My Cultus EFI used to give me 225+Kms per cylender, now you can compare if the mileage of belta is good or not...
Now i have belta and it gives me 16-17Kms/litre, so as compared to 160Kms/cylender, i don't think it is wise to convert it on cng....
125 Km on petrol = about 650 Rs, and a cylender cannot be filled in less than 700Rs, so why to waste a big amount on cng kit and ruin the car and still get low mileage ....