1) There are many brands of cylinders available in market. OGRA (Oil and Gas Regulatory Authority) of Pakistan has list of approved CNG cylinders at http://www.ogra.org.pk/images/data/downloads/1275560046.pdf. Among these cylinders, all Italian cylinders are considered better than others. But I could not find any new Italian cylinder in the market. Faber, which is regarded as best, comes with all company fitted CNG Suzuki cars. It is also light in weight than all other cylinders.
2) I read at http://tribune.com.pk/story/239492/ogra-bans-cng-cylinder-import-from-12-suppliers/ that OGRA has banned import of Faber and EKC cylinders. I sent a query at Pakwheels to know about ban on
EKC as almost all CNG workshops are selling it.
Here is link to my post http://www.pakwheels.com/forums/cng/176639-ekc-dubai-banned-ogra. I also tried calling OGRA representatives but could not find any information from them. I even called at their Islamabad office and sent an email to their chairman and his team but none of them bothered to reply.
3) Finally, I got below reply from OGRA regarding the email I sent to all their officials.
4) The capacity of CNG cylinder is measured in water liters. Cylinder installed my car was Delamine (Italian brand) with capacity of 28.5L. Its CNG capacity was 4.5kg CNG. I planned to change it with 50L cylinder that can contain 8kg CNG.
5) I tested my car's cylinder from HDIP Lahore and put an add to sell it on back of my car. I also placed an add on OLX which I think is a very good place to sell your stuff. But I did not have much time so I decided to sell it to some dealer.
6) I got list of CNG centers in Lahore from http://www.pakcng.com/CNGdealers.asp?City=Lahore. I called them one by one but all of them asked me to visit their shop. So I decided to visit Bhawalpur road (road of Miani grave yard).
7) I also visited this workshop as it was recommended by a pak wheeler http://www.pakwheels.com/forums/cng/173518-best-workshop-cng-lahore-johar-town. I got the best rate from Bahawalpur road dealers. My plan was to go to Noor CNG a.k.a Butt CNG but he refused to purchase second hand cylinder. So I went to Gasline, had some negotiations with him and finally purchased new 50L E.K.C in 9k with exchange of my current cylinder.