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Would you be interested in cng on your truck?

  • Not a chance

    Votes: 11 23.4%
  • Yes, if I could add as much or more power than I can with propane

    Votes: 11 23.4%
  • Yes, if I could lower my cost per mile

    Votes: 23 48.9%
  • Yes, if there is a fuel station near me

    Votes: 3 6.4%
  • Only because I have access to free gas

    Votes: 2 4.3%
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Discussion Starter · #1 ·
I am trying to find out if there is any interest in a supplemental kit to put cng on trucks. A guy in the cng business told me that the price of cng is dropping fast and will soon be a good value. It will be more detonation resistant than propane, so it should make great power.
 

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Marc,

I don't know anything about CNG, so I cannot vote intelligently in your poll. I do know that the diesel work truck we had converted to a full CNG setup (14-ton truck for electrical distribution service) was loud and gutless, so we got rid of it. If the install is sanitary and offers better mileage and/or more power then tell me more! Also, would it be possible to install a pump/compressor in my house to fuel a tank from my residential natural gas line?

Thanx!
 

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Discussion Starter · #3 ·
Mountainstoner,
I am going to assume that the work truck you are referring to was converted by replacing the diesel engine with a gasoline engine that was converted to cng. If so, it may have had stock gasoline compression. This would yield poor power. CNG likes compression around 13:1 on a spark plug engine. On a diesel, it is an entirely different animal. I am getting ready to put a system together and test it. FuelMaker of Canada makes residential compressors. I'll find out how much they are going for these days and post it. I have a gas well so my fuel cost would be the cost of the compressor and the electric to run it. Another consideration is that the compressors used to require rebuilding every 4000 hrs, and it was $400. So, you have to add that into the mix.
 

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isn't CNG stored at higer pressure requiring $ DOT tanks. CAT used to sell spacers to raise head to lower compression and replace prechamber with sparkplug adapter and install mag in place of inj. pump. like to know how it works out though.
 

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3000-3600PSI
Marc knows I'm interested.

We are in process of getting wells drilled right now.

May end up w/ a couple of tanks and swap them for filling since the small pump takes a while to fill the tanks.
 

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Discussion Starter · #6 ·
Tim,
Do you mean swap tanks by removing the empty and installing the full one? CNG tanks are HEAVY. It won't be like a forklift tank. Another thing to consider is the difference in the size of the tank for the amount of fuel you have. Since it isn't liquified, the tank is approximately 3 or 4 times the size of a liquid tank to have the same range. For example, a 20 gal cng tank is the size of an 80 gal lp tank. When you buy cng, the pump reads in gallons. But you aren't buying gallons, you're buying lbs. The pump actually weighs the fuel and gives you 5.66 lbs of fuel and calls it a gallon. This is done instead of cubic feet because cng varies alot in btu/cu ft from one place to another. Some gas is only 750 btu/cu ft, while other is as much as 1300. The weight of the fuel is the only way to measure it and keep it fair. So, a gallon of cng will go farther than a gal of lp because lp is only 4.25 lbs/gal.

Regarding the diesels that are converted to cng only, it seems like you would be giving up alot of efficiency. I think the supplemental idea will be the best of both worlds. You can use alot of cng if it is cheap, but can run all #2 if the need arises.

The compressor is still the hurdle. I know a dealer who has a few used FuelMakers, he wants $3500. New ones are at least $5500, and they only compress a gallon an hour. So the truck is going to be hooked up to the compressor alot of the time.
 

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I'd do the mix w/ #2.

I thought about smaller tanks and have 2 of them so one is filling while other is being used, but tank weight may hurt that.

Any links to tank sellers so I can get an idea of what is available?
 

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Discussion Starter · #8 ·
I'll get in touch w/the guy here in town that does gasoline to cng conversions and see what is available. He has quite a supply of used tanks, but I'm sure he can get anything new also since he is a dealer. My guess is that new tanks will be mighty expensive.
 

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Have seen a gm truck w/ the factory CNG/gas set up?

Wonder where the tank is?
 

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Discussion Starter · #10 ·
I haven't seen a GM, but have seen some Dodges and Fords. Usually, they have a crossbed tank at the front that mounts to the floor. They have a nice enclosure around them, looks like a toolbox. I'm probably going to use a crossbed tank right behind my lp tank, somewhere around 6 gal equivalent capacity. I'm not crazy about losing all my bed space, but don't want to try to mount it over top of the other tank.

The guy that has the refuel station is quite a character. A few years ago he took an older cabover semi tractor and put an old V12 702 CID GMC gas engine in it. He rebuilt the engine with 11:1 pistons and converted it to cng. It has tanks hanging all over it, and really sounds cool.
 

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Discussion Starter · #11 ·
I am going to mount a 16 x 60 cng tank directly behind my lp tank. That size tank will hold 10 gal equivalent of gasoline, or around 1250 cubic feet of gas. Since I do somewhere around 22 mpg on lp, I should get around 30 mpg on the cng, so the tank should have a range of around 300 miles. For test purposes, I will tee the line going into the filterlock. Each line will have a checkvalve. One line will be lp, the other cng. The cng line will come from the outlet of the high pressure regulator at approx 200 psi. I can run on either gas. I probably will run on cng until the tank empties, then the lp will start to flow since it is at lower pressure. The check valves will keep one fuel from backing up into the other tank. Hopefully, I'll get the tank tomorrow and work on getting it mounted. Pics will follow.
 

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Discussion Starter · #12 ·
CNG tank is mounted!

I got the tank mounted. I'll get some pics posted in the next few days. If all goes well, it should be running on methane sometime this week.
 

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Discussion Starter · #13 ·
CNG pics are here!

I just finished running the lines from the cng tank to the engine and to the fill valve. The lines have bends in strange places because I had to use pre-bent lines from another application. The guys supplying the parts gave me this stuff, so I can't complain. The unit mounted under the hood is the high pressure regulator; it takes tank pressure which is up to 3600 psi down to 150. This requires water heating like the lp regulator needs, even though there is no change of state from liquid to gas as there is with lp. The lp line feeds into the outlet of the cng regulator and tees to the line going to the lp filterlock. This way, I use the same low pressure regulator for either fuel. Turn on the tank valve of the fuel I want, and shut off the valve of the one I don't. This setup is just for development, there wouldn't be any reason to have both lp and cng on the same truck. Tomorrow I'll fill the tank, check for line leaks, and see how it works. Stay tuned.
 

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Discussion Starter · #14 ·
System is operational

I filled the tank at our local cng refuel station, then took the truck out on the highway. It drives exactly like propane, except that the ball valve is open more. I drove it about 40 miles. It doesn't ping quite as much under heavy throttle with lots of gas like lp, which is what I expected. CNG has a higher octane rating than lp, so no surprise there. So far, I'm pleased with the results.
 

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Marc,

Is there any reason to choose one gas over the other? More to the point what are the relative benefits of each?

You are truly a pioneer on this board, your next project should be figuring out how to make the DMax run on Naptha!

Keep up the great work!
 

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Discussion Starter · #16 ·
Next on the list is hairspray and cheap perfume.

There isn't much difference between lp and cng from a performance standpoint. I believe the cng is a bit more ping resistant, but not enough to make an issue for it. The two major downsides of cng is storage space and the need of a compressor if you self fill. As you can see by the pic of the tank, that only holds an equivalent of 10 gal of gasoline or a bit over 13 gal of lp. That really limits range, unless you want to fill the whole bed with tanks. It would be great for commuting. CNG is cheaper at the pump than gasoline, I paid $1.90 today. I believe other places are cheaper, but don't know for sure. That $1.90 comes to a bit less per btu than the $1.45 lp I just bought, and I had to get 3000 gal to get that price. So, it may be cheaper to run than lp. If you have access to free gas, you would start paying off the compressor immediately. They cost around $5K. I have free gas at my house, but have resisted using it because I travel too far from home to use it alot of the time. For racing, you would want to stick to a small cng tank because of weight, they are much heavier than lp tanks because they are so thick. Another advantage is there is no road tax on cng, so if you have a big propane tank attached to the truck, you have to pay road tax most of the time.

I will run this for a while and collect some data regarding fuel economy, cost/mile, etc. It really drives exactly the same as with lp, so there isn't much to say about that.
 

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Hey Marc

Please don't start wearing hair spray and cheap perfume....

That crap gives me a headache! ):h :joke:
 

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Discussion Starter · #18 ·
Why would I wear it when I can burn it?):h
 

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Discussion Starter · #19 ·
Update: first trip

I drove 220 miles today. I filled the cng tank, then filled it again when I got back. It took slightly over 10 gal. Seems pretty comparable to the lp consumption I am used to. I'll need to do some more miles to get more accurate numbers. I don't know how much #2 it took, it was on 1/8 tank when I left and is on empty now. I will run it to Indy next week and back, we'll see how it does then.
 

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well come on and get some good #s.

The well drillers are getting closer to our properties.
 
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