What is Involved in Converting a Stock Vehicle to CNG?

Not much really. A place to put the tank, plumbing and a bonnet. Of course a tune-up would be necessary (timing, carb/injection setup, etc). If doing a true DIY (not buying a kit) you can do it for next to nothing. Stories abound about people scavenging the tank, which is generally the most expensive part, from older CNG vehicles that were at end of life, but the tanks were engineered to last 25 years or longer.

Here, in Argentina almost a 20% of cars are dual (CNG / gasoline), all over the country you can find CNG stations at 100 miles intervals. This is because the range of a car on gas is of about 120 to 150 miles. There are 5 or 6 car manufacturers here, and some have been selling dual cars for more than a decade. Conversion is quite easy, but it only can be done at licensed selling points. Conversion costs from 2 K to 3 k depending on the size of tanks you buy, and is usually done in 4 to 6 hours. A safety inspection is mandatory every 2 years, and as cars get older, once a year. A counterfeit-proof sticker is placed at the upper-right corner of the windshield with the licence plate # of the car and expiry date of the safety inspection on it. If you have no valid sticker you get no gas. Over the time, CNG has proved to be much safer than gasoline in most road accidents.

Would older, less complex, vehicles be easier to convert?

Yes and no. The computer interface could be eliminated but a 12:1 compression ratio is needed and then the cost for the tanks would remain the same.

You'd realize a savings of about $400-$500 but you'd save much more using wood gas instead though you'd then be traveling in an ancient vehicle too.

Do you know what ignition points are and the maintenance required on those older less complex vehicles? They were much larger inside too allowing for increased velocity of the body (yours) before smashing into the interior in a collision.

You need to think this through a bit......maybe you already have and in that case with few tools and desire you can do it youself and save $3000-$4000

Shaving the cylinder heads and probably the intake manifold too will presto the 12:1 compression ratio unless replacing pistons also. And the older cast iron valves need be replaced with harder sodium filled types then the valve seats need be replaced to handle greater heat too. Other than that and fashioning a regulator you're well on the way already.

But 12:1 compression though optimal for CNG can be problematic depending on the octane of gasoline available.

Sorry, I have to be negative on this subject as gas has a lot of problems if the car/engine was not designed from the drawing board for gas.

Simply don't do it on your own car.

1) Gas burns far hotter than petrol, then its not allowed to tow anything when running on gas due to possible overheating problems. In all "good" conversions this is printed in large letters on the first page of the instruction manual. You must up rate the cooling system and probably add an oil cooler, but the engine will still not last as long as it would using petrol.

2) If you have ever seen inside a turbo diesel engine, you will see the extra oil jets used to cool the piston from below, you need to add these to the motor, plus an uprated oil pump to supply the extra oil at the correct pressure to everything. The use of fully synthetic oil can help in protecting the motor further.

3) Gas "lubricates" the valves even less than lead free petrol does, the valves must be able to handle the heat better.

Naturally, some companies have (Ford for example) properly designed engines able to run on Gas, but its really not as a simple thing to do as many believe, many companies here have gone to the wall due to the guarantee problems.......

Either get a properly designed system installed by a reputable company, who have been doing it for at least a couple of years, installed with a full guarantee, or leave it well alone. In Germany, a normal guarantee is at least two years, less is illegal here.....

With gas you will get at least 6 months relatively problem free......hopefully.......

Sorry to be so negative, but I do wish you well in the case where you decide to do it anyway.....

By the way, there are some really good diesel engine conversions around that really do work well on gas with diesel, if I was going to do it, that would be the way I personally would go......due to the fact that diesel engines are usually built with far more reserves in terms of stability and long life assuming the maintenance is performed correctly....Mainly the conversion is made on larger diesels for buses etc..

PS. Do let us know how you get on with the conversion, assuming that I have not put you off completely.....

Sorry to disagree, in my country CNG has been used for the las 30 years and are about 1 million cars running on gas. All alleged "disadvantages" turned to be a myth. Many of them are taxis, having reached 500K Km with no problems at all. Oil lasts longer and there are by far less emissions. Some HP get lost, but -in general, this is not a big deal. The key is to have a good quality CNG equipment, and to have it checked every 10k Km. That´s all.

I don't have the stats handy (on the 'net somewhere, I am sure) but the US has also been using CNG in government fleets for years. This includes our buses for urban/interurban transportation.

I know personally that the cities of Norfolk, Virginia Beach and Chesapeake in Virgina have city vehicles including regular work trucks, sedans, 5 and 10 yard dump trucks, etc. which are powered by CNG. They all have vehicle logos and are very proud of the fact that they are using this "new" technology.

Of course, they were not necessarily converted, but were mfd that way from the get-go. It just goes to show that it can be done in light vehicles and heavy equipment.

Let me tell you about the CNG trucks that the City of Houston purchased. Not a single one of them has been reliable. They spend well over 70% of their time in the shop for repairs and have cost the city a small fortune in both initial purchase price as well as maintenance costs. factor in the refueling system infrastructure costs and it has been a complete and utter disaster.

In your country, many cars are built to use gas by the manufacturer. That is the significant difference. The conversion companies have a lot of experience.

I mentioned this in my post.

I am personally against conversions, especially as a DIY project.

You should try reading my post with far more care....

The trick is simple, the engine retains its diesel tank and injection system to act as an igniter to the extra injected gas.

In cheap systems the gas is added in the inlet manifold, but this reduces the amount of air.

A better system either adds an extra injector in the head or modifies the diesel injector to allow both fuels to be added.

Either way the diesel/gas engine is cleaner and quieter, as well as more economical!

Basically the amount of diesel used per firing stroke is the amount needed for tick-over.....

(Note. For gas read CNG or similar, not petrol!!)

Here you may find more info about Conversion equipment in Argentina:

http://www.galileoar.com/en/index.php

please let me know your thoughts

Cosme

Not needed, thanks.

Tell the OP yourself.

Hi Andy, sorry to disagree again, in my country very few models are built to use gas or dual. The rest of them is intended to use either gasoline or diesel. DIY conversions are absolutely illegal down here. The quality of the conversion equipment and conversion companies is out of question as they do not void the warranty VW, Ford, Chevrolet, Toyota, Citroën, etc give when you purchase a new car.

It's too bad that DIY is illegal in your country.

I would never do this to a new car...only something older I wanted to tinker with. No tinkering in Argentina, eh?

We love tinkering... but only the DIY stuff that can blow your entire neighborhood into the air is forbidden down here! To have 200 Bar of CNG in a tank is no joke!

My reading tells me that CNG is safer than gasoline in vehicles. But I'm sure that means properly designed ones with appropriate tanks.

check this site for info about gas equipment: http://www.galileoar.com/en/index.php

yeah, that would be frowned upon here too.

In some countries, DIY is king. Not good in this area.

Your country is fully correct in banning such things.

Your country probably has the most experience in this sector, the rest are just playing "catch-up"......which is EXACTLY why I tried to persuade the OP NOT to attempt anything himself......

Now do you understand what I was trying to say?

(Please re-read all my posts if you are still unsure!)

Ja, hab´s kapiert! (Yes I did)

Es ist gut so!

Assuming something does not make it true.

What you wrote here:-

DIY is king in America...we just don't need the over-regulation you seem to embrace.

is simply neither correct, nor is it factual......I embrace nothing like that.....Why? Because am happy with the "balance" of what is allowed and not allowed here......and I do not bitch about it either. I can leave if I wish. I simply don't wish to!!

I never even said, nor do I know, if Germany allows vehicles, DIY modded with gas on the road, probably only after exhaustive (expensive?) testing and checking.....exactly how it should.

Go and bitch over something worth bitching about is my motto......not something like this......

I have no problems with idiots sending themselves to Kingdom come with DIY experiments, but its the innocent ones that they often take with them that I don't agree with......

I trust that I have set the record straight.

Of course you are saving the environment at all of that expense. According to the US Department of Energy greenhouse gas emissions drop 21%-26% (averaging in the methane increase) with a 100% drop in petroleum usage for CNG.

Better mileage, more power, similar maintenace costs, less worrisome emissions, etc.

What are the drawbacks here (except for the tank/storage/filling)?

I have a 1999 1500 Dodge Ram Van with a 318 engine. It has 99,000 miles. I will be checking around for someone with the experience needed. I would not attempt it myself. I am lucky to get 15 mpg on the road. Thanks for your information. I would also have to find a service station locally or an appropriate compressor etc.

CNG is selling for 78 cents in Oklahoma. About $1.20 in Utah. About $2.80 in California and Chicago.

cngprices.com provides a great map for Europe and USA. Prices are updated.

cngsolutions.net/specials in Utah states that it will do a bifuel conversion to your vehicle, that will cost your $49 per month. That sounds way to good to be true, I admit.

They also sell approved CNG tanks in all sizes for good prices.

Here is a handy free mini manual on conversions.http://www.younkincng.com/