Following are my vitz 2003 model fuel averages with complete details of any maintenance done between fuel average calculations:
All fuel averages are with zic oil (10w40) and all averages are taken in city driving (Where distance covered is on long , I have explicitly mentioned it). Daily distance is 41 kms with 12 speed breakers and 14 times i have to pass through traffic signal daily.
Sep 2014: 350km in 33 litres, 10.6 km/l ( with 90% ac and fuel from total petrol pump. Normal fuel no high octane).
Oct 2014: 381km in 36 litres, 10.58 km/l (with 100% ac and fuel from total petrol pump. Normal fuel no high octane)
Maintenance: Plugs changed to original from toyota walton motors, tyre changed from bridgestone b250 185/70/13 to dunlop sp sports lm703 175/70/13.
Oct-Nov 2014: 425 km in 36 litres, 11.80km/l (with 50% distance with ac and fuel (no high octane) from total petrol pump)
The distance also includes 40km travelled on lahore ring road.
Maintenance: Wheel balancing and alignment done from toyota walton motors (2000 for both). I dont go to toyota waltons for anything apart from wheel balancing and alignment :-).
Though I am not big fan of PSO, but now have filled fuel tank with it and will update you guys with pso mileage in next 6-7 days. After that i will try mix of high octane as well that will improve mileage further.
My observation about tyre size change is that changing height wouldn't affect fuel mileage much, but changing tyre width will definately effect it. So if you car gives 12km/l with 155/*/* to 175/*/* then your fuel average will drop by 1 km for each litre i.e after size increase you will get 11km/l.
Nov 2014: 432 km in 38 litres, 11.36km/l (with 35% distance with ac and fuel from PSO cavalary ground petrol pump)
The car remained on standing position with start for 25 minutes, to compensate that i added 3 litre extra high octane (count included in 38 litres). So clearly PSO average is not as good as Total.
Nov 2014: 397 in 34 litres: 11.67 km/l. petrol from total pump.
Nov 2014: 565 in 48 litres. 11.77 km/l. Petrol from PSO cavalary ground and this 48 litre also includes 12 litre high octane. (I have real doubt in Cavalary Ground PSO Hi-Octane Fuel)
Dec 2014: 403 in 32 litres. 12.59 km/l. Petrol from PSO cavalary ground(120 km highway distance and 50 km with fulltime ac).
Now I have got my tank again full from total zoom MM alam road, let see their readings. They have better petrol and secondly mostly girls operate there so no hangy phangy while filling tank. Because of good quality petrol i go there although they charge me 2% on credit card.
Dec 2014: 433 in 37 litres i.e. 11.70 km/l (Petrol from zoom mm alam road)
Dec 2014: 592 in 48 litres (12.33 km/l). This includes 14 litres hobc and one STP FUEL INJECTOR CLEANER(400 ml). All distance in city i.e. mostly in lahore cantt.
Jan 2015: 393 in 33 litres: 11.93 km/l. Petrol from PSO cavalary ground. All distance mostly within lahore cantt.
Feb 2015: 416 in 34 litres: 12.23 km/l. Petrol from PSO cavalary ground. All distance mostly within lahore cantt. 14 litre of HOBC
Feb 2015: 458 in 35 litres: 13.08 km/l. Petrol from PSO cavalary ground. All distance mostly within lahore cantt. Tank fuel of HOBC i.e. no normal petrol
Fuel Average on Highway
I recently calculated fuel average on Long route. The total long route journey was 214 kms (36 km in traffic of Lahore i.e mall road while leaving and return and rest on long) for 3 bars drop. Fuel was 20/80 Hobc/Normal. Mobiloil changed 3 months back to fully synthetic zic 5W40. So, per bar 70km, full tank of 38 litres ( I am 100% sure my car's fuel tank is 38 litre) would have done 70X (8 bars)=560
560/38= 14.73 km/l
(All journey without ac)