Anybody running propane in their 4.0?

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Recently I've decided I'm tired of having a computer in my XJ. Entirely. Nope. No more sensors, no more check engine light, no more cat. I've recently gotten an address outside the emissions testing boundry. I want to rip the ECU out and add some extra ventilation holes with my .357.

But how do I make it run? 2 options, carb, or propane. With propane I can basically have fuel injection, without the complicated electronics. I can even eliminate the fuel pump. As far as I'm concerned, the less parts, the better.

In the past I've always thought propane was a bad idea since it cost about the same as gas but is only 93k BTU/gal vs 114k for gasoline. But, recently, the state of Oregon, in their infinate wisdom, have outlawed gasoline entirely, 10% ethanol minimum, so the mileage sucks anyway. (I get about 14 now) I could also have a 250 gallon propane tank installed at my shop and have somebody come fill it at a discounted rate, and never have to go to the gas station again. (pumping your own fuel is also illegal in Oregon)

Anyway, what I'm mostly wondering is if anybody else is actually running an XJ on propane? What kind of mileage do you get? I understand the engine can be modified to be more efficient, and more powerful with propane due to it's 100+ octane rating. Super/turbocharger might be a worthwile upgrade...

(just thinking outloud here...)
 
Have not seen propane rig in some time. They were sweet on hills when a carb would tip to the point it's metering systems would flood or starve out the engine. EFI fixed this problem making propane conversion obsolete.
Keep asking a few old times may still be around. You may also need a stand alone ignition.
 
I forgot where i seen it, But i read about a propane 4.0. The guy had 3 tanks 2 was propane and one was gas. He said that he lost 10% mpg but his oil was alot cleaner:compwork:
 
Cool, I never knew you could do this, run a engine on propane I mean. Sorry to kind of jack the post here, but I have no experience in this, but it would seem to me that if you ran it on propane, is there some kind of backfeed prevention system for in case the system were to ignite in a feed tube or something? If this works out, please let me know. I am planning to start a project Jeep next year, and after hearing this might do it to that Jeep just for the hell of it. That would be an awesome upgrade lol. Anyways, I am also very interested to know how well this works. Hate to ask this, but anyone know some more specific links on how to make this work? Thanks,

Paint
 
There are pre-made kits out there to convert most vehicles to propane. It is much more common in Europe where gas is 10 times more ridiculous than it is here. The conversion kits cost a LOT though.

For me though I'll probably try to peice together my own conversion. There's a guy selling almost everything I need on craigslist for $200! Basically it's just a carbureted engine, instead of gas vapor, you use propane vapor. A lot of stuff can be found used from old fleet trucks and fork lifts!

I wonder if a properly modified 4.0 (or stroker) could get as much mileage on propane as I do now on "gasohol"? Can't really do much worse than 14....
 
You might want to talk to gotpropane. They are a great company and know their stuff!! As for running propane I have ran it on my old 1 ton wrangler with an amc 304. It ran really great and I did love the propane because of the no wires simplicity but the having to fill the tank sucked majorly as well as the fact you never knew when you were gonna run out! It takes quite a bit of tuning and I recommend running brand new parts. I bought a used kit and it was junk. Ended up buying everything brand new piece by piece and it ran great then---------------Kyle
 
DoctorPhate said:
Probably wouldn't make much sense for you guys though since Gas is dirt cheap there.
Click to expand...

Local Chevron:
87 octane/10% ethanol = $2.73/gal
100 octane propane = $2.49/gal

Although I completely agree with what you said IF I could actually buy pure gasoline. *sigh* We used to be able to get it in the summer at least, but no more thanks to Governor McGenius.....

I'd really like to have a big tank installed at my shop so I can fill it myself, and I know I can get it delivered for less than the gas station charges. It would be nice to have for heating purposes too...
 
Last edited:
Glacialbass said:
How do you intend to handle the timing without an ECU? I'm guessing that you have a manual if you're planning this as the TCU needs the ECU to function.
Click to expand...

Do 4.2s come with an ECU or TCU? Has nobody ever put an AW4 behind a 4.2L? There's ways to make it work, trust me. ;)
 
so not to sure where to start. one thing to consider is dual fuel in my opinion this is a MUST have unless you live in an area that is constantly warm. the lp needs to vaporize before it gets to the carb, to vaporize lp you need to heat it up. the boiling point of lp is like -44 deg. however under pressure it will stay a liquid. so in the cold oregon am start you xj using gas until the motor warms up, the switch to lp, when you switch to lp it MUST run through a vaporizer. there is alot you will need misc fuel lines, vaporizer, regulator, and a DOT tank. you can use a bbq bottle but it would be illegal. it all is extremely possible.

check out REGO regulators for parts american made and great priced

where would you get the gas? you could rent a tank, but you will also need a pump to transfer fuel and most companys wont like that due to liability. best bet would be to find a mom and pop lp shop that fills bottles by the gallon not the weight.

i work in the propane industry so let me know if you have any specific questions.
 
I have been looking into this whole propane thing a bit in my free time over the last few weeks, since you offer possible answers, I was curious, I am looking at possibly restoring an older 1966 Commando. Not necessarily as a road vehicle, just to play around with around the house and my grandpas farm. In such a situation, how long would say a 10 gallon grilling propane tank last me if I were to do the modification? Also, think it would even be worth it? i know it sounds like a odd question, but I was thinking sort of doing this as a test vehicle, then if all goes good maybe doing it to my Xj or like a duel fuel mod for it later down the road. One more quick question What are the more major differences between doing this kind of conversion to a Fuel Injected engine vs. a carbourated (please forgive the spelling there lol) engine? Thanks for your help.

Paint
 
Local Chevron:
87 octane/10% ethanol = $2.73/gal
100 octane propane = $2.49/gal

Interesting numbers....

propane-$2.49 a gallon at 93000 BTU per gal =.0000267 cents per BTU
87 octane/10% eth.- $2.73 a gallon at 111688 BTU per gallon =.0000244 cents per BTU

(per EPA website, pure gas has 115500 BTU per gallon, and 10% ethanol has 3.3% less than that, so thats where I got the 111688)

Seems like E10 is more economical from an energy standpoint.
 
it would be cool to do dont get me wrong, if you are just looking to putt around the farm and would have no issue with the cost of the initial investment, i would say go for it. the loss of power, and efficency by using LPG is ABOUT 25%. i cannot say how long it will last in a 10 gallon tank but. if you average 400 miles per tank on gasoline with lpg it would get approximately 300 miles per tank. due to BTU there will be loss. however throughout time it will pay off. last year gas in colorado hit 4.25 or so a gallon the highest i have ever sold propane for is 2.40. also lpg is a million times cleaner and better for your engine! less oil changes and engine wear.

dual fuel is typically a must. the LPG must be a vapor before it reaches the carb. if it is still a liquid when it hits the compression stroke kiss you motor good by!

efi is extremely difficult to run on propane it is extremely complex and expensive. i know roush makes kits for newer fords, but i havent seen a kit for our 4.0's yet. if it was affordable and available i would totally do it in a heart beat.

you guys all need to remember these tanks reguardless of any size or shape should be D.O.T. approved, and be protected and properly ventilated.

TOMMYR- who did you contact for that price on LPG? is it bulk, residential, commercial price? gas in CO is about 2.49 i sell LPG for 1.89
 
you should also look into compressed natural gas. it's even cheaper!
i'm converting a chevy 350 to run on it currently check this out...
http://cngoutfitters.com
the guy is real nice, and you don't necesarily hafta use his kit, since it's expensive, but you might be abl to get around it... and you can compress it from a line at home!
 
That natural gas link is really cool, but too expensive for me lol. Awesome idea though! Especially the whole 4.x gallons for $3 part in the video lol.

I will hold off the conversion on my Xj for quite some time lol, too expensive of a mod right now.

As far as the tank approval goes, personally if I did the mod to the commando I am thinking of rebuilding, that rig would be off road only, I would still build a blast tube for the tank to sit in though lol. Perhaps later down the road Might upgrade to a better tank for road use, depends on what I end up doing to it lol.

So how difficult is this thing really to do? The conversion I mean. Thanks.

Paint
 
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