What MB would be a good conversion to CNG? I would think later cars with the computers and such might cause issues, but too old a car would not work well either. I have a CIS car (6.9) but I am not sure if it is a good candidate, the CIS stuff needs to be rmoved, I don't think you could run dual fuel.

Thoughts/ideas?


thanks
Fred

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It takes a big heavy tank to hold CNG. Pressure is considerable and mileage is very limited for any tank you could put in an car. Around here, some Public Service vehicles are running CNG and I think they get about 60 miles on a big tank in the pickup box. I believe one car manufacturer has a prototype CNG vehicle with a number of smaller tube type tanks mounted under the car, but still short trips only because you are out of fuel.

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Junqueyardjim
Christianity, if false, is of no importance, and if true, of infinite importance. The only thing it cannot be is moderately important. C.S. Lewis



1983 Mercedes W123 240D 4 Speed 285,000 on the road with a 617 turbo, beautiful butter yellow, license plate # 83 240D INDIANA

2003 Jaguar Type X, AWD. beautiful, good mileage,
Mom's car, but I won't let her drive it!

I had a 3.5 W108 converted to LPG back in Europe some years ago and it worked very well. Here in the US 4.5 with Djet injection would be good cadidates with easy conversion to dual fuel. But CNG is no LPG...

Fred

I spoke to a fellow some time ago (when gas was more then $4) who converted his truck to run propane. He replaced the truck tank with tank that can hold propane and said he was able to fill his truck at 40 cent / gallon.

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With best regards

Al

I believe Honda is the only one making CNG cars at this time(Civic CNG)
Ford and GM have made them in the past.Most of them were sold as "fleet" vehicles,and used by government agencies.You occasionally see them for sale/auction.They do need big tanks to have much range.As city/county cars rarely venture far from a fueling station,this was less an issue for them than it might be for you or I.
Here in CA,our main utility company(Pacific gas and electric)sell a fueling station adapter that is hooked up to your homes gas meter.You can also fill up at a number of fueling stations run by PG&E.There are no road taxes taken out of CNG,so one must register and pay quarterly taxes bases on the number of gallons purchased.I believe it currently works out to about 1.50-1.75$/gal with taxes factored in.
As far as duel fuel,I've only seen this done with propane.It was always on a carb,not injected vehicle!
The propane was injected into the incoming airstream and mixed in the carb just like gasoline.I'm not sure how this would be done on an injected car.Ford and GM both make injected vehicles that run on E-85,but it is a liquid,not gas fuel.
I do know that due to the cleaner burning fuel,engine life was increased substantially.I've seen oil drained out of a propane powered police car that was as clean after 7-8K miles as it was when new.
I'm not sure about CNG,but propane has less BTU's than gasoline,so fuel mileage decreases by 15-20%.
FWIW,the CNG civic costs several thousand dollars more than its gasoline cousin.Here in CA there are govt incentives/rebates that cover most of this difference.
I think personally this is a more viable "green" solution than the silly hybrids with expensive batteries that are very toxic to make and dispose of.

The CNG tank issue can be worked out. There are composite tanks available that are much lighter than the steel or aluminum tanks. Below is a link to a CNG dual fuel article. Around here it's impossible to find CNG that is available for public use.

http://naturalgasconversionkits.200326.free-press-release.com/

As far as propane is concerned, it's more widely available. Around here it's subsidized as a motor fuel so it costs about 1/2 as much per gallon as getting a BBQ tank filled. There are some slick EFI propane systems out there.

When all is said and done don't expect operating costs to be lower.

LPG set up in my W108 3.5 consisted of a big additional tank in the trunk behind the rear sit. Filling was next to the fuel filler, both hidden behind the tag plate (wider in Europe than in the US). Gas was sprayed through a venturi fitted on top of the throttle body. I was starting with fuel and was then shifting to LPG after 10 seconds by simply pushing on a switch. This would cut the fuel pump as well as the injectors and open the LPG supply. Shifting from one to the other was hardly noticeable and I could do it in any traffic condition. Engine was more torquey with LPG, but had 15-20% less power at higher rev. So when I needed power to pass I was just switching back to fuel and back to LPG while cruising. Consumption was 20% more with LPG, but cost was reduced by 50% to cover a given distance.

Home compressors are available and the Fed has tax credits that can cover the cost (CNG), but it takes overnight to fill it. CNG and LPG have a lower volumetric efficiency than gasoline. CNG has an effective octane of about 130, so putting on a turbo is a great way to get power back.

The main trouble with injected systems is the systems themselves are old and don't work like they should so a conversion might not work so well either.

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MB-less