The Stovebolt Site Forums The Shop Area Engine Shop Compressed Natural; Gas (CNG)

I'm seriously considering converting my '68 truck to CNG. I was watching a piece on the local news tonight about people running CNG where the fill-up is less than TEN dollars, and the range is very similar to what a gas-engined vehicle gets. I'm NOT talikng propane, which is also a good alternative but costlier than CNG. There are several CNG filling stations in the OKC Metro area, too!

Anyone have real-world experience with CNG???

Hy patrick66, fuel tanks for CNG must be extremely strong, hence heavy, and to retrofit enough of them to get near the range of your standard fuel tank would be tricky and expensive. You are very limited on where you can install the tanks, other than in the box, then you can't use the box. Make an informed decision, hope that helps.

Government vehicles are using them in Texas. I haven't heard anything good yet. On one hand, the government is notorious for spending $100 to save $1, and on the other hand mechanics are notorious for complaining about anything new.

One of my cutomers is a gas company and they run thier fleet on CNG. Everything from cars to heavy duty line trucks and they do it w/o problems or concern. They also do (or did) offer it to the public as well. There heavy duty trucks are on a 12 year replacement cycle, maybe longer now.

If you raise the compression of your engine and develop a fuel injection system to run it (Bosch makes CNG rated fuel injectors), then it can be economical. Most stories I've read are that trying to do dual fuel with a converted propane carb result in poor performance and bad economy.

Honda makes a CNG civic. Afaik that's the only CNG vehicle you can buy new in the US right now.

I talked to a guy that works for the gas company here as he was filling his company truck at the pump and ask him why they weren't running on CNG. He told me that the new Chevrolet's like he was driving were not available with a conversion to run CNG, but that the company was still running alot of the older trucks on CNG and he said it cost like $1.00 per gallon to fill with CNG. He also said they are a great and economical system when they work, but if you ever have to have one worked on it can be quite expensive.

A CNG conversion for your truck is straightforward and will be similar in many ways to a propane conversion, just more expensive. You will need a CNG cylinder rather than a propane tank and a pressure regulator instead of a converter. CNG also has a significant power loss compared to gasoline but this shouldn't cause you to have any problems keeping up with traffic.

Because CNG is stored as a high pressure gas rather than as a liquid (in the case of propane), the cylinder won't be able to hold as much fuel. A cylinder only holds the equivalent of a few gallons of gasoline so you will either need to refuel more often or install more cylinders. The more you drive, the faster the payback.

I heard your range with CNG is only 40 miles. Hardly seems worth it if that is so. I guess you could get a tank that took up the entire bed!