Why convert a Jeep to Propane?!?
I will try to keep this from turning into a soapbox/rant. Consider this an open letter to anyone who cares to read it. If you already know you want to convert to propane, you can skip to a FAQ-thing at the bottom.
Each section is a grouping of thoughts, etc.
The quote that sums this all up: "if it wasn't important enough to do something about it, it wasn't important at all" - Anon.
"We have too many high sounding words, and too few actions that correspond with them" Abigail Adams (1744-1818), in a letter to John Quincy Adams, 1774. (from quotationspage.com)
Something I should point out here: True out-of-the-box thinking can only occur when you know where the box is. The end result we're looking for is to get ourselves from point A to point B. The obvious solution is a car (true, until transporters are perfected). Cars have tires (something that is true, but does it need to be? Currently, yes - air cushions do not provide for safe stopping distances). Now we need some way of turning those tires. Currently, we use an internal combustion engine (ICE), route it's power through a transmission, into a differential into those tires. Keep in mind that while we accept this as the most efficient means, it will not always be the case.
Remember also that every time we convert energy from one form to another, we lose a percentage, usually to heat or friction. Sometimes a great percentage, sometimes small. For example, burning propane would make no sense if it's production required more energy and produced more emissions than that of gasoline. Same with hydrogen, when used in an ICE. Electricity is a much more flexible means of stored energy - less heat production, easily converted from one form to another. Unfortunately, converting it to motion is more difficult because we're used to using ICE's, that's where the R&D money has gone for 100 years.
What's my point? A hydrogen-powered fuel cell vehicle is a STEP in the right direction. Until we're using solar-charged electric vehicles, we're making baby steps. Note that current technology for capturing solar energy requires enormous amounts of panels and sunlight to get enough energy for even the most miserly e-car. We won't see this as a practical solution for many many years to come.
Here are my thoughts as I searched for an acceptable solution to my propulsion question.
Functional specifications, Courses of Action and Technical specifications
Discussion: In project management these three terms help us shape ideas into action. The process of determining the two spec sheets has everything to do with the decision making process, weighted and driven by the functional specifications.
We first must identify what we want (our idea). These are the functional specifications. For me, the list includes:
Next we identify the actual process we need to fit these functional specifications. These become the technical specifications. In the course of determining the technical specs, we have gone through a course of action development, and decided which course of action best fits our functional specs. The following courses of action were considered, with a very brief note to it's rejection. Note that these may not seem relevant or complete to someone else (you), because they (you) will have different functional specifications. I can further discuss my evaluation of each COA, if you'd like to email me.
COAs evaluated against the functional specifications, scored 1 to 5 (higher is better):
Then we decide how to implement the action.
Since LPG had the highest score, I went with that system.
The technical specifications for a propane system is quite simple. Liquid service tank, a filter/lockout valve (for safety, vacuum or electric), 350psi + capable hose, a converter (expands the liquid to a gas), and a mixer carburator. See? Easy. Go to the build up page to see how I put it together.
Technical superiority as an internal combustion engine fuel: propane has a few other peculiarities that I like:
Understanding the national and global economy and market as I do (which is classified as "barely"), I can hardly fault the automakers. Here is why I say this: have we, the consumers, decided that fuel economy is our number one requirement? Are we more willing to sacrifice other features (and more money) for a less polluting vehicle? No. Ask someone on the street about an alternative fuel vehicle. They start whining about range, convenience, cost of repairs, blah blah blah. Until the customers decide it's important and "put their money where their mouth is" Detroit (and Tokyo) won't either. Major advances like fuel cells and better batteries cost serious cash, something no company has much of these days. If we won't pay for the next technological advance, why should they? So I guess it's up to the Government to pay for it to get the ball rolling with subsidies ... so I guess we will pay for it after all, won't we?
So the bottom line here is: don't blame the automakers. Think back to the last time you bought a car, what were you looking for and why? If you didn't tell your dealer that fuel economy was your number one constraint, you now understand why no one else is too worried about it either.
I get a lot of emails about how to do a conversion, what do you need, what do the parts do, so here's an email I sent to a fellow Jeeper who asked some questions. I'll tighten this up later but figured I'd paste it here in the meantime in case it can help anyone else:
Parts you need:
Remote fill assembly if you use an
under-body tank. If you use a
forklift tank, skip this one. Hereís
the best picture Iíve got of the remote fill: http://www.jeephead.com/images/myjeep/new%20propane%20filler%20location.jpg
The yellow cap comes off, then you hook up
to the hose they use to fill BBQ tanks. The
end of that filler hose they use is actually an adapter.
You can get fuel at any U-haul, or RV park, or anywhere that fills BBQ
tanks. They will probably freak out
though. Theyíre supposed to charge
you road tax, most donít know how to do it and just skip it, but they could
get fined over a grand for filling and not charging the tax.
I donít ask if they charged me or not.
Thatís my story and Iím sticking to it. LOL
Tank Ė either mounted underneath like mine
This is a Manchester tank, itís 13x13x32, which means itís 32Ē across (and
JUST fits between the frame rails) and two 13Ē diameter tanks welded together.
Takes up a little more room than the gas tank did, I donít think this
will fit in a CJ-5 or CJ-7, and maybe/maybe not in a TJ, itíd take a lot of
measurements, especially with that trackbar on the back axle.
A note on the tank Ė DOT requires a clear path to the ground, because
propane is denser than air. So if
you do the forklift tank, you have to partition it from the passenger
compartment and drill vent holes in the low point of your fuel compartment.
The cost varies widely, I found mine for $250, but a new one can run
$1200. My advice, donít buy
anything until you find a tank, then get the rest of the parts.
Filter/Lockout (aka lockoff) Ė most
important part of the system, it shuts off the flow of fuel in the event of a
major leak or vehicle accident. Two
kinds, electric or vacuum. I like
the electric, itís easier to wire and troubleshoot.
It must be wired through an oil pressure switch (also used with electric
fuel pumps, most auto parts stores carry the Holley brand).
If thereís no oil pressure, like you just got hit by a semi, it shuts
off the electricity, closing the valve, keeping the propane in the tank not
leaking all over the engine fire or whatever.
Obviously, mount this as close to the tank as possible.
In the picture above, you see Iíve got just enough line on it to be
able to lower it. Itís the thing
with lines running in and out of it. Itís
down in the picture, but mounts up in between the two tanks, about the safest
spot on the whole Jeep.
DOT fill hose Ė this is DOT LPG rate hose,
used if you use a remote filler, itís in the vicinity of 7/8Ē OD, and runs
about $3.00/ft. Iíve got about
5í of this, but only really need 3í if I move my filler to the right side
(long story, not worth confusing the issue right now!)
DOT liquid hose Ė this carries your liquid
LPG to the front of your vehicle. Itís
DOT LPG rated for 350psi, youíll probably be at/near 300 psi.
Itís stainless steel braided rubber/nylon coated, and like all the
other lines, take the high-pressure compression fittings which run about $3
each. This line is about ĹĒ OD,
ish, and was $2/ft if I remember right.
DOT vapor hose Ė vent line for your tank,
only about 5í of this and itís about $1.50/ft, two fittings needed (one
being a ďspitĒ valve) at about $2 each.
The spit valve is set at the 80% fill mark on your tank, so when youíre
filling and you crack that fitting and it spits liquid propane out, you know the
tank is at 80% and you can stop filling. This
leaves room for fuel expansion. Another
note on that, your tank is also equipped with a fill shut off which closes the
fill valve at 80%, so thereís really no way to overfill the tank.
The Overfill Protection Valves on the BBQ tanks were borrowed from the
DOT tanks like these.
Converter Ė new $350-ish, I got this and
the mixer off ebay for $35. This
converts liquid propane to vapor. Should
be mounted as close to the mixer as possible.
Should come with two ďYĒ pipes to splice into your heater hose.
If not, itíll freeze up and you go nowhere. Propane
boils at -40deg F, so when you convert from liquid to gas itíll freeze the
moisture out of the air unless you keep it warm with your engine coolant.
Mixer Ė new $350-ish Ė mixes
the propane vapor with incoming air. Two
major brands, Impco and OHG. OHG is
supposed to be better but much harder to find.
Make sure this and your converter are matched to each other and rated for
your horsepower. A forklift setup
wonít keep up with a big L-6 or a V-8. It
mounts on a Holley 4bbl baseplate. The
rest of the engine is pretty much the same.
You can tweak it to optimize the propane but we donít have that kind of
time right now! LOL
I like www.propaneguy.com out of
British Columbia. I got my tanks
from him, great guy, VERY smart on this stuff.
Canadians and Australians are WAY ahead of us on alternative fuels.
Heís got kits and stuff, check him out.
Another resource is Franz Hoffman. Incredibly
smart on Alternative Fuels but also VERY busy.
He always has parts for sale, I got my Dualcurve brainbox from him http://franzh.home.texas.net/
That Dualcurve, or I call it a
brainbox, is a computer that reads an O2 sensor and adjusts your fuel mixture
Ė as close as you can get to EFI without injectors.
The new guys on the block but getting some press with Extreme 4x4 TV and
JP magazine are www.gotpropane.com
theyíve got lots of kits and seem to know what theyíre talking about.
I havenít dealt with them yet but when I get back into the propane side
of my Jeep I certainly will check them out.
Right now Iím in the middle of a major
rebuild on my Jeep, so Iím working on stuff like rollcages, skidplates, front
driveshafts, etc. I got it running and now Iím working on getting it offroad.
Once I get it 4x4 again, Iíll start working on tuning it.
Itís sadly out of tune right now, and Iím not sure that my mixer is
working just right. I got it from a
guy who was running two of them through a blower into a drag racer, so he might
have messed with the guts. Anyway,
it runs so I quit messing with it for the moment.
Iíve only run one full tank through it, and my speedometer was out of
whack for part of the tank. I
believe I got about 12MPG, all stop/go city type driving topping out at 50MPH.
Like I said, it needs LOTS of tuning.
When I tear to it, Iíll get the brainbox
running, then I should see a serious increase in fuel economy, although I
honestly donít care. Iíve got a
high-flow catalytic converter, which takes out the NOx gasses, and propane
doesnít producing any other smog gasses, so I should be at or very very close
to zero emissions. When I get it
tuned up Iím going to take it to Raleigh and run it on the Dyno, see how much
power Iím making and also have a smog check.
For no other reason than bragging rights, but thatís enough of a
Well, I hope that helps, let me know what
other questions you have, and Iíll do my best to help you along.
I had a lot of problems getting information on propane conversions Ė
either guys had quit doing it or had progressed so far they didnít want to
talk to me. If it werenít for Roy
and Franz, Iíd have never figured this stuff out.
Now it's time for your $0.02, pick an email and send me some digits:
Everything below this point is more info and misc junk that I haven't sorted out yet:
A great place to start looking: http://franzh.home.texas.net/
Stoichiometric mix Link
fuel cells and hybrids
auto manu webs; subaru; jeep; toyota; honda; sparrow
Things to search for:
IMPCO Technologies, OHG, Century
manchester tank co
Tel: (253) 846-5994
Fax: (253) 846-6028
Contact: Andy Poulin
|Hatch & Kirk||5111 Leary Ave N/W Seattle, WA 98107||206-783-2766||206-782-6482|
|Teeco Products, Inc.||1601 Pike Street N.W., Auburn, WA 98001||253-735-0222||253-735-1008|
|Northwest Alternative Fuels||11305 207th Street East, Graham, WA 98338-6028||253-846-5994||253-846-6028|