i've got an off-road toy that i am wanting to convert from gasoline. i originally wanted to go propane, but a buddy of mine mentioned natural gas. i was wondering, which would be better? i know you don't quite net the same hp #'s from these fuels but am also aware of it being "poor man's fuel injection". what kind of efficiency would i be lookin at (not a real big concern), which is usually cheaper, and which has more power? how hard would this swap be, and what kind of $$$ figures am i lookin at? any and all info is appreciated.

 

Go with wood gas and laugh when you take your hatchet clear a trail and at the same
time refuel your rig!! The Gengas Page
If you were going to use it on extreme angles maybe mounting the pyrolizer in a gimble
to keep it relatively upright in relation to the ground would help. That wood pellet
stove fuel is a good fuel and you can probably get it in your area and would be and ideal
fuel to use.
Of course I amgoing to get flamed by everyone for even mentioning a alternative to
mined hydrocarbons.
If you look closely at a camp fire you will see the wood is not actually burning but the
fuel is being liberated by the heat. If you smothered the flame without killing the heat
it wood make the "gas" and you could reignite it from a considerable distance. Ever put
a lid on a charcoal fire and then remove it and have a fireball? I am just giving you an
alternative take it or leave it I really don't care if you use it, hate it or have stock in
the gas industry.

 

wow...thats the one thing i have never heard of. always heard jokes about using wood in a "fossil fuel engine". how much space would it take up? no i dont have stock in any oil companies, and i love hearing about alt fuels.

 

Propane or natural gas? The problems are many IMHO. First natural gas filling stations are few. Second fuel mileage & HP suffer. If you take the cost to covert plus the savings on say propane if you put it on paper I believe you will see there is no savings to be had. Being around the conversions in the 80s I can tell you that if you try to convert so you can use either propane or gasoline your in for headaches. The only conversions that work well are changing over to ALL PROPANE or NATURAL GAS.

 

i really appreciate the info kermmy, and beleive me i have really considered these things....however, first off i have a natural gas well in my back yard (really the ONLY reason i want natural gas). second, this truck will rarely see road time (one of two reasons i am not worried much about efficiency). which brings me to the whole reason i want either (or both) of these options...it is to my very limited experience that propane and natrual gas can be ran through a carb'ed engine up and down hills and other steep, off-camber driving situations with close to the same reliability as a fuelie system without the cost or complications of converting. but i did want to completely eliminate gasoline being used in this particular truck (think of it more as a really, really big quad). but thanks for the info just the same, at least now i know what to stay away from and what else to consider. i hope this clears up any misunderstandings

 

In a properly set up bi fuel system you will notice very little or no power loss and very little difference in MPG, But I believe your not real concerned about MPG you want power and the ability to operate at extreme angles so either will work well your biggest issue on Nat Gas is going to be fuel storage a refuel expense/time. Basicly your fuel is "free" however to get it compressed into a tank to give you some operating time is going to be rather salty. With LP (if your supplier is willing) you could set up a storage tank on your property so you could re-fuel in 10 mins or so for a couple of grand or less.
And if you get a large enough tank you could haul around 80 gals in your bed.
Like I said if its set up right you will be very happy.

Regards

 

FYI, natural-gas systems have tanks that have nowhere near the range of propane (because natural-gas is not readily liquified, it needs to be -256 degrees F to liquify, taking unbelievable energy and money). Also natural-gas tanks are pressurized to somewhere in the neighborhood of 3000psi (I think propane is 250 max and thats at relief). Even if you could take sweet gas (I pray its not sour) from your backyard well it can be very unstable. Is it processed or raw? Has a gas analysis been done on the well? What is its composition? Not to mention the gas well can easily change over time. Natural gas has many other components in it..... even after process (sulfer, mercury, carbon dioxide, and water just to name a couple, and all can be in varying amounts). Not to try and scare anybody but, the gas could easily destroy your engine or even harm you. So after all that, if you want greater range, safety, and inexpensive, go propane. Remember, I think propane has an octane rating of around 104 so some compression is in order. That was the earlier propane conversions down fall. People converted there 80s low compression engines to propane/dual fuel and had no power on propane giving it a bad name. An engine needs to be optimized for the fuel it is using.....even if its wood......Imagine the torque of a steam engine on the trails, who needs gears.

 

thanks, thats the kind of stuff i am wanting to hear. and i really think the cng is officially out of the question. my truck will have a 1968 460 in it, but i am planning on a rebuild and some mods while its apart. so what kind of compression can i reliably run? how about if i go with forced induction? any recommendations?

 

I dont have much for experience with propane, but ill give you what little I got. I think somewhere around 11 or 12:1 compression is a good starting place for natural aspirated (some run higher but ive heard these are reasonable and reliable numbers). Many things come into play when deciding on a compression ratio just like gasoline. Heads, cam/timing, alltitude, forced induction, fuel (even propane composition can vary from region to region,mainly butane content I think, but it effects the octane rating). One of the main things to remember is that propane does not have anywhere close to the cooling effect that gasoline has on the cylinder and valves. So premium valves and hardend seats in the heads are a must. valve seals may need to be different because of the extra heat and dry fuel gas. Ive also been told to shy away from aluminum heads because they can be too easily warped. Some run aluminum, but I personaly know of a few guys that are pulling the aluminum heads on their newer propane converted trucks after very few miles (dont know if they were tuned properly though?) Forced induction?? I know its going to add that much more heat. Obviously the CR will have to be adjusted accordingly to how much boost you will plan on running? Again, this is what little I know, hopefully I helped a bit.

 

yea, it helps. i am wanting to keep my truck as reliable as possible, i planned on running the stock intake manifold for now and definitley the stock heads. not a big fan of aluminum. maybe a port and polish on the heads. the bottom end is where the mods will lie. im wanting to bore/stroke my 460 to a 521 and get a good low-end cam. i have a line on an 8-71 blower, but im not sure how much boost they even put out...i know it has to do with the size of the blower and your belt gear but thats about it, now im in the dark with forced induction. i've also heard that turbos are more of a top-end type of forced induction, which makes sense to me because of how they work.

the heat thing has me a bit worried tho. i am wanting to reroute my radiator to my bed, and since i have no actual experience with such a feat, im not sure if this will help or hurt my cooling. i'd imagine it'd be better since it wouldnt be in such a small space where heat couldnt escape very well, not to mention gettin heat from the engine itsself. i know that engine driven fans can suck up to 20 hp from and engine, and my electric fan should cool better anyway (i cant exactly remember, but i know it pulls at least 2000 cfm).

also, i know they say that smaller primaries (on headers) are better for more torque, but if propane generates more heat than gasoline, would larger primaries help cool the engine better because they can get rid of the exhaust quicker? or am i just overthinking?

well, i think thats everything for now. thanks again guys, keep the thoughts coming

 

There is a man in Huntsburg Oh that has done some Racing with Propane. You might give him a call. I beleive his name is Tad Thurling

J P PROPANE GAS SERVICE INC 440 6365121
12405 MADISON ROAD
P.O BOX 309
HUNTSBURG OH 44046

Good Luck

 

An 8-71 is about correct for your displacment goals. (These are Approx numbers) 454-550 cubes, with a 1:1 drive ratio will put out 8-12 pounds of boost on a 6000rpm street engine. Obviously cam, heads exhaust are going to effect these numbers a bit as well, but the blower can be overdriven (like 35 percent to 24 pounds) or underdriven (15 percent down to 2 pounds) to suit your needs. Now as for turbos, they are awsome at producing low end torque! Again this is a matter of proper tuning and correct size turbo. Also a turbo in a sense uses "free" energy to create power, while a supercharger draws quite a bit of parasitic power from the engine to create power. On the down side, turbos are a bit more involved and generally cost alot more to set up.

 

Moving the rad to the box isnt a problem, as long as you can get air across that rad. Moving it out of the engine bay will help keep under hood temps down. Offroad racers use a combo of electric fans and scoops/deflectors, but your truck is a trail rig and scoops will not help much. So an oversized rad and dual fans (4000 cfm) is just about a must (especially if you boost it). A larger alternator will be a needed upgrade to run electric fans (even a DERALE 2200cfm single draws just about 25 amps). In my opinion, its good to over build your cooling system.

 

okay, i know this is off-topic but how about two stock radiators with fans? im actually considering running no tailgate and then havin my radiators either in the back of the bed or back by the wheel wells. i doubt the waterpump will move coolant all the way back there, tho...still trying to figure out that hurdle. any recommendations on an alternator, cuz i actually need one anyway.

 

Id stick with one large rad and a dual electric fan, but thats just me. Two rads could be done but I dont like extra complexity or the idea of more weight, more places to leak/air lock, and taking up more space than necessary. A high volume water pump would probably be sufficiant. As for an alternator, from what I hear powermaster and mean green are a couple of well known names. It all depends on how much money you want to spend. Max amperage from an aftermarket single automotive alternator is usually around 200-250 amps (which is significant but 400-500 dollars). You can go really hard core with companys like zena and premier power, want to weld?! (try 900-1200 dollars! for premier).