Just recently I drove a Passo (Specs are, 1000 CC (precisely 996 CC), 3 cylinder 12 value, DOHC (double overhead camshafts, twin cam), Model DBA-KGC35-AHEDK, 1KR FE Engine, Hanna Plus, 165 / 70 R14 Tyres, start slot, CVT, ABS, 2 x air bags). I did not change any thing in the car no plug, starter, battery, coolent, any thing and decided to drove it in city (DHA Islamabad to F-11, my usuall ride) and on motor ways from Islamabad to Peshawar and Islamabad to Hassanabdal and to Abbottabad and back off course.
I used 26 psi on front tyres and 30 in the rare one. Used PSO Premier XL petrol for my rides. I am kinda take care driver, where I do not push too much on accelerator, My maximum speed usually remain with in road priscribed limits.
My experience shows following results with above vehicle.
In city with AC = 14 Km/L
In city with out AC = 16.3 Km/L
On Highway with AC = 16 Km/L
On Highway with out AC 19 Km/L.
These are the averages and over all readings I calculated to the best of my knowledge, Odometer at times were showing 21 Km/L as well.
Ride was comfortable, other than Body kits on Hasanabdal to Haripur were kissing on bumps.
other than the above calculated superb millage, I wont consider installing CNG on Passo for below reasons as well.
CNG time is over, LPG is around corner.
Non availabilty,
Risk Involved with safety
Reduction of boot space in vehicle.
I hope this clarifies.
Faiz