Anyone converted a 911 to CNG, propane, LPG?

[Poohsan]

Anyone converted a 911 to CNG, propane, LPG?

This question was asked before but no answer was provided. I've seen many cars and trucks which have had a piggyback system installed so that the driver could switch back and forth between gas and CNG. Has any one here tried this on a 911?


Anyone converted a 911 to propane/CNG?

[Mr.Puff]

:P No, but in this months excellence there is a 210hp alternative fuel 987.

[stevemfr]

You have to have a dual fuel system w/LPG as it's nigh on (economically) impossible to get a normal gasoline engine to cold start on LPG. Sure it can be done - but is it really such a good idea? Technically it is a non-issue. Costs in building/certifying/etc. are certainly going to be a factor for a 911. +, all other forms of fuel can be expected to rise dramatically in price as the demand increases (if you're thinking about doing this on a Porsche - imagine what all the owners of cars that have commercially available, proven systems to choose from are thinking!)

And, as an aside, I've been reluctant to do a conversion on my Range Rover due to the loss of luggage space - and there is quite a bit of luggage space in contrast to a 911. And the weight of the tank alone...

I had to chuckle at the comment in the other thread: curiosity killed the cat... for a good reason!

[gestalt1]

i briefly looked into propane. when i was a kid an older relative owned a propane distribution business, he had his pickup truck converted. it had a tank the size of a truck bed tool box. i think it works by letting the liquid propane return to a gas state at the carb, the carb is acting as a throttle body. propane has less energy content so the mpg was lower. i saw a chart on an alternative fuel web site and because of the greater volume of slightly cheaper propane required the cost ended up being the same as normal gas per mile. i think it could be added to a 911 with carbs, i was trying to find if the injector system could be interfaced with the mfi injectors so you could switch between the carbs and the propane mfi system. my thought was to use propane for the drive to and from the track and use the carbs at the track. i think it ends up being a lot of cost and engineering for very little savings.

in my brief research it looks like making your own biodiesel (diesel engine required) or cng are the only clean burn money saving options. (or just plain drive less!) To me hybreds are an overly complex system that are going to have far worse environmental impact than gas cars do - when the battery pack needs replacement.

[gestalt1]

i just thought of something else related to propane. in the eighties Morgan cars imported all (however many that is) of there cars as propane to avoid having to get them emissions certified. if they could fit the hardware to run a morgan on propane i would think a 911 sized systme would be possible.

[RWebb]

high wt. and low energy value of other fuels make such conversions problematic for sports cars

[rusnak]

It's possible to modify carburetors to run on propane. I know we've done it on the farm to more than half of our trucks. The reason at the time was that propane was much cheaper.

I don't know if it could be done on a 911, to answer the question. But I think it could be theoretically possible.

But as Randy pointed out, no one in their right mind would EVER do it! You can't store propane in a regular gas tank. You'd need a HUGE pressure tank that would be extremely heavy to store the propane at high pressure in it's liquid state. The pressure tank would be maybe upwards of 150 lbs dry, and more than twice that filled. You get good mileage on propane, but you have to because it's not as readily availble as gas.

The other thing is you don't get more power on propane vs gas, and some of it always leaks out. So you have a stinky, heavy "sports car" with a huge tank strapped on it somewhere, most likely on top because you can't have the inlet or vent valve in an enclosed area.

[Brian 162]

My old work truck (5 ton) ran on natural gas and gasoline. In the city it ran o/k but there was noticeable power loss on the highway.
The price of natural gas is around 80 cents a litre (compared to $1.30 per litre and climbing).
The pressure of the tanks when full is 3000 pounds.
I'm not sure you would like a 3000 pound bomb in the trunk of your 911.

[bhyde]

We experimented with CNG a few year ago. Let's just say, well, mistakes were made...

[HarryD]

Originally Posted by bhyde

We experimented with CNG a few year ago. Let's just say, well, mistakes were made...

My Base fire Chief shared this presentation with me a while back.


Uploaded on authorSTREAM by Christo

Gives me the willies.....

[Milu]

LPG and methane conversions are common in Italy. One of my clients is a distributor and installer of the equipment. He says technically a 911 would not be a problem. The biggest difficulty is lack of space for tanks. Apparently a couple of 911s have been done.

[creaturecat]

My 1967 GMC pickup truck - 6 cyl - converted in 1981 - never a problem - saved me 10's of thousands in fuel costs. Probably changed the spark plugs twice in 27 years. Started well at -25 degrees F - when I lived in the Midwest.
Present cost .79/L (3.20 per US gallon) versus 1.36/L (5.40 per US gallon) reg gas. When I converted the cost of Propane was 4 cents per litre (.16 per US gallon) !
BTW - premium for the Porsche is now more than 6.00 per US gallon here in Canada.

[Porsche_monkey]

I think only LPG is practical. The L is for liquid, natural gas can not be pressurized enough to get it liquid, so you won't have the range you likely want.

I guess you could steal the stuff you need from an old forklift truck.

[Poohsan]

I'm still looking into this. If one goes the CGN route you can install a compressor / pump at home to fuel your vehicle. There is also a tank available that fits in the space for your spare. The above noted safety defiantly put a downer on the whole thing. I've seen piggy-back systems in other cars that worked quite well. I found a few links to companies that provided systems that can be added to a gasoline engine.

http://mycngkit.com/Buy_CNG_Natural_Gas_Bi-Fuel_Conversion_Kit_For_Any_Ford_CNG,_Chevy_CNG,_G M_CNG,_Nissan_CNG,_Toyota_CNG.html
http://www.transecoenergy.com/pages/CNG_Conversions.htm

http://www.omnitekcorp.com/altfuel.htm

[rusnak]

ok keep us updated of your work. Post lots of pics. We like movies too, especially the first time you start it up.

[HarryD]

Originally Posted by Poohsan

I'm still looking into this. If one goes the CGN route you can install a compressor / pump at home to fuel your vehicle. There is also a tank available that fits in the space for your spare. The above noted safety defiantly put a downer on the whole thing. I've seen piggy-back systems in other cars that worked quite well. I found a few links to companies that provided systems that can be added to a gasoline engine.

http://mycngkit.com/Buy_CNG_Natural_Gas_Bi-Fuel_Conversion_Kit_For_Any_Ford_CNG,_Chevy_CNG,_G M_CNG,_Nissan_CNG,_Toyota_CNG.html

From this web site:

"Can the natural gas tank explode during accidents, or when the car heats up?

Generally speaking, a CNG natural gas tank is much more secure than a conventional Gasoline tank. Gasoline tanks are usually made of plastic, which is much less secure than a robust natural gas cylinder of Carbon Fiber. And even though the Gasoline tank is made of plastic, only very few cars burn after an accident. Further, once the pressure of the line from the natural gas cylinder to the engine exceeds a certain pressure, the valve at the cylinder will automatically shut. This way, maximum security is guaranteed, and no natural gas is able to evaporate. Even police cars drive on CNG in certain areas of the country."

A carbon fiber tank is what ruptured in the slide show I posted above.

http://www.transecoenergy.com/pages/CNG_Conversions.htm

"How is cng fuel stored? CNG is stored on board vehicles in high-pressure (3,000-3,600 pounds per square inch) in tube-shaped cylinders that are attached to the rear, top or undercarriage of the vehicle. The cylinders meet very rigorous safety standards. They are made of high-strength materials designed to withstand impact, puncture and, in the case of fire, their pressure relief devices (PRDs) provide a controlled venting of the gas rather than letting the pressure build up in the tank."

OK, what are the tanks made of? If Steel they are very heavy. If Carbon Fiber, then see above.

http://www.omnitekcorp.com/altfuel.htm

These guys do not offer the tank. why? Liability maybe?

Folks, CNG/LPG is not a bad fuel, but safe management of ANY fuel is critical.

We need more than glib statements by the marketing departments. If they want to sell me (and I hope you), then we should see a detailed report, stamped by a Professional Engineer, stating how and why the system is safe and what is required of the end user to ensure it's ongoing safety. Otherwise, I would feel very uneasy being near a car that runs on this stuff.

[kenikh]

Just buy a kit; these are easily installed on a car with a common plenum and single TB like a 3.2:

http://www.mycngkit.com/

edit - woops, should have read further