note, I think I saw a member come past me on the M3. It was a black A3 (could have been an S3) and their number plate rang a bell. It was KEZ **** (followed by 4 numbers). I was the one driving miss daisy on the inside lane

 

[audigex]

There's definitely an optimal speed for any car, and it's not always slower=better. That said, how accurate is your "Used 1/4 of a tank"? With a minimal amount of facetiousness, it's hardly a scientific measure.

Presumably, it's in 6th gear (higher gears = more efficient) but at the lower end of that gear, since drag is proportional to the square of speed (double the speed, 4x the drag). Then again, turbos are almost free extra power, so just below the turbo band and just inside it should be fairly comparable and not quite fit the rule, so 70mph at 2k rpm may not be significantly worse than 60mph at 1500rpm (just below and just above where the boost seems to kick in for me, numbers approximate)

I find that in my 2.0TDI (170) then I can get nearly 60mpg on a motorway/A-road trip, including a dozen or so roundabouts (slowing down to 20 or lower) and a couple of stretches where I either dropped to 40 in traffic or sped up momentarily to avoid getting in the way of someone coming up faster behind. That was over a distance of approximately 50 miles. I'm going to carry on experimenting though

Round town it definitely makes a significant difference - changing up as soon as possible (1800rpm) when I don't need to get into traffic gives me an extra 10mpg over 20 miles or so.

 

[lil_coz]

Oh it was by no means an exact science. The 1/4 of a tank was being full before I left and it was saying 3/4 when I got here. It was on the line for both. Today I had a look at the average MPG in the DIS and it said 37.7 mpg and an average speed of 57mph. No idea what it was the last time when I went down to the Isle of Wight.

That's my experimenting done. Lol It was just out of curiosity when I thought I'd go slower and see what happens. When you go slow you don't get the pop when the DSG changes gear lol :icon_thumright:

 

[batch]

Interesting read Coss, as much as I'm getting mine for a toy it's nice to save a bit of fuel and be economical sometimes! I managed to get one of the S3s I test drove onto a motorway and coming from my girlfriend's 206 (the VR is tucked up before I break it up) was amazing sitting at just over tickover in 6th gear! Sweet as...

 

[mjr901]

I just drove from Worcester to Luxembourg throughout the night last night in my S3 averaged 35+ mpg.

My shark map has really made my fuel economy better and loads more power. I used to get 22mpg on motorway runs! I have found best mpg is at about 60-65mph.

 

[Ash187]

look what i managed on a full tank in my 2.0 TDI 140

500 miles is not bad!

Before you say i just started driving...

managed that from not flooring it and driving nicely over a week with mixed urban and motorway driving

 

[_G_]

2.0 tfsi, 100 mile journey from warwick to west london... the computer said 28.6 mpg but i used a 1/2 a 1/4 (not good with fractions but I guess it is 1/8 of the tank)... drove at 75mph with econ (air con off) both set at 16 degrees... music on mid way... suitcase in the boot... tyres pumped up to the correct pressure... EXCEPT! on the way back the same journey took a full 1/4 this time... so that was just weird...

On the upside... the good news is... drove 100 miles to bristol from warwick on the same tank... down to 1/2 tank marker now... drove around Bath... and back to warwick and had 1/4 remaining... then drove to work all week... another 80 miles (20 miles a day)... Result! 480 miles out of a full tank... and enough to get to shell in warwick (the reserve light came on, on the a46).

Otherwise... 480 is the best and 360 on the tank has been the worse. Most weeks I usually get around the 420 marker.

most roads were flat though, not many hills or inclines and the weather was average around 7-8 degrees to london and back... the tank was v power, the car had been clayed etc so nice and stream line...

 

[jb0o]

No matter how I drive I always seem to be getting 340-360 to a tank on my 2.0T DSG

 

[FranA3]

Recently when i went to ultimate dubs i filled up did about 380 miles on half a tank most of it at 60mph doing average 53mpg I'm very bad a checking tyre pressures and things i do it every week without fail to make sure its the most eco driving

 

[quattro81]

I have not reset the av mpg since I got the car new(2.0tfsi stronic quattro) and I have managed an average of 19mpg over the last 15k maybe using the launch control all the time is not that economical..? Coupled with the fact that I agree with Jeremy clarksons - "allowing yourself to be overtaken is a sign of weakness" I'm never going to get close to reasonable figures

 

[VWAddict]

2.0T DSG.

400+ miles-per-tank, again and again:

Fourtitude.com - 400+ miles per tank (gasoline)

 

[hades-]

i know ur all a3
in the avant 140 i get around 700 miles on a tank motorway mostly avg 85mph

 

[FranA3]

i know ur all a3
in the avant 140 i get around 700 miles on a tank motorway mostly avg 85mph

that is impressive dude can't fault that at all can ya

 

[hades-]

thats why i got it
i do sheffield to barry every weekend so its 20 miles crap roads 190 motorway
can do 3 trips on the tank and a bit left

 

[mjr901]

the fact that I agree with Jeremy clarksons - "allowing yourself to be overtaken is a sign of weakness" I'm never going to get close to reasonable figures

I hear you buddy!!! 9 times out of 10....i'm in hot pursuit lol :busted_cop:

 

[FranA3]

thats why i got it
i do sheffield to barry every weekend so its 20 miles crap roads 190 motorway
can do 3 trips on the tank and a bit left

what barry as in south wales barry ??

 

[hades-]

yep **** hole that it is
it draws me back every weekend

 

[FranA3]

yep **** hole that it is
it draws me back every weekend

really thats mad I'm from barryshire lol , are you from there or visit family etc..

 

[hades-]

i made the mistake of doin a welsh bird she is a fit lil fukker tho
not a oem barry lass tho shes cowbridge an st athan
but we got a place on the waterfront so with my biz up here in sheffield i go back every weekend

 

[FranA3]

i made the mistake of doin a welsh bird she is a fit lil fukker tho
not a oem barry lass tho shes cowbridge an st athan
but we got a place on the waterfront so with my biz up here in sheffield i go back every weekend

that proves its a small world then doesn't it , you might even see me around barry if your there on weekends

 

[hades-]

i usaly let her drive when im there in a bug ah well
im always to ****** to care what im in

 

[FranA3]

i usaly let her drive when im there in a bug ah well
im always to ****** to care what im in

lol fair comment mate haha

 

[audigex]

I hear you buddy!!! 9 times out of 10....i'm in hot pursuit lol :busted_cop:

I've started basing it on who's overtaking me. If it's a Merc/Audi/BMW/Range Rover/Jag or any VW GTI, I let it slide, nobody else is allowed though. I let a Peugeot past the other day, I felt sick for miles.

 

[lil_coz]

look what i managed on a full tank in my 2.0 TDI 140

The highest I ever got in my 170 Quattro was about that. It was just on the one trip though... once in the 4 odd years I had it! Lol

I have not reset the av mpg since I got the car new(2.0tfsi stronic quattro) and I have managed an average of 19mpg over the last 15k

No idea what mines averaged as a whole. Done about 5k miles. Will have a looksy tomo!

I agree with Jeremy clarksons - "allowing yourself to be overtaken is a sign of weakness"

i know ur all a3
in the avant 140 i get around 700 miles on a tank motorway mostly avg 85mph

Flippin eck! That's impressive!

 

[xanderxxx]

well can you believe it?
i did a trip from Bristol to abbergavenny and back today with a few stops following M4, A449 and A40 i managed an mpg of 61.6 Tank range was 900miles .......................

(no passanger took the photo for me )

 

[audigex]

Xander, is that a 140 or 170 TDI (I'm gonna go right ahead and assume it's not a 2.0T)? I'm currently looking at a 600 mile tank with about half and half city and motorway driving.

Is it sad that I'm actually looking forward to a couple of long trips soon so that I can see what sort of MPG I can get?

500 mile round trip coming up soon. A bit short of cash atm so my targets are 35mpg+ round town, and to be hitting 60mpg on the motorway. If I can hit 55mpg average over the journey, I'll be happy

 

[xanderxxx]

hi its the 140 TDI chap dropped now to 675

 

[boroboy41]

My 04 plate 140 TDI averaged 45-46mpg over 7.5 years/98000mi and the range on a full tank was normally 450-500 miles. Most of that was just me plus some bags in the boot up and down the motorways cruising around 80-85mph. Would normally expect to be in the low fifties mpg-wise for +200 mile run.

Still waiting to see how the 170 TDI Quattro does on a similar journey but its done 36mpg on the school runs so far

 

[infernalzen]

hills make the main difference to my 170 quattro.
going to work, with lots of cars around +not holding back to driving miss daisy speeds, i get 39mpg.
on the way home on empty roads, where i can fully utilise anticipation +slowing down i can get 47mpg every trip.

that said, i let the speed decay going up hill +ease off on the throttle, instead of maintaining the speed (not something id do with other cars around)

i had looked at the differences between 140 +170 quattro mpgs before buying...
maybe next time with stupid fuel prices, i might have to lean more on economy for a 140

 

[xooo.co.uk]

104 BHP 1.6 TDI start stop S-tronic 7 speed

55 MPG round the doors
60 Motorways on cruise control

But not sure how 'run in' the engine is as its only done 1024 miles. but I'm half way through my second full tank of fuel

Massive difference to the old car which was an A4 2.5 TDI Multi-tronic battle beast.