TDi 90 economy.

KekseKaempfer

A2OC Donor
504 miles before the klaxon. I've got a good feeling about this tankful. :D Over the last 5 or so tankfuls I've been using Redex, although the average over these tanks is over 60mpg it doesn't seem to have made much of a difference. This tank, I didn't use Redex, and I think I may have beaten my record.

Very pleased
Chris
 

Crazylegs

Member
Well done mate, I take it you are driving normally as opposed to really frugally..

I just done 351 miles on £30 of diesel worked out 71.22MPG
I have never filled the tank up to full from empty before but may just do it on the next fill-up to see what I get!
 

KekseKaempfer

A2OC Donor
I couldn't wait until tomorrow to fill up. Just been to Asda. 34.5 litres, equals 65.2mpg. Which is my best ever.

Driving style is more on the frugal side of normal.

65 mph on the motorway, try not to go over 2500 rpm. Glide down hills where safe and engine brake up to junctions, speed limits.

I find it quite amusing, catching up to folks who have just whipped past me on the approach to a roundabout and then slammed on the brakes, as I gently arrive just in time to pull away again.
 

br1anuk

Member
Drove down the A55 from Liverpool to the Llyn peninsula in ours last weekend, speed was around 70/75 most of the way there and back and it averaged 55mpg on a 210 mile round trip. it absolutely flew up Rhault Hill, quite amazed at the torque in these small cars.
 

Crazylegs

Member
I couldn't wait until tomorrow to fill up. Just been to Asda. 34.5 litres, equals 65.2mpg. Which is my best ever.
Driving style is more on the frugal side of normal.
65 mph on the motorway, try not to go over 2500 rpm. Glide down hills where safe and engine brake up to junctions, speed limits.
I find it quite amusing, catching up to folks who have just whipped past me on the approach to a roundabout and then slammed on the brakes, as I gently arrive just in time to pull away again.
I normally stick to 56-60mph on motorways and change up as quick as poss around the houses, thats probably why I get 70+mpg since I have had the car!
 

terrywindy1

A2OC Donor
Travelled from Gloucestershire to Goodwood festival of speed yesterday in my Tdi 90 with 2 sons Went via Steves (birchall) near Heathrow
Motorway speeds 70mph + 10% = 62.8 mpg
I do use Shell V-power diesel and tyre pressure around 36 psi
This journey on my own at economy speed around 60mph would be around 70 mpg
 

MikeMarsUK

A2OC Donor
The TDIClub had a rule-of-thumb which (after translating for the A2's engine & US gallons) roughly equated to:

InstantaneousMPG = 130 - speed (at typical motorway / A-road speeds only). This seems to be consistent with the numbers above.
 

drewroberts

A2OC Donor
504 miles before the klaxon. I've got a good feeling about this tankful. :D Over the last 5 or so tankfuls I've been using Redex, although the average over these tanks is over 60mpg it doesn't seem to have made much of a difference. This tank, I didn't use Redex, and I think I may have beaten my record.

Very pleased
Chris
522.5 miles before the bing. I have been using a combination of slipstreaming lorries 55-60 mph (cheating), gentle acceleration and changing gear at no more than 2,500 rpm (annoying for some other drivers), gliding downhill and coasting (where safe to do so). Manual Stop/Start at level crossings, or if in heavy traffic. Tyre pressures (for 205/40/R17) as standard 30 front 28 rear (or other way round) No air-con used at any time, Front windows have been opened up to 3-4 inches on hot days. Redex was used on previous tank of fuel. Car struggles/labours a bit in 5th up inclines at 35-45 mph often needing a change down. So i am looking forward to see what a remap, and A2 fitted cruise does regarding that. Next thing to do is get 15 inchers and see if i can better it. I want to get as close as i can (eventually) to the 80.7mpg that Audi claim the TDi90 can achieve.
Still, i am very happy with the results so far.

Amazing, Underrated, Desireable, Irreplaceable.
 

John L

A2OC Donor
Isn't the A2 aerodynamically worked for efficient cruise at 120km/h?
This was stated in the original design brief anyhow: “Transport four people from Stuttgart to Milan on a single tank of petrol”.
How much worse is 70mph vs 60mph in an A2?

The speed limits here are too low to try but I have found that 90-100km/h has lower fuel burn than driving slower (50-70km/h).

The really nice thing with the TDi is that the passengers (and aircon) do not seem to ruin fuel burn as much as in other small cars.
I found when driving a Peugeot RCZ on UK motorways that going from 65 to 70 +10% as above caused the MPG to drop from the high 50's to 36-40.

I am looking forward to getting my car back and trying it on the Autobahn. This should allow me to log some data and get a good idea of speed vs fuel burn.

John
 

KekseKaempfer

A2OC Donor
Isn't the A2 aerodynamically worked for efficient cruise at 120km/h?
This was stated in the original design brief anyhow: “Transport four people from Stuttgart to Milan on a single tank of petrol”.
How much worse is 70mph vs 60mph in an A2?

The speed limits here are too low to try but I have found that 90-100km/h has lower fuel burn than driving slower (50-70km/h).

The really nice thing with the TDi is that the passengers (and aircon) do not seem to ruin fuel burn as much as in other small cars.
I found when driving a Peugeot RCZ on UK motorways that going from 65 to 70 +10% as above caused the MPG to drop from the high 50's to 36-40.

I am looking forward to getting my car back and trying it on the Autobahn. This should allow me to log some data and get a good idea of speed vs fuel burn.

John
This is quite interesting. This tankful, I've been averaging 70+ on the 20 mile motorway section without any particular heed to gliding or gear changes, and so far I've done 435 miles and am just below 1/4 full, so it seems that the difference isn't that much between my usual 60 -65 average. I have to say though I prefer being in the inside lane plodding along away from the reps in their beemers and A4+s
So I'll be back to normal speeds after tomorrow.

Chris
 

MikeMarsUK

A2OC Donor
... and am just below 1/4 full, ...
Beware that the gauge isn't linear, so it can be hard to tell on just part of a tank :) Although if I had to make a wild guess I'd say that 435@1/4 on a 42L tank is good and will end up being around 60-70mpg depending on how you fill up (either to the brim, or when the pump first clicks off, there is a gallon difference if you let the foam settle).


In my own experience, 'lowest reasonable speed in the highest gear' is the most efficient for mpg. However, if you always drive carefully the car will coke up after a while and the mpg will drop as a result. So it does need a bit of an 'Italian tune'* every now & then to keep it happy. This is particularly the case for the '90, which has a variable vane turbo.




* If it is coked up, find a long hill on a motorway, after the engine has fully heated up. Drop down a gear and floor it up the hill. You should see black smoke in your rear view mirror. Repeat on the next hill - hopefully there will be less or no black smoke. Afterwards, the engine should feel more lively, and the MPG will improve on the next tank.
 
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KekseKaempfer

A2OC Donor
Filled up again today after my somewhat lax driving style and got 62.2. Back to normal, easy going from now on. See if I can get past 70mpg.
 

KekseKaempfer

A2OC Donor
.




* If it is coked up, find a long hill on a motorway, after the engine has fully heated up. Drop down a gear and floor it up the hill. You should see black smoke in your rear view mirror. Repeat on the next hill - hopefully there will be less or no black smoke. Afterwards, the engine should feel more lively, and the MPG will improve on the next tank.
I do give it the beans on the up ramp from Newbury onto the M4 every so often. Early days, you could see the smoke whenever you accelerated, now I rarely see any in the rear view mirror. I haven't used my second bottle of Redex either, these last two tanks have been Redex free.
 

Cloth Ears

A2OC Donor
I don't drive with economy in mind, although I do try to minimise my use of the brakes by reading the road and anticipation. On the motorway, I prefer to cruise at 'outside lane' speeds, and my 26 mile daily commute is a mix of 60/40 motorway and queueing traffic. I enjoy the lively performance available from my tdi90.

I get around 50-52 mpg and always have done, in the 10 years I've owned the car. The climate control seems to lose me around 1-2 mpg, which is, I think, a fair compromise for a dry and condensation free interior even in the cold and wet months we get in Manchester.

I have been told that high torque at low engine speeds is the way to kill the DMF, so I don't use the highest gear at lowest speed technique, and I do find the car feels happier used between 2000-3000 rpm if you are using the performance available.

So, an interesting comparison between 'real world' figures using the car's capabilities, and driving with serious economy in mind.

Just as a matter of interest, I once drove from Manchester to Biggin Hill airport in Kent, and back again in a day. According to the trip computer, my average speed for the entire trip was 79mph, and average fuel economy 49.9 mpg. For a c500 mile day trip, I thought that was pretty respectable.
 
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