U guyz wont believe but the max i have got is 290 km on Alto 2008 with 55 kg cylinder on 220psi pressure (Rawalpindi to Lahore) but before that i had my carburetor cleaned, fuel jet valve , plugs, air filter, oil and oil filter replaced and yeah tuning as well. I dont go more then 85 on GT road,and on top of that some hyper mileing skills
( Let the other cars clear the way for you, leave accelerator if you see a truck on a distance of 200 to 300 meters rather then continuing on high speed and then braking just behind the other Vehicle)
before this tuning i was getting up to 160 on cng and 7-8kmpl on petrol but now even on petrol i m getting 15+.