Hello
I've been monitoring my fuel consumption with a paid version of the well known Android mobile app of "Torque". I've set it to enhance itself for fuel consumption monitoring. I've been tweaking this one multiplying factor to fine tune the app to be spot on for my vehicle.
Some weeks back I had done over 1400km (i.e. about 900 miles) of mixed driving, filled the tank and compared the results to my Android app. They both showed me 4,3 Liters/100km. Good. I finally had the factor dialled in after 5 months of tweaking.
Enclosed is my personal best over a distance of 42,6km/26,47ml. Result is 3,1 litr/100km, i.e. 90,6 MPG. This reading does not contain any accelerations from the traffic lights, nor gunning down motorway on-ramp. I started logging the fuel consumption as I was driving, warm engine, all systems stable. Absolutely no overtaking, I drove just to keep up with the traffic at about 80km/h speed (i.e. 50mph).
Even one simple stop n go traffic light will bring down the mpg figure quite considerably.
I can have 70-72MPG on motorway, with varying speeds of 53 to 62 mph at somewhat 50/50 ratio, preferably no overtaking.
Audi A2 with 75hp 1.4TDI looses good fuel consumption at higher speeds. I have logged 120km/h (74,5mph) speed repeatedly to consume 5,6 litr/100km, 50,5 MPG. Looks to me that A2 fuel consumption at these speeds is more or less the same as 1.9 and 2.0 liter diesel family cars, which is quite surprising.
All numbers above are a solo effort. No drafting after lorries or big trucks.
I expect to shave off another 10% from these figures as I get my eprom reprogrammed.
In case anyone is keen to know what shoes I have, I have 165/65-15 inflated to about 3,2-3,4 bar. Close to 4.0 bar inflation the tyre will roll better, but it will also transmit road imperfections to cabin, which I do not like. My tyres are spikeless winter tyres (so called friction tyres here in the northen Scandinavian countries). I guess some percentage of MPG will improve as I get to have better rolling summer tyres. To gain longer gearing, I need larger circumfence. 165/80-15 seems like a good tyre for that.
More later.
-A