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propane questions

0

043500

NAXJA Forum User
Location
Ocala, FL USA
Am considering running my 2.5LTBI comanche with a propane system instead of gasoline. I know the good, bad, and ugly of doing this so please don't chastize me...I'm not even 100% on it yet.


My question(s) is...with the TBI motor...how much of the wiring harness/computer is needed? Meaning will I need to computer etc to run the spark/timing etc?? Also...how much wiring/computer stuff is on the 2.5L 1 bbl carb motor ...if it would be simpler I'd just swap in the carb motor and put the propane on that...???
 
You're going to need the computer and wiring harness for spark timing etc, with the tbi, except yuo'll have to disable the electric fuel pump.

Converting the tbi motor to propane isn't much more complicated than converting a carburated motor, with the exception that you may need a so called "superfix" box which ties in with you're exsisting wiring harness and prevents the computer from setting a lean exhaust code.
 
I have run propane on vehicles for years on the farm. We ran dual fuel. A switch was used to run solenoids to turn off the gas and the propane on. Back when we ran leaded fuel, propane burned a lot cleaner and the engine lasted a lot longer. That isn't as big a deal now with no lead fuel. I think the figures are that you lose about 5% power running propane. In cold weather, due to low vapor pressure, we started on gas, then switched to propane. I can't see a real reason to run propane other than it burns a lot cleaner. Forklifts commonly run on propane due to being used in confined spaces.

On the farm, we got the propane without paying road taxes and federal taxes on it. While it was legal for use on farm machinery, using it on the highway without paying the taxes was illegal.
 
jpnjason said:
http://www.gotpropane.com

a very cool site, and a cool guy doing the work.
Click to expand...

That's where I've done some fishing around so far. He's got a kit for the 2.5L (injected or carb).

Why propane?? Well...around here it's not any more $$ the regular unleaded...and in some places it's less. PLUS the economy is nearly the same as well...meaning the same MPG. The thought of eliminating the fuel pump (in fact the entire stock fuel system) is appealing. Plus I can mount the tank anywhere in any position...no worries on spills, loss of power is negligeable and power gains can be had if set up right. It's just a simpler setup and despite the money seems worth it in my opinion for the purposes of my offroading. I'm in the early stages of a ground up build on an almost 20 year old vehicle...on which I know I would have to replace most of...if not the entire fuel system anyway. SO why not make a change??
 
I run it on my buggy the only thing that sucks about propane is your buddy next to you on the trail most likely doesn't have any if you run out i have been saved by a BBQ tank before but other than that it's great good luck on what you decide
 
043500 said:
PLUS the economy is nearly the same as well...meaning the same MPG.
Click to expand...

You need to go do some more research. That is most definately NOT true. If that was the case everybody would be using propane.
 
ZmOz said:
You need to go do some more research. That is most definately NOT true. If that was the case everybody would be using propane.
Click to expand...

I use propane to run my 200kW Kohler generators and they're much more efficient.

SPOBI
 
ECKSJAY said:
I use propane to run my 200kW Kohler generators and they're much more efficient.

SPOBI
Click to expand...

And how much does a generator have to do with an old 4 cylinder jeep engine? I imagine your generator was a diesel to start with, and thus high compression where propane can be more efficient. But if you just slap a propane carb onto an automotive engine you will get significantly worse mileage unless you build the engine for the propane.
 
Propane would be good on a trail rig that currently has a carb set-up because it is immune to high angle problems...in fact it would keep running upside down until it used all the liquid in the line from the tank. Another advantage (if you have a motor that can utilize high octane fuel) is the effective octane of 110...the down sides are where do you mount a tank big enough and the lower milage based on pounds per hour compared to gasoline.
 
ZmOz said:
But if you just slap a propane carb onto an automotive engine you will get significantly worse mileage unless you build the engine for the propane.
Click to expand...

Ok. With all the searching etc I have done...the WORST I have seen mileage wise for a stock motor on propane was about a 10-15% loss in fuel economy. THe 'gotpropane' guy sells 8 and 10 gallon (~43 lb) forklift tanks. THis is said to be nearly the equivalent of 10 gallons or gasoline. How is this 'significantly' worse?
If I'm getting 15 MPG to start...a 1.5 MPG loss on a 95% trail rig is not 'significant' enough for me. AND yes I realize I won't get 15 MPG while running offroad.
 
043500 said:
Ok. With all the searching etc I have done...the WORST I have seen mileage wise for a stock motor on propane was about a 10-15% loss in fuel economy.
Click to expand...

How much is it going to cost you to convert to propane? Probably somewhere around $500. You've already got a perfectly good gas tank...why the hell would you want to spend alot of money converting to a fuel that gives you less mileage, less power, less range, takes longer to fill, and has no fuel gauge? There are no benefits to propane when you're starting with a motor that is already fuel injected. Even if you got the same mileage and power with propane (which you won't) there's still no benefit to propane.
 
hi-jack.

I saw a company that lets you run used vegtable oil in a diesel motor! Most dinner actually will PAY you to take there fryer oil!


Sorry, just had to throw it out.
 
re hijack
yup it's called bio-diesel you can buy it or make it yourself. it's a little more expensive when bought and can be almost free if you make it yourself.
 
ZmOz said:
How much is it going to cost you to convert to propane? Probably somewhere around $500. You've already got a perfectly good gas tank...why the hell would you want to spend alot of money converting to a fuel that gives you less mileage, less power, less range, takes longer to fill, and has no fuel gauge? There are no benefits to propane when you're starting with a motor that is already fuel injected. Even if you got the same mileage and power with propane (which you won't) there's still no benefit to propane.
Click to expand...

That's just it...as I stated above...I don't have a good gas tank...and I'm 90% certain I will need to repair/replace the rest of the fuel system as well. And to do it RIGHT ...it would cost about the same as converting to propane.

I guess my request to not have anyone chastize me(maybe too strong a word) went unoticed.

I was asking a question concerning the existing wiring/computer setup with propane intead of gasoline. But I guess some folks can't resist.

Another question: For those of you who are 'anti-propane'...how many of you are running it NOW or have in the recent past? I'm not talking "Well I had a forklift 20 years ago and it got terrible mileage..blah blah". I mean on a jeep (or other rig) that was mostly offroad, and running a mostly stock motor.

I ask again...if you have nothing constructive please leave it alone unless you can provide with something other than "my mother's borther's roomate's 2nd cousin runs propane and it sucks".

For those who have responded (good or bad) with real info I appreciate it.
 
Just trying to help, it makes absolutely no sense to run propane. If propane had some advantage, ANYTHING, then it might be a good idea, but it doesn't. Please tell me, why do you want to run an inferior fuel that costs more?
 
ZmOz said:
Just trying to help, it makes absolutely no sense to run propane. If propane had some advantage, ANYTHING, then it might be a good idea, but it doesn't. Please tell me, why do you want to run an inferior fuel that costs more?
Click to expand...

He has already decided he wants to. Why are you so vehement he not do it? Maybe he wants something different, maybe he wants to just because he can. Cut the guy some slack and get off your "you're stupid to convert" campaign. His question wasn't whether he should or not, but rather if he needed to keep the ecu for the ignition. You have made your opinion known.
 
kunaji said:
He has already decided he wants to. Why are you so vehement he not do it? Maybe he wants something different, maybe he wants to just because he can. Cut the guy some slack and get off your "you're stupid to convert" campaign. His question wasn't whether he should or not, but rather if he needed to keep the ecu for the ignition. You have made your opinion known.
Click to expand...

That's his nature.
 
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